1
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Symonds JD, Park KL, Mignot C, Macleod S, Armstrong M, Ashrafian H, Bernard G, Brown K, Brunklaus A, Callaghan M, Classen G, Cohen JS, Cutcutache I, de Sainte Agathe JM, Dyment D, Elliot KS, Isapof A, Joss S, Keren B, Marble M, McTague A, Osmond M, Page M, Planes M, Platzer K, Redon S, Reese J, Saenz M, Smith-Hicks C, Stobo D, Stockhaus C, Vuillaume ML, Wolf NI, Wakeling EL, Yoon G, Knight JC, Zuberi SM. POLR3B is associated with a developmental and epileptic encephalopathy with myoclonic-atonic seizures and ataxia. Epilepsia 2024. [PMID: 39348199 DOI: 10.1111/epi.18115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 08/22/2024] [Accepted: 08/22/2024] [Indexed: 10/02/2024]
Abstract
OBJECTIVE POLR3B encodes the second largest subunit of RNA polymerase III, which is essential for transcription of small non-coding RNAs. Biallelic pathogenic variants in POLR3B are associated with an inherited hypomyelinating leukodystrophy. Recently, de novo heterozygous variants in POLR3B were reported in six individuals with ataxia, spasticity, and demyelinating peripheral neuropathy. Three of these individuals had epileptic seizures. The aim of this article is to precisely define the epilepsy phenotype associated with de novo heterozygous POLR3B variants. METHODS We used online gene-matching tools to identify 13 patients with de novo POLR3B variants. We systematically collected genotype and phenotype data from clinicians using two standardized proformas. RESULTS All 13 patients had novel POLR3B variants. Twelve of 13 variants were classified as pathogenic or likely pathogenic as per American College of Medical Genetics (ACMG) criteria. Patients presented with generalized myoclonic, myoclonic-atonic, atypical absence, or tonic-clonic seizures between the ages of six months and 4 years. Epilepsy was classified as epilepsy with myoclonic-atonic seizures (EMAtS) in seven patients and "probable EMAtS" in two more. Seizures were treatment resistant in all cases. Three patients became seizure-free. All patients had some degree of developmental delay or intellectual disability. In most cases developmental delay was apparent before the onset of seizures. Three of 13 cases were reported to have developmental stagnation or regression in association with seizure onset. Treatments for epilepsy that were reported by clinicians to be effective were: sodium valproate, which was effective in five of nine patients (5/9) who tried it; rufinamide (2/3); and ketogenic diet (2/3). Additional features were ataxia/incoordination (8/13); microcephaly (7/13); peripheral neuropathy (4/13), and spasticity/hypertonia (6/13). SIGNIFICANCE POLR3B is a novel genetic developmental and epileptic encephalopathy (DEE) in which EMAtS is the predominant epilepsy phenotype. Ataxia, neuropathy, and hypertonia may be variously observed in these patients.
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Affiliation(s)
- Joseph D Symonds
- Paediatric Neurosciences Research Group, School of Health and Wellbeing, University of Glasgow, Glasgow, UK
- Royal Hospital for Children, Glasgow, UK
| | - Kristen L Park
- Children's Hospital Colorado, Anschutz Medical Campus, University of Colorado, Aurora, Colorado, USA
| | - Cyril Mignot
- Département de Génétique, Groupe Hospitalier Pitié-Salpêtrière-Hôpital Trousseau, Sorbonne Université, Paris, France
| | | | | | - Houman Ashrafian
- Division of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK
- Department of Experimental Therapeutics, Radcliffe Department of Medicine, John Radcliffe Hospital, Oxford, UK
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Quebec, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research, Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Kathleen Brown
- Department of Pediatrics, Section of Genetics and Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, School of Health and Wellbeing, University of Glasgow, Glasgow, UK
- Royal Hospital for Children, Glasgow, UK
| | - Mary Callaghan
- Department of Paediatrics, University Hospital Wishaw, Wishaw, UK
| | - Georg Classen
- Children's Center Bethel, University Bielefeld, Bielefeld, Germany
| | - Julie S Cohen
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | | | - David Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | | | - Arnaud Isapof
- Service de Neuropédiatrie, Hôpital Trousseau, Sorbonne Université, Paris, France
| | - Shelagh Joss
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Boris Keren
- Department of Genetics, Pitié-Salpêtrière Hospital, APHP. Sorbonne Université, Paris, France
| | - Michael Marble
- Division of Pediatric Genetics, Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Amy McTague
- Developmental Neurosciences. Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Matthew Osmond
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | | | - Marc Planes
- Service de Génétique Médicale et Biologie de la Reproduction, CHU de Brest, Brest, France
- Laboratoire de Biologie Médicale Multi-Sites SeqOIA, Paris, France
- Université Brest, Brest, France
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Sylvia Redon
- Service de Génétique Médicale et Biologie de la Reproduction, CHU de Brest, Brest, France
- Laboratoire de Biologie Médicale Multi-Sites SeqOIA, Paris, France
- Université Brest, Brest, France
| | - James Reese
- Presbyterian Healthcare System, Albuquerque, New Mexico, USA
| | - Margarita Saenz
- Department of Pediatrics, Section of Genetics and Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Constance Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Daniel Stobo
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Christian Stockhaus
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Marie-Laure Vuillaume
- Laboratoire de Biologie Médicale Multi-Sites SeqOIA, Paris, France
- UMR 1253, iBrain, University of Tours, Tours, France
- Genetics Department, University of Tours, Tours, France
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma's Children's Hospital, Amsterdam UMC, Vrije Universiteit, Amsterdam, The Netherlands
| | - Emma L Wakeling
- North East Thames Regional Genetic Service, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Grace Yoon
- Departments of Paediatrics and Molecular Genetics, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Julian C Knight
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, School of Health and Wellbeing, University of Glasgow, Glasgow, UK
- Royal Hospital for Children, Glasgow, UK
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2
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Coulombe B, Chapleau A, Macintosh J, Durcan TM, Poitras C, Moursli YA, Faubert D, Pinard M, Bernard G. Towards a Treatment for Leukodystrophy Using Cell-Based Interception and Precision Medicine. Biomolecules 2024; 14:857. [PMID: 39062571 PMCID: PMC11274857 DOI: 10.3390/biom14070857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/12/2024] [Accepted: 07/14/2024] [Indexed: 07/28/2024] Open
Abstract
Cell-based interception and precision medicine is a novel approach aimed at improving healthcare through the early detection and treatment of diseased cells. Here, we describe our recent progress towards developing cell-based interception and precision medicine to detect, understand, and advance the development of novel therapeutic approaches through a single-cell omics and drug screening platform, as part of a multi-laboratory collaborative effort, for a group of neurodegenerative disorders named leukodystrophies. Our strategy aims at the identification of diseased cells as early as possible to intercept progression of the disease prior to severe clinical impairment and irreversible tissue damage.
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Affiliation(s)
- Benoit Coulombe
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T 1A8, Canada
| | - Alexandra Chapleau
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- The Neuro’s Early Drug Discovery Unit (EDDU), McGill University, Montréal, QC H9X 3V9, Canada;
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Thomas M. Durcan
- The Neuro’s Early Drug Discovery Unit (EDDU), McGill University, Montréal, QC H9X 3V9, Canada;
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Yena A. Moursli
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Denis Faubert
- Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada;
| | - Maxime Pinard
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montréal, QC H4A 3J1, Canada
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3
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LeDoux MS. Polymerase I as a Target for Treating Neurodegenerative Disorders. Biomedicines 2024; 12:1092. [PMID: 38791054 PMCID: PMC11118182 DOI: 10.3390/biomedicines12051092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/06/2024] [Accepted: 05/11/2024] [Indexed: 05/26/2024] Open
Abstract
Polymerase I (Pol I) is at the epicenter of ribosomal RNA (rRNA) synthesis. Pol I is a target for the treatment of cancer. Given the many cellular commonalities between cancer and neurodegeneration (i.e., different faces of the same coin), it seems rational to consider targeting Pol I or, more generally, rRNA synthesis for the treatment of disorders associated with the death of terminally differentiated neurons. Principally, ribosomes synthesize proteins, and, accordingly, Pol I can be considered the starting point for protein synthesis. Given that cellular accumulation of abnormal proteins such as α-synuclein and tau is an essential feature of neurodegenerative disorders such as Parkinson disease and fronto-temporal dementia, reduction of protein production is now considered a viable target for treatment of these and closely related neurodegenerative disorders. Abnormalities in polymerase I activity and rRNA production may also be associated with nuclear and nucleolar stress, DNA damage, and childhood-onset neuronal death, as is the case for the UBTF E210K neuroregression syndrome. Moreover, restraining the activity of Pol I may be a viable strategy to slow aging. Before starting down the road of Pol I inhibition for treating non-cancerous disorders of the nervous system, many questions must be answered. First, how much Pol I inhibition can neurons tolerate, and for how long? Should inhibition of Pol I be continuous or pulsed? Will cells compensate for Pol I inhibition by upregulating the number of active rDNAs? At present, we have no effective and safe disease modulatory treatments for Alzheimer disease, α-synucleinopathies, or tauopathies, and novel therapeutic targets and approaches must be explored.
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Affiliation(s)
- Mark S. LeDoux
- Department of Psychology and College of Health Sciences, University of Memphis, Memphis, TN 38152, USA; or
- Veracity Neuroscience LLC, Memphis, TN 38157, USA
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Rey F, Esposito L, Maghraby E, Mauri A, Berardo C, Bonaventura E, Tonduti D, Carelli S, Cereda C. Role of epigenetics and alterations in RNA metabolism in leukodystrophies. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1854. [PMID: 38831585 DOI: 10.1002/wrna.1854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Leukodystrophies are a class of rare heterogeneous disorders which affect the white matter of the brain, ultimately leading to a disruption in brain development and a damaging effect on cognitive, motor and social-communicative development. These disorders present a great clinical heterogeneity, along with a phenotypic overlap and this could be partially due to contributions from environmental stimuli. It is in this context that there is a great need to investigate what other factors may contribute to both disease insurgence and phenotypical heterogeneity, and novel evidence are raising the attention toward the study of epigenetics and transcription mechanisms that can influence the disease phenotype beyond genetics. Modulation in the epigenetics machinery including histone modifications, DNA methylation and non-coding RNAs dysregulation, could be crucial players in the development of these disorders, and moreover an aberrant RNA maturation process has been linked to leukodystrophies. Here, we provide an overview of these mechanisms hoping to supply a closer step toward the analysis of leukodystrophies not only as genetically determined but also with an added level of complexity where epigenetic dysregulation is of key relevance. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNA RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Federica Rey
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Letizia Esposito
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Erika Maghraby
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
- Department of Biology and Biotechnology "L. Spallanzani" (DBB), University of Pavia, Pavia, Italy
| | - Alessia Mauri
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Clarissa Berardo
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Eleonora Bonaventura
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Davide Tonduti
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Stephana Carelli
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Cristina Cereda
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
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5
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Ulhaq ZS, You MS, Jiang YJ, Tse WKF. p53 inhibitor or antioxidants reduce the severity of ethmoid plate deformities in zebrafish Type 3 Treacher Collins syndrome model. Int J Biol Macromol 2024; 266:131216. [PMID: 38556235 DOI: 10.1016/j.ijbiomac.2024.131216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/19/2024] [Accepted: 03/26/2024] [Indexed: 04/02/2024]
Abstract
Treacher Collins syndrome-3 (TCS-3) is a rare congenital craniofacial disorder attributed to variants in the RNA pol I subunit C (POLR1C). The pathogenesis of TCS-3 linked to polr1c involves the activation of apoptosis-dependent p53 pathways within neural crest cells (NCCs). This occurs due to disruptions in ribosome biogenesis, and the restoration of polr1c expression in early embryogenesis effectively rescues the observed craniofacial phenotype in polr1c-deficient zebrafish. Clinical variability in TCS patients suggests interactions between genes and factors like oxidative stress. Elevated production of reactive oxygen species (ROS) in epithelial cells may worsen phenotypic outcomes in TCS individuals. Our study confirmed excessive ROS production in facial regions, inducing apoptosis and altering p53 pathways. Deregulated cell-cycle and epithelial-to-mesenchymal transition (EMT) genes were also detected in the TCS-3 model. Utilizing p53 inhibitor (Pifithrin-α; PFT-α) or antioxidants (Glutathione; GSH and N-Acetyl-L-cysteine; NAC) effectively corrected migrated NCC distribution in the pharyngeal arch (PA), suppressed oxidative stress, prevented cell death, and modulated EMT inducers. Crucially, inhibiting p53 activation or applying antioxidants within a specific time window, notably within 30 h post-fertilization (hpf), successfully reversed phenotypic effects induced by polr1c MO.
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Affiliation(s)
- Zulvikar Syambani Ulhaq
- Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan; Research Center for Pre-clinical and Clinical Medicine, National Research and Innovation Agency, Cibinong 16911, Indonesia.
| | - May-Su You
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County 350, Taiwan
| | - Yun-Jin Jiang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County 350, Taiwan
| | - William Ka Fai Tse
- Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan.
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6
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Khan H, Harripaul R, Mikhailov A, Herzi S, Bowers S, Ayub M, Shabbir MI, Vincent JB. Biallelic variants identified in 36 Pakistani families and trios with autism spectrum disorder. Sci Rep 2024; 14:9230. [PMID: 38649688 PMCID: PMC11035605 DOI: 10.1038/s41598-024-57942-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 03/22/2024] [Indexed: 04/25/2024] Open
Abstract
With its high rate of consanguineous marriages and diverse ethnic population, little is currently understood about the genetic architecture of autism spectrum disorder (ASD) in Pakistan. Pakistan has a highly ethnically diverse population, yet with a high proportion of endogamous marriages, and is therefore anticipated to be enriched for biallelic disease-relate variants. Here, we attempt to determine the underlying genetic abnormalities causing ASD in thirty-six small simplex or multiplex families from Pakistan. Microarray genotyping followed by homozygosity mapping, copy number variation analysis, and whole exome sequencing were used to identify candidate. Given the high levels of consanguineous marriages among these families, autosomal recessively inherited variants were prioritized, however de novo/dominant and X-linked variants were also identified. The selected variants were validated using Sanger sequencing. Here we report the identification of sixteen rare or novel coding variants in fifteen genes (ARAP1, CDKL5, CSMD2, EFCAB12, EIF3H, GML, NEDD4, PDZD4, POLR3G, SLC35A2, TMEM214, TMEM232, TRANK1, TTC19, and ZNF292) in affected members in eight of the families, including ten homozygous variants in four families (nine missense, one loss of function). Three heterozygous de novo mutations were also identified (in ARAP1, CSMD2, and NEDD4), and variants in known X-linked neurodevelopmental disorder genes CDKL5 and SLC35A2. The current study offers information on the genetic variability associated with ASD in Pakistan, and demonstrates a marked enrichment for biallelic variants over that reported in outbreeding populations. This information will be useful for improving approaches for studying ASD in populations where endogamy is commonly practiced.
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Affiliation(s)
- Hamid Khan
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada
- Department of Biological Sciences, International Islamic University Islamabad, Islamabad, Pakistan
| | - Ricardo Harripaul
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Anna Mikhailov
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada
| | - Sumayah Herzi
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada
| | - Sonya Bowers
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada
| | | | - Muhammad Imran Shabbir
- Department of Biological Sciences, International Islamic University Islamabad, Islamabad, Pakistan
| | - John B Vincent
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Centre for Addiction and Mental Health, 250 College St, Toronto, ON, M5T 1R8, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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7
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Coulombe B, Durcan TM, Bernard G, Moursli A, Poitras C, Faubert D, Pinard M. The 37TrillionCells initiative for improving global healthcare via cell-based interception and precision medicine: focus on neurodegenerative diseases. Mol Brain 2024; 17:18. [PMID: 38605409 PMCID: PMC11007934 DOI: 10.1186/s13041-024-01088-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
One of the main burdens in the treatment of diseases is imputable to the delay between the appearance of molecular dysfunctions in the first affected disease cells and their presence in sufficient number for detection in specific tissues or organs. This delay obviously plays in favor of disease progression to an extent that makes efficient treatments difficult, as they arrive too late. The development of a novel medical strategy, termed cell-based interception and precision medicine, seeks to identify dysfunctional cells early, when tissue damages are not apparent and symptoms not yet present, and develop therapies to treat diseases early. Central to this strategy is the use of single-cell technologies that allow detection of molecular changes in cells at the time of phenotypical bifurcation from health to disease. In this article we describe a general procedure to support such an approach applied to neurodegenerative disorders. This procedure combines four components directed towards highly complementary objectives: 1) a high-performance single-cell proteomics (SCP) method (Detect), 2) the development of disease experimental cell models and predictive computational models of cell trajectories (Understand), 3) the discovery of specific targets and personalized therapies (Cure), and 4) the creation of a community of collaborating laboratories to accelerate the development of this novel medical paradigm (Collaborate). A global initiative named 37TrillionCells (37TC) was launched to advance the development of cell-based interception and precision medicine.
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Affiliation(s)
- Benoit Coulombe
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada.
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, Canada.
| | - Thomas M Durcan
- The Neuro's Early Drug Discovery Unit (EDDU), McGill University, Montreal, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montreal, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Asmae Moursli
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
| | - Denis Faubert
- Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W1R7, Canada
| | - Maxime Pinard
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
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8
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Ruan DD, Ruan XL, Wang RL, Lin XF, Zhang YP, Lin B, Li SJ, Wu M, Chen Q, Zhang JH, Cheng Q, Zhang YW, Lin F, Luo JW, Zheng Z, Li YF. Clinical phenotype and genetic function analysis of a family with hypomyelinating leukodystrophy-7 caused by POLR3A mutation. Sci Rep 2024; 14:7638. [PMID: 38561452 PMCID: PMC10985069 DOI: 10.1038/s41598-024-58452-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/29/2024] [Indexed: 04/04/2024] Open
Abstract
Hypomyelinating leukodystrophy (HLD) is a rare genetic heterogeneous disease that can affect myelin development in the central nervous system. This study aims to analyze the clinical phenotype and genetic function of a family with HLD-7 caused by POLR3A mutation. The proband (IV6) in this family mainly showed progressive cognitive decline, dentin dysplasia, and hypogonadotropic hypogonadism. Her three old brothers (IV1, IV2, and IV4) also had different degrees of ataxia, dystonia, or dysarthria besides the aforementioned manifestations. Their brain magnetic resonance imaging showed bilateral periventricular white matter atrophy, brain atrophy, and corpus callosum atrophy and thinning. The proband and her two living brothers (IV2 and IV4) were detected to carry a homozygous mutation of the POLR3A (NM_007055.4) gene c. 2300G > T (p.Cys767Phe), and her consanguineous married parents (III1 and III2) were p.Cys767Phe heterozygous carriers. In the constructed POLR3A wild-type and p.Cys767Phe mutant cells, it was seen that overexpression of wild-type POLR3A protein significantly enhanced Pol III transcription of 5S rRNA and tRNA Leu-CAA. However, although the mutant POLR3A protein overexpression was increased compared to the wild-type protein overexpression, it did not show the expected further enhancement of Pol III function. On the contrary, Pol III transcription function was frustrated (POLR3A, BC200, and tRNA Leu-CAA expression decreased), and MBP and 18S rRNA expressions were decreased. This study indicates that the POLR3A p.Cys767Phe variant caused increased expression of mutated POLR3A protein and abnormal expression of Pol III transcripts, and the mutant POLR3A protein function was abnormal.
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Affiliation(s)
- Dan-Dan Ruan
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Xing-Lin Ruan
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Ruo-Li Wang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Fujian Provincial Key Laboratory of Emergency Medicine, Fujian Provincial Institute of Emergency Medicine, Fujian Emergency Medical Center, Fuzhou, 350001, China
| | - Xin-Fu Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Pediatrics Department, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yan-Ping Zhang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Bin Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Shi-Jie Li
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Min Wu
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Qian Chen
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Jian-Hui Zhang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Qiong Cheng
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yi-Wu Zhang
- Department of Neurology, Youxi County General Hospital, Sanming, 365100, China
| | - Fan Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Geriatric Medicine, Fujian Provincial Center for Geriatrics, Fujian Provincial Hospital, Fuzhou, 350001, China.
| | - Jie-Wei Luo
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
| | - Zheng Zheng
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China.
| | - Yun-Fei Li
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China.
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9
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Luo H, Lao L, Au KS, Northrup H, He X, Forget D, Gauthier MS, Coulombe B, Bourdeau I, Shi W, Gagliardi L, Fragoso MCBV, Peng J, Wu J. ARMC5 controls the degradation of most Pol II subunits, and ARMC5 mutation increases neural tube defect risks in mice and humans. Genome Biol 2024; 25:19. [PMID: 38225631 PMCID: PMC10789052 DOI: 10.1186/s13059-023-03147-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 12/18/2023] [Indexed: 01/17/2024] Open
Abstract
BACKGROUND Neural tube defects (NTDs) are caused by genetic and environmental factors. ARMC5 is part of a novel ubiquitin ligase specific for POLR2A, the largest subunit of RNA polymerase II (Pol II). RESULTS We find that ARMC5 knockout mice have increased incidence of NTDs, such as spina bifida and exencephaly. Surprisingly, the absence of ARMC5 causes the accumulation of not only POLR2A but also most of the other 11 Pol II subunits, indicating that the degradation of the whole Pol II complex is compromised. The enlarged Pol II pool does not lead to generalized Pol II stalling or a generalized decrease in mRNA transcription. In neural progenitor cells, ARMC5 knockout only dysregulates 106 genes, some of which are known to be involved in neural tube development. FOLH1, critical in folate uptake and hence neural tube development, is downregulated in the knockout intestine. We also identify nine deleterious mutations in the ARMC5 gene in 511 patients with myelomeningocele, a severe form of spina bifida. These mutations impair the interaction between ARMC5 and Pol II and reduce Pol II ubiquitination. CONCLUSIONS Mutations in ARMC5 increase the risk of NTDs in mice and humans. ARMC5 is part of an E3 controlling the degradation of all 12 subunits of Pol II under physiological conditions. The Pol II pool size might have effects on NTD pathogenesis, and some of the effects might be via the downregulation of FOLH1. Additional mechanistic work is needed to establish the causal effect of the findings on NTD pathogenesis.
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Affiliation(s)
- Hongyu Luo
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada.
| | - Linjiang Lao
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
| | - Kit Sing Au
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth) and Children's Memorial Hermann Hospital, Houston, TX, USA
| | - Hope Northrup
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth) and Children's Memorial Hermann Hospital, Houston, TX, USA
| | - Xiao He
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
| | - Diane Forget
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
| | - Marie-Soleil Gauthier
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
| | - Benoit Coulombe
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, Canada
| | - Isabelle Bourdeau
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
- Division of Endocrinology, CHUM, Montreal, QC, Canada
- Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Wei Shi
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
| | - Lucia Gagliardi
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, Australia
- Department of Genetics and Molecular Pathology, SA Pathology, Adelaide, Australia
- Endocrine and Diabetes Unit, Queen Elizabeth Hospital, Adelaide, Australia
| | - Maria Candida Barisson Villares Fragoso
- Unidade de Suprarrenal Disciplina de Endocrinologia E Metabologia, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Junzheng Peng
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
| | - Jiangping Wu
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada.
- Department of Medicine, Université de Montréal, Montreal, QC, Canada.
- Division of Nephrology, CHUM, Montreal, QC, Canada.
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10
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Mura E, Parazzini C, Tonduti D. Rare forms of hypomyelination and delayed myelination. HANDBOOK OF CLINICAL NEUROLOGY 2024; 204:225-252. [PMID: 39322381 DOI: 10.1016/b978-0-323-99209-1.00002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Hypomyelination is defined by the evidence of an unchanged pattern of deficient myelination on two MRIs performed at least 6 months apart in a child older than 1 year. When the temporal criteria are not fulfilled, and the follow-up MRI shows a progression of the myelination even if still not adequate for age, hypomyelination is excluded and the pattern is instead consistent with delayed myelination. This can be mild and nonspecific in some cases, while in other cases there is a severe delay that in the first disease stages could be difficult to differentiate from hypomyelination. In hypomyelinating leukodystrophies, hypomyelination is due to a primary impairment of myelin deposition, such as in Pelizaeus Merzabcher disease. Conversely, myelin lack is secondary, often to primary neuronal disorders, in delayed myelination and some condition with hypomyelination. Overall, the group of inherited white matter disorders with abnormal myelination has expanded significantly during the past 20 years. Many of these disorders have only recently been described, for many of them only a few patients have been reported and this contributes to make challenging the diagnostic process and the interpretation of Next Generation Sequencing results. In this chapter, we review the clinical and radiologic features of rare and lesser known forms of hypomyelination and delayed myelination not mentioned in other chapters of this handbook.
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Affiliation(s)
- Eleonora Mura
- Unit of Pediatric Neurology, Department of Biomedical and Clinical Sciences, V. Buzzi Children's Hospital, Università degli Studi di Milano, Milan, Italy; C.O.A.L.A (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Università degli Studi di Milano, Milan, Italy
| | - Cecilia Parazzini
- C.O.A.L.A (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Università degli Studi di Milano, Milan, Italy; Pediatric Radiology and Neuroradiology Department, V. Buzzi Children's Hospital, Milan, Italy
| | - Davide Tonduti
- Unit of Pediatric Neurology, Department of Biomedical and Clinical Sciences, V. Buzzi Children's Hospital, Università degli Studi di Milano, Milan, Italy; C.O.A.L.A (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Università degli Studi di Milano, Milan, Italy.
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11
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Perrier S, Gauquelin L, Bernard G. Inherited white matter disorders: Hypomyelination (myelin disorders). HANDBOOK OF CLINICAL NEUROLOGY 2024; 204:197-223. [PMID: 39322379 DOI: 10.1016/b978-0-323-99209-1.00014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Hypomyelinating leukodystrophies are a subset of genetic white matter diseases characterized by insufficient myelin deposition during development. MRI patterns are used to identify hypomyelinating disorders, and genetic testing is used to determine the causal genes implicated in individual disease forms. Clinical course can range from severe, with patients manifesting neurologic symptoms in infancy or early childhood, to mild, with onset in adolescence or adulthood. This chapter discusses the most common hypomyelinating leukodystrophies, including X-linked Pelizaeus-Merzbacher disease and other PLP1-related disorders, autosomal recessive Pelizaeus-Merzbacher-like disease, and POLR3-related leukodystrophy. PLP1-related disorders are caused by hemizygous pathogenic variants in the proteolipid protein 1 (PLP1) gene, and encompass classic Pelizaeus-Merzbacher disease, the severe connatal form, PLP1-null syndrome, spastic paraplegia type 2, and hypomyelination of early myelinating structures. Pelizaeus-Merzbacher-like disease presents a similar clinical picture to Pelizaeus-Merzbacher disease, however, it is caused by biallelic pathogenic variants in the GJC2 gene, which encodes for the gap junction protein Connexin-47. POLR3-related leukodystrophy, or 4H leukodystrophy (hypomyelination, hypodontia, and hypogonadotropic hypogonadism), is caused by biallelic pathogenic variants in genes encoding specific subunits of the transcription enzyme RNA polymerase III. In this chapter, the clinical features, disease pathophysiology and genetics, imaging patterns, as well as supportive and future therapies are discussed for each disorder.
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Affiliation(s)
- Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Laurence Gauquelin
- Division of Pediatric Neurology, Department of Pediatrics, CHUL et Centre Mère-Enfant Soleil du CHU de Québec-Université Laval, Québec, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada; Departments of Pediatrics and Human Genetics, McGill University, Montréal, QC, Canada.
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12
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Michell-Robinson MA, Watt KEN, Grouza V, Macintosh J, Pinard M, Tuznik M, Chen X, Darbelli L, Wu CL, Perrier S, Chitsaz D, Uccelli NA, Liu H, Cox TC, Müller CW, Kennedy TE, Coulombe B, Rudko DA, Trainor PA, Bernard G. Hypomyelination, hypodontia and craniofacial abnormalities in a Polr3b mouse model of leukodystrophy. Brain 2023; 146:5070-5085. [PMID: 37635302 PMCID: PMC10690025 DOI: 10.1093/brain/awad249] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 06/23/2023] [Accepted: 07/06/2023] [Indexed: 08/29/2023] Open
Abstract
RNA polymerase III (Pol III)-related hypomyelinating leukodystrophy (POLR3-HLD), also known as 4H leukodystrophy, is a severe neurodegenerative disease characterized by the cardinal features of hypomyelination, hypodontia and hypogonadotropic hypogonadism. POLR3-HLD is caused by biallelic pathogenic variants in genes encoding Pol III subunits. While approximately half of all patients carry mutations in POLR3B encoding the RNA polymerase III subunit B, there is no in vivo model of leukodystrophy based on mutation of this Pol III subunit. Here, we determined the impact of POLR3BΔ10 (Δ10) on Pol III in human cells and developed and characterized an inducible/conditional mouse model of leukodystrophy using the orthologous Δ10 mutation in mice. The molecular mechanism of Pol III dysfunction was determined in human cells by affinity purification-mass spectrometry and western blot. Postnatal induction with tamoxifen induced expression of the orthologous Δ10 hypomorph in triple transgenic Pdgfrα-Cre/ERT; R26-Stopfl-EYFP; Polr3bfl mice. CNS and non-CNS features were characterized using a variety of techniques including microCT, ex vivo MRI, immunofluorescence, immunohistochemistry, spectral confocal reflectance microscopy and western blot. Lineage tracing and time series analysis of oligodendrocyte subpopulation dynamics based on co-labelling with lineage-specific and/or proliferation markers were performed. Proteomics suggested that Δ10 causes a Pol III assembly defect, while western blots demonstrated reduced POLR3BΔ10 expression in the cytoplasm and nucleus in human cells. In mice, postnatal Pdgfrα-dependent expression of the orthologous murine mutant protein resulted in recessive phenotypes including severe hypomyelination leading to ataxia, tremor, seizures and limited survival, as well as hypodontia and craniofacial abnormalities. Hypomyelination was confirmed and characterized using classic methods to quantify myelin components such as myelin basic protein and lipids, results which agreed with those produced using modern methods to quantify myelin based on the physical properties of myelin membranes. Lineage tracing uncovered the underlying mechanism for the hypomyelinating phenotype: defective oligodendrocyte precursor proliferation and differentiation resulted in a failure to produce an adequate number of mature oligodendrocytes during postnatal myelinogenesis. In summary, we characterized the Polr3bΔ10 mutation and developed an animal model that recapitulates features of POLR3-HLD caused by POLR3B mutations, shedding light on disease pathogenesis, and opening the door to the development of therapeutic interventions.
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Affiliation(s)
- Mackenzie A Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Kristin E N Watt
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Vladimir Grouza
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Maxime Pinard
- Translational Proteomics Research Unit, Montreal Clinical Research Institute, Montréal, QC H2W 1R7, Canada
| | - Marius Tuznik
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Xiaoru Chen
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Lama Darbelli
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Chia-Lun Wu
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Daryan Chitsaz
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Nonthué A Uccelli
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Hanwen Liu
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Timothy C Cox
- Department of Oral and Craniofacial Sciences, School of Dentistry, and Pediatrics, School of Medicine, University of Missouri – Kansas City, Kansas City, MO 64108, USA
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Timothy E Kennedy
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Benoit Coulombe
- Translational Proteomics Research Unit, Montreal Clinical Research Institute, Montréal, QC H2W 1R7, Canada
- Department of Biochemistry and Molecular Medicine, University of Montréal, Montréal, QC H3C 3J7, Canada
| | - David A Rudko
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
- Department of Biomedical Engineering, McGill University, Montréal, QC H3A 2B4, Canada
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, KS 66160, USA
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- Department of Pediatrics, McGill University, Montréal, QC H4A 3J1, Canada
- Department of Human Genetics, McGill University, Montréal, QC H4A 0C7, Canada
- Department of Specialized Medicine, Division of Medical Genetics, Montreal Children’s Hospital and McGill University Health Centre, Montréal, QC H4A 3J1, Canada
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13
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Chapleau A, Mirchi A, Tran LT, Poulin C, Bernard G. Longitudinal Characterization of the Clinical Course of Intermediate-Severe Salla Disease. Pediatr Neurol 2023; 148:133-137. [PMID: 37713976 DOI: 10.1016/j.pediatrneurol.2023.08.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 06/21/2023] [Accepted: 08/13/2023] [Indexed: 09/17/2023]
Abstract
BACKGROUND Biallelic pathogenic variants in SLC17A5 cause three forms of free sialic acid storage disease categorized based on severity from least to most severe: Salla disease, intermediate-severe Salla disease, and infantile free sialic acid storage disease. Intermediate-severe Salla disease is the most recently described form. Here, we report a longitudinal characterization of intermediate-severe Salla disease progression in two sisters carrying the following biallelic variants in SLC17A5: c.406A>G (p.Lys136Glu) and c.819+1G>A. METHODS A retrospective review of medical records was performed. A developmental questionnaire was completed to obtain further clinical information. For functional characterization of the predicted splice site variant, RNA was extracted from patient blood samples and sequenced. RESULTS Disease onset occurred within the first six months of life in both patients. Early childhood development was delayed with achievement of some milestones followed by a developmental plateau in late childhood. After this, both patients began a slow and progressive neurological regression in adolescence. Functional studies confirmed the pathogenicity of the c.819+1G>A variant, resulting in a frameshift and deletion of exon 6. CONCLUSIONS We present a detailed study describing the clinical course of intermediate-severe Salla disease with over 15 to 20 years of evolution and demonstrate the pathogenicity of the c.819+1G>A splice site variant.
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Affiliation(s)
- Alexandra Chapleau
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
| | - Amytice Mirchi
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada; Department of Pediatrics, McGill University, Montréal, Canada
| | - Luan T Tran
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
| | - Chantal Poulin
- Department of Neurology and Neurosurgery, McGill University, Montréal, Canada; Department of Pediatrics, McGill University, Montréal, Canada
| | - Geneviève Bernard
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada; Department of Pediatrics, McGill University, Montréal, Canada; Department of Human Genetics, McGill University, Montréal, Canada; Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montréal, Canada.
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14
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Daiß JL, Griesenbeck J, Tschochner H, Engel C. Synthesis of the ribosomal RNA precursor in human cells: mechanisms, factors and regulation. Biol Chem 2023; 404:1003-1023. [PMID: 37454246 DOI: 10.1515/hsz-2023-0214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
The ribosomal RNA precursor (pre-rRNA) comprises three of the four ribosomal RNAs and is synthesized by RNA polymerase (Pol) I. Here, we describe the mechanisms of Pol I transcription in human cells with a focus on recent insights gained from structure-function analyses. The comparison of Pol I-specific structural and functional features with those of other Pols and with the excessively studied yeast system distinguishes organism-specific from general traits. We explain the organization of the genomic rDNA loci in human cells, describe the Pol I transcription cycle regarding structural changes in the enzyme and the roles of human Pol I subunits, and depict human rDNA transcription factors and their function on a mechanistic level. We disentangle information gained by direct investigation from what had apparently been deduced from studies of the yeast enzymes. Finally, we provide information about how Pol I mutations may contribute to developmental diseases, and why Pol I is a target for new cancer treatment strategies, since increased rRNA synthesis was correlated with rapidly expanding cell populations.
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Affiliation(s)
- Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Herbert Tschochner
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
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15
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Macintosh J, Perrier S, Pinard M, Tran LT, Guerrero K, Prasad C, Prasad AN, Pastinen T, Thiffault I, Coulombe B, Bernard G. Biallelic pathogenic variants in POLR3D alter tRNA transcription and cause a hypomyelinating leukodystrophy: A case report. Front Neurol 2023; 14:1254140. [PMID: 37915380 PMCID: PMC10616956 DOI: 10.3389/fneur.2023.1254140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
RNA polymerase III-related leukodystrophy (POLR3-related leukodystrophy) is a rare, genetically determined hypomyelinating disease arising from biallelic pathogenic variants in genes encoding subunits of RNA polymerase III (Pol III). Here, we describe the first reported case of POLR3-related leukodystrophy caused by biallelic pathogenic variants in POLR3D, encoding the RPC4 subunit of Pol III. The individual, a female, demonstrated delays in walking and expressive and receptive language as a child and later cognitively plateaued. Additional neurological features included cerebellar signs (e.g., dysarthria, ataxia, and intention tremor) and dysphagia, while non-neurological features included hypodontia, hypogonadotropic hypogonadism, and dysmorphic facial features. Her MRI was notable for diffuse hypomyelination with myelin preservation of early myelinating structures, characteristic of POLR3-related leukodystrophy. Exome sequencing revealed the biallelic variants in POLR3D, a missense variant (c.541C > T, p.P181S) and an intronic splice site variant (c.656-6G > A, p.?). Functional studies of the patient's fibroblasts demonstrated significantly decreased RNA-level expression of POLR3D, along with reduced expression of other Pol III subunit genes. Notably, Pol III transcription was also shown to be aberrant, with a significant decrease in 7SK RNA and several distinct tRNA genes analyzed. Affinity purification coupled to mass spectrometry of the POLR3D p.P181S variant showed normal assembly of Pol III subunits yet altered interaction of Pol III with the PAQosome chaperone complex, indicating the missense variant is likely to alter complex maturation. This work identifies biallelic pathogenic variants in POLR3D as a novel genetic cause of POLR3-related leukodystrophy, expanding the molecular spectrum associated with this disease, and proposes altered tRNA homeostasis as a factor in the underlying biology of this hypomyelinating disorder.
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Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Maxime Pinard
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
| | - Luan T. Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kether Guerrero
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Chitra Prasad
- Department of Pediatrics, London Health Sciences Center and Western University, London, ON, Canada
- Medical Genetics Program of Southwestern Ontario, London Health Sciences Center, London, ON, Canada
- Children’s Health Research Institute, London, ON, Canada
| | - Asuri N. Prasad
- Department of Pediatrics, London Health Sciences Center and Western University, London, ON, Canada
- Children’s Health Research Institute, London, ON, Canada
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, United States
| | - Benoit Coulombe
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montreal, QC, Canada
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16
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Mirchi A, Guay SP, Tran LT, Wolf NI, Vanderver A, Brais B, Sylvain M, Pohl D, Rossignol E, Saito M, Moutton S, González-Gutiérrez-Solana L, Thiffault I, Kruer MC, Moron DG, Kauffman M, Goizet C, Sztriha L, Glamuzina E, Melançon SB, Naidu S, Retrouvey JM, Lacombe S, Bernardino-Cuesta B, De Bie I, Bernard G. Craniofacial features of POLR3-related leukodystrophy caused by biallelic variants in POLR3A, POLR3B and POLR1C. J Med Genet 2023; 60:1026-1034. [PMID: 37197783 PMCID: PMC10579516 DOI: 10.1136/jmg-2023-109223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/16/2023] [Indexed: 05/19/2023]
Abstract
BACKGROUND RNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C or POLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants in POLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants in POLR3A, POLR3B and POLR1C are described. METHODS The craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype-phenotype associations were evaluated. RESULTS Various craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients with POLR3B biallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants in POLR3A and POLR3B while a higher proportion of patients with POLR1C biallelic variants demonstrated bitemporal narrowing. CONCLUSION Through this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants in POLR3A, POLR3B and POLR1C.
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Affiliation(s)
- Amytice Mirchi
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Simon-Pierre Guay
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
| | - Luan T Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, and Amsterdam Neuroscience, Cellular & Molecular Mechanisms, Vrije Universiteit, Amsterdam, Netherlands
| | - Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Michel Sylvain
- Centre Mère Enfant, CHU de Québec, Québec City, Quebec, Canada
| | - Daniela Pohl
- Division of Neurology, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario, Canada
| | - Elsa Rossignol
- Departments of Neurosciences and Pediatrics, CHU-Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Michael Saito
- Department of Pediatrics, University of California Riverside School of Medicine, Riverside Medical Clinic, Riverside, California, USA
| | - Sebastien Moutton
- Centre Pluridisciplinaire de Diagnostic PréNatal, MSPBordeaux Bagatelle, Talence, France
| | - Luis González-Gutiérrez-Solana
- Sección de Neuropediatría, Hospital Infantil Universitario Niño Jesús, Madrid, España; Grupo Clínico Vinculado al Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER) GCV14/ER/6, Hospital Infantil Universitario Nino Jesus, Madrid, Spain
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, Missouri, USA
- University of Missouri Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Michael C Kruer
- Departments of Child Health, Neurology, and Cellular & Molecular Medicine and Program in Genetics, University of Arizona College of Medicine, Phoenix, Arizona, USA
- Programs in Neuroscience and Molecular & Cellular Biology, School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Dolores Gonzales Moron
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia, ADC, Buenos Aires, Argentina
| | - Marcelo Kauffman
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia and CONICET-Universidad Austral, Buenos Aires, Argentina
| | - Cyril Goizet
- Centre de Référence Neurogénétique, Service de Génétique Médicale, Bordeaux University Hospital, CHU Bordeaux, Bordeaux, France
- NRGEN team, INCIA, CNRS UMR 5287, University of Bordeaux, Bordeaux, France
| | - László Sztriha
- Department of Paediatrics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic Service, Starship Children's Hospital, Auckland, Te Whatu Ora, New Zealand
| | - Serge B Melançon
- Department of Medical Genetics, McGill University Health Centre, Montreal Children's Hospital, Montreal, Quebec, Canada
| | - Sakkubai Naidu
- Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Jean-Marc Retrouvey
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | - Suzanne Lacombe
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | | | - Isabelle De Bie
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
- Department of Laboratory Medicine, McGill University Health Centre, Montreal, Quebec, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
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17
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Chapleau A, Boucher RM, Pastinen T, Thiffault I, Gould PV, Bernard G. Neuropathological characterization of the cavitating leukoencephalopathy caused by COA8 cytochrome c oxidase deficiency: a case report. Front Cell Neurosci 2023; 17:1216487. [PMID: 37601282 PMCID: PMC10436302 DOI: 10.3389/fncel.2023.1216487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
COA8-related leukoencephalopathy is a recently described rare cavitating leukoencephalopathy caused by biallelic variants in the COA8 gene. Clinically, it presents heterogeneously and usually follows a bi-phasic clinical course with a period of acute onset and regression, followed by stabilization, and in some cases, even subtle improvement. We present a 4-year-old boy with a homozygous 2.5 kilobase pair deletion in the COA8 gene following a severe neurological deterioration resulting in death weeks after onset. Brain MRI revealed a distinctive pattern of cavitating leukodystrophy predominantly involving the posterior cerebral white matter which improved upon a follow-up MRI a month later. Brain pathology displayed overall white matter destruction with gliosis and infiltration by macrophages. There was preservation of astrocytes around blood vessels and axons around the zones of demyelination. This study is the first neuropathological examination of COA8-related leukoencephalopathy and provides further characterization of the clinical and MRI phenotype.
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Affiliation(s)
- Alexandra Chapleau
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Renée-Myriam Boucher
- Centre Hospitalier Universitaire de Québec-Université Laval, Québec City, QC, Canada
| | - Tomi Pastinen
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, United States
- Kansas City School of Medicine, University of Missouri, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children’s Mercy Hospital, Kansas City, MO, United States
- Kansas City School of Medicine, University of Missouri, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital, Kansas City, MO, United States
| | - Peter V. Gould
- Service d’anatomopathologie Hôpital de l’Enfant-Jésus du CHU de Québec-Université Laval, Québec City, QC, Canada
| | - Geneviève Bernard
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre, Montreal, QC, Canada
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18
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Cai X, Stringer JM, Zerafa N, Carroll J, Hutt KJ. Xrcc5/Ku80 is required for the repair of DNA damage in fully grown meiotically arrested mammalian oocytes. Cell Death Dis 2023; 14:397. [PMID: 37407587 DOI: 10.1038/s41419-023-05886-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 05/07/2023] [Accepted: 06/12/2023] [Indexed: 07/07/2023]
Abstract
Mammalian oocytes spend most of their life in a unique state of cell cycle arrest at meiotic prophase I, during which time they are exposed to countless DNA-damaging events. Recent studies have shown that DNA double-strand break repair occurs predominantly via the homologous recombination (HR) pathway in small non-growing meiotically arrested oocytes (primordial follicle stage). However, the DNA repair mechanisms employed by fully grown meiotically arrested oocytes (GV-stage) have not been studied in detail. Here we established a conditional knockout mouse model to explore the role of Ku80, a critical component of the nonhomologous end joining (NHEJ) pathway, in the repair of DNA damage in GV oocytes. GV oocytes lacking Ku80 failed to repair etoposide-induced DNA damage, even when only low levels of damage were sustained. This indicates Ku80 is needed to resolve DSBs and that HR cannot compensate for a compromised NHEJ pathway in fully-grown oocytes. When higher levels of DNA damage were induced, a severe delay in M-phase entry was observed in oocytes lacking XRCC5 compared to wild-type oocytes, suggesting that Ku80-dependent repair of DNA damage is important for the timely release of oocytes from prophase I and resumption of meiosis. Ku80 was also found to be critical for chromosome integrity during meiotic maturation following etoposide exposure. These data demonstrate that Ku80, and NHEJ, are vital for quality control in mammalian GV stage oocytes and reveal that DNA repair pathway choice differs in meiotically arrested oocytes according to growth status.
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Affiliation(s)
- Xuebi Cai
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Jessica M Stringer
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Nadeen Zerafa
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - John Carroll
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Karla J Hutt
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
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19
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Belkevich AE, Pascual HG, Fakhouri AM, Ball DG, Knutson BA. Distinct Interaction Modes for the Eukaryotic RNA Polymerase Alpha-like Subunits. Mol Cell Biol 2023; 43:269-282. [PMID: 37222571 PMCID: PMC10251799 DOI: 10.1080/10985549.2023.2210023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/26/2023] [Accepted: 04/12/2023] [Indexed: 05/25/2023] Open
Abstract
Eukaryotic DNA-dependent RNA polymerases (Pols I-III) encode two distinct alpha-like heterodimers where one is shared between Pols I and III, and the other is unique to Pol II. Human alpha-like subunit mutations are associated with several diseases including Treacher Collins Syndrome (TCS), 4H leukodystrophy, and primary ovarian sufficiency. Yeast is commonly used to model human disease mutations, yet it remains unclear whether the alpha-like subunit interactions are functionally similar between yeast and human homologs. To examine this, we mutated several regions of the yeast and human small alpha-like subunits and used biochemical and genetic assays to establish the regions and residues required for heterodimerization with their corresponding large alpha-like subunits. Here we show that different regions of the small alpha-like subunits serve differential roles in heterodimerization, in a polymerase- and species-specific manner. We found that the small human alpha-like subunits are more sensitive to mutations, including a "humanized" yeast that we used to characterize the molecular consequence of the TCS-causingPOLR1D G52E mutation. These findings help explain why some alpha subunit associated disease mutations have little to no effect when made in their yeast orthologs and offer a better yeast model to assess the molecular basis of POLR1D associated disease mutations.
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Affiliation(s)
- Alana E. Belkevich
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Haleigh G. Pascual
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Aula M. Fakhouri
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - David G. Ball
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Bruce A. Knutson
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
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20
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Smallwood K, Watt KEN, Ide S, Baltrunaite K, Brunswick C, Inskeep K, Capannari C, Adam MP, Begtrup A, Bertola DR, Demmer L, Demo E, Devinsky O, Gallagher ER, Guillen Sacoto MJ, Jech R, Keren B, Kussmann J, Ladda R, Lansdon LA, Lunke S, Mardy A, McWalters K, Person R, Raiti L, Saitoh N, Saunders CJ, Schnur R, Skorvanek M, Sell SL, Slavotinek A, Sullivan BR, Stark Z, Symonds JD, Wenger T, Weber S, Whalen S, White SM, Winkelmann J, Zech M, Zeidler S, Maeshima K, Stottmann RW, Trainor PA, Weaver KN. POLR1A variants underlie phenotypic heterogeneity in craniofacial, neural, and cardiac anomalies. Am J Hum Genet 2023; 110:809-825. [PMID: 37075751 PMCID: PMC10183370 DOI: 10.1016/j.ajhg.2023.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/21/2023] [Indexed: 04/21/2023] Open
Abstract
Heterozygous pathogenic variants in POLR1A, which encodes the largest subunit of RNA Polymerase I, were previously identified as the cause of acrofacial dysostosis, Cincinnati-type. The predominant phenotypes observed in the cohort of 3 individuals were craniofacial anomalies reminiscent of Treacher Collins syndrome. We subsequently identified 17 additional individuals with 12 unique heterozygous variants in POLR1A and observed numerous additional phenotypes including neurodevelopmental abnormalities and structural cardiac defects, in combination with highly prevalent craniofacial anomalies and variable limb defects. To understand the pathogenesis of this pleiotropy, we modeled an allelic series of POLR1A variants in vitro and in vivo. In vitro assessments demonstrate variable effects of individual pathogenic variants on ribosomal RNA synthesis and nucleolar morphology, which supports the possibility of variant-specific phenotypic effects in affected individuals. To further explore variant-specific effects in vivo, we used CRISPR-Cas9 gene editing to recapitulate two human variants in mice. Additionally, spatiotemporal requirements for Polr1a in developmental lineages contributing to congenital anomalies in affected individuals were examined via conditional mutagenesis in neural crest cells (face and heart), the second heart field (cardiac outflow tract and right ventricle), and forebrain precursors in mice. Consistent with its ubiquitous role in the essential function of ribosome biogenesis, we observed that loss of Polr1a in any of these lineages causes cell-autonomous apoptosis resulting in embryonic malformations. Altogether, our work greatly expands the phenotype of human POLR1A-related disorders and demonstrates variant-specific effects that provide insights into the underlying pathogenesis of ribosomopathies.
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Affiliation(s)
- Kelly Smallwood
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | | | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan; Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, Japan
| | - Kristina Baltrunaite
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Chad Brunswick
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Katherine Inskeep
- Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Corrine Capannari
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Margaret P Adam
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | | | - Laurie Demmer
- Atrium Health's Levine Children's Hospital, Charlotte, NC, USA
| | - Erin Demo
- Sibley Heart Center, Atlanta, GA, USA
| | - Orrin Devinsky
- Department of Neurology, Comprehensive Epilepsy Center, New York University Grossman School of Medicine, New York, NY, USA
| | - Emily R Gallagher
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Robert Jech
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Boris Keren
- Genetic Department, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 47-83 Boulevard de l'Hôpital, 75013 Paris, France
| | - Jennifer Kussmann
- Division of Clinical Genetics, Department of Pediatrics, Children's Mercy Kansas City, 2401 Gillham Road, Kansas City, MO, USA
| | - Roger Ladda
- Department of Pediatrics, Penn State Health Children's Hospital, Hershey, PA, USA
| | - Lisa A Lansdon
- Department of Pathology and Laboratory Medicine, Children's Mercy Kansas City, 2401 Gillham Road, Kansas City, MO, USA; Genomic Medicine Center, Children's Mercy Research Institute, 2401 Gillham Road, Kansas City, MO, USA; School of Medicine, University of Missouri-Kansas City, 2411 Holmes Street, Kansas City, MO, USA
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Flemington Road, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia; Australian Genomics, Melbourne, VIC, Australia
| | - Anne Mardy
- Department of Women's Health, University of Texas Austin Dell Medical Center, Austin, TX, USA
| | | | | | - Laura Raiti
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Flemington Road, Melbourne, VIC, Australia
| | | | - Carol J Saunders
- Department of Pathology and Laboratory Medicine, Children's Mercy Kansas City, 2401 Gillham Road, Kansas City, MO, USA; Genomic Medicine Center, Children's Mercy Research Institute, 2401 Gillham Road, Kansas City, MO, USA; School of Medicine, University of Missouri-Kansas City, 2411 Holmes Street, Kansas City, MO, USA
| | | | - Matej Skorvanek
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic; Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Susan L Sell
- Department of Pediatrics, Penn State Health Children's Hospital, Hershey, PA, USA
| | - Anne Slavotinek
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Bonnie R Sullivan
- Division of Clinical Genetics, Department of Pediatrics, Children's Mercy Kansas City, 2401 Gillham Road, Kansas City, MO, USA
| | - Zornitza Stark
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Flemington Road, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia; Australian Genomics, Melbourne, VIC, Australia
| | - Joseph D Symonds
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow G667AB, UK
| | - Tara Wenger
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Sacha Weber
- CCA-AHU de génétique clinique et de neurogénétique, Service de Génétique et de Neurologie, CHU de Caen, Caen, France
| | - Sandra Whalen
- Genetic Department, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 47-83 Boulevard de l'Hôpital, 75013 Paris, France
| | - Susan M White
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Flemington Road, Melbourne, VIC, Australia; University of Melbourne, Melbourne, VIC, Australia
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany; Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany; Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Shimriet Zeidler
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan; Department of Genetics, School of Life Science, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, Japan
| | - Rolf W Stottmann
- Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University School of Medicine, Columbus, OH, USA
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - K Nicole Weaver
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Macintosh J, Michell-Robinson M, Chen X, Bernard G. Decreased RNA polymerase III subunit expression leads to defects in oligodendrocyte development. Front Neurosci 2023; 17:1167047. [PMID: 37179550 PMCID: PMC10167296 DOI: 10.3389/fnins.2023.1167047] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 03/31/2023] [Indexed: 05/15/2023] Open
Abstract
Introduction RNA polymerase III (Pol III) is a critical enzymatic complex tasked with the transcription of ubiquitous non-coding RNAs including 5S rRNA and all tRNA genes. Despite the constitutive nature of this enzyme, hypomorphic biallelic pathogenic variants in genes encoding subunits of Pol III lead to tissue-specific features and cause a hypomyelinating leukodystrophy, characterized by a severe and permanent deficit in myelin. The pathophysiological mechanisms in POLR3- related leukodystrophy and specifically, how reduced Pol III function impacts oligodendrocyte development to account for the devastating hypomyelination seen in the disease, remain poorly understood. Methods In this study, we characterize how reducing endogenous transcript levels of leukodystrophy-associated Pol III subunits affects oligodendrocyte maturation at the level of their migration, proliferation, differentiation, and myelination. Results Our results show that decreasing Pol III expression altered the proliferation rate of oligodendrocyte precursor cells but had no impact on migration. Additionally, reducing Pol III activity impaired the differentiation of these precursor cells into mature oligodendrocytes, evident at both the level of OL-lineage marker expression and on morphological assessment, with Pol III knockdown cells displaying a drastically more immature branching complexity. Myelination was hindered in the Pol III knockdown cells, as determined in both organotypic shiverer slice cultures and co-cultures with nanofibers. Analysis of Pol III transcriptional activity revealed a decrease in the expression of distinct tRNAs, which was significant in the siPolr3a condition. Discussion In turn, our findings provide insight into the role of Pol III in oligodendrocyte development and shed light on the pathophysiological mechanisms of hypomyelination in POLR3-related leukodystrophy.
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Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Mackenzie Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Xiaoru Chen
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
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22
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Watt KE, Macintosh J, Bernard G, Trainor PA. RNA Polymerases I and III in development and disease. Semin Cell Dev Biol 2023; 136:49-63. [PMID: 35422389 PMCID: PMC9550887 DOI: 10.1016/j.semcdb.2022.03.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 12/18/2022]
Abstract
Ribosomes are macromolecular machines that are globally required for the translation of all proteins in all cells. Ribosome biogenesis, which is essential for cell growth, proliferation and survival, commences with transcription of a variety of RNAs by RNA Polymerases I and III. RNA Polymerase I (Pol I) transcribes ribosomal RNA (rRNA), while RNA Polymerase III (Pol III) transcribes 5S ribosomal RNA and transfer RNAs (tRNA) in addition to a wide variety of small non-coding RNAs. Interestingly, despite their global importance, disruptions in Pol I and Pol III function result in tissue-specific developmental disorders, with craniofacial anomalies and leukodystrophy/neurodegenerative disease being among the most prevalent. Furthermore, pathogenic variants in genes encoding subunits shared between Pol I and Pol III give rise to distinct syndromes depending on whether Pol I or Pol III function is disrupted. In this review, we discuss the global roles of Pol I and III transcription, the consequences of disruptions in Pol I and III transcription, disorders arising from pathogenic variants in Pol I and Pol III subunits, and mechanisms underpinning their tissue-specific phenotypes.
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Affiliation(s)
- Kristin En Watt
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada; Departments of Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada; Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada.
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA.
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23
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Regulation of ribosomal RNA gene copy number, transcription and nucleolus organization in eukaryotes. Nat Rev Mol Cell Biol 2023; 24:414-429. [PMID: 36732602 DOI: 10.1038/s41580-022-00573-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2022] [Indexed: 02/04/2023]
Abstract
One of the first biological machineries to be created seems to have been the ribosome. Since then, organisms have dedicated great efforts to optimize this apparatus. The ribosomal RNA (rRNA) contained within ribosomes is crucial for protein synthesis and maintenance of cellular function in all known organisms. In eukaryotic cells, rRNA is produced from ribosomal DNA clusters of tandem rRNA genes, whose organization in the nucleolus, maintenance and transcription are strictly regulated to satisfy the substantial demand for rRNA required for ribosome biogenesis. Recent studies have elucidated mechanisms underlying the integrity of ribosomal DNA and regulation of its transcription, including epigenetic mechanisms and a unique recombination and copy-number control system to stably maintain high rRNA gene copy number. In this Review, we disucss how the crucial maintenance of rRNA gene copy number through control of gene amplification and of rRNA production by RNA polymerase I are orchestrated. We also discuss how liquid-liquid phase separation controls the architecture and function of the nucleolus and the relationship between rRNA production, cell senescence and disease.
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24
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Lactobacillus for ribosome peptide editing cancer. Clin Transl Oncol 2023; 25:1522-1544. [PMID: 36694080 PMCID: PMC9873400 DOI: 10.1007/s12094-022-03066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/24/2022] [Indexed: 01/25/2023]
Abstract
This study reviews newly discovered insect peptide point mutations as new possible cancer research targets. To interpret newly discovered peptide point mutations in insects as new possible cancer research targets, we focused on the numerous peptide changes found in the 'CSP' family on the sex pheromone gland of the female silkworm moth Bombyx mori. We predict that the Bombyx peptide modifications will have a significant effect on cancer CUP (cancers of unknown primary) therapy and that bacterial peptide editing techniques, specifically Lactobacillus combined to CRISPR, will be used to regulate ribosomes and treat cancer in humans.
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25
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circPOLR1C Promotes the Development of Esophageal Cancer by Adsorbing miR-361-3p and Regulating Cancer Cell Apoptosis and Metastasis. JOURNAL OF ONCOLOGY 2022; 2022:9124142. [PMID: 36590309 PMCID: PMC9803566 DOI: 10.1155/2022/9124142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 11/22/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Background The effect of circular RNA-RNA polymerase I and III subunit C (circPOLR1C) on esophageal cancer (EC) has not been reported. Herein, this study is designed to unveil the effect and the regulatory mechanism of circPOLR1C on EC. Methods The expression of circPOLR1C in EC tissues and cells was detected by qRT-PCR. Circular structure, stability, and cell localization of circPOLR1C were confirmed by qRT-PCR, RNase R, actinomycin D, and fluorescence in situ hybridization (FISH) assay. Cell function experiments, nude mouse xenograft, lung transplant model, and HE staining were performed to evaluate the effects of CircPOLR1C on EC in vitro and in vivo. A regulatory relationship between miR-361-3p and circPOLR1C was confirmed by qRT-PCR, circRNA in vivo precipitation, RIP, FISH, CircInteractome database, dual-luciferase reporter assay, and immunohistochemistry. Rescue experiments were applied to assess the effects of miR-361-3p and circPOLR1C on EC cells and tissues. Apoptosis- and epithelial-mesenchymal transformation (EMT)-related gene expressions were quantified by qRT-PCR and Western blot. Results Highly expressed circPOLR1C in EC was related to tumor differentiation and invasion. circPOLR1C, which mainly exists in the cytoplasm, is a stable circular RNA. circPOLR1C silencing inhibited circPOLR1C expression and EC cell malignant function, while circPOLR1C overexpression promoted the growth of transplanted tumors and lung metastasis. The enrichment of miR-361-3p was higher than that of other targeted miRNAs. circPOLR1C adsorbed miR-361-3p to regulate apoptosis- and EMT-related genes and partially reversed the tumor suppressive effect of miR-361-3p, which was lowly expressed in EC tissues. Silencing the target genes of miR-361-3p also inhibited the malignant development of EC cells. Conclusion circPOLR1C adsorbs miR-361-3p and regulates apoptosis- and EMT-related gene expressions to promote the development of EC.
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26
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Leucoencefalopatie ereditarie e leucodistrofie dell’adulto. Neurologia 2022. [DOI: 10.1016/s1634-7072(22)47096-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
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Pinard M, Dastpeyman S, Poitras C, Bernard G, Gauthier MS, Coulombe B. Riluzole partially restores RNA polymerase III complex assembly in cells expressing the leukodystrophy-causative variant POLR3B R103H. Mol Brain 2022; 15:98. [PMID: 36451185 PMCID: PMC9710144 DOI: 10.1186/s13041-022-00974-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/16/2022] [Indexed: 12/12/2022] Open
Abstract
The mechanism of assembly of RNA polymerase III (Pol III), the 17-subunit enzyme that synthesizes tRNAs, 5 S rRNA, and other small-nuclear (sn) RNAs in eukaryotes, is not clearly understood. The recent discovery of the HSP90 co-chaperone PAQosome (Particle for Arrangement of Quaternary structure) revealed a function for this machinery in the biogenesis of nuclear RNA polymerases. However, the connection between Pol III subunits and the PAQosome during the assembly process remains unexplored. Here, we report the development of a mass spectrometry-based assay that allows the characterization of Pol III assembly. This assay was used to dissect the stages of Pol III assembly, to start defining the function of the PAQosome in this process, to dissect the assembly defects driven by the leukodystrophy-causative R103H substitution in POLR3B, and to discover that riluzole, an FDA-approved drug for alleviation of ALS symptoms, partly corrects these assembly defects. Together, these results shed new light on the mechanism and regulation of human nuclear Pol III biogenesis.
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Affiliation(s)
- Maxime Pinard
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Samaneh Dastpeyman
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Christian Poitras
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Geneviève Bernard
- grid.63984.300000 0000 9064 4811Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Neurology and Neurosurgery, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Human Genetics, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Pediatrics, McGill University, Montreal, Canada ,grid.63984.300000 0000 9064 4811Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada
| | - Marie-Soleil Gauthier
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Benoit Coulombe
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada ,grid.14848.310000 0001 2292 3357Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec Canada
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28
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Jiang Y, Huang J, Tian K, Yi X, Zheng H, Zhu Y, Guo T, Ji X. Cross-regulome profiling of RNA polymerases highlights the regulatory role of polymerase III on mRNA transcription by maintaining local chromatin architecture. Genome Biol 2022; 23:246. [PMID: 36443871 PMCID: PMC9703767 DOI: 10.1186/s13059-022-02812-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Mammalian cells have three types of RNA polymerases (Pols), Pol I, II, and III. However, the extent to which these polymerases are cross-regulated and the underlying mechanisms remain unclear. RESULTS We employ genome-wide profiling after acute depletion of Pol I, Pol II, or Pol III to assess cross-regulatory effects between these Pols. We find that these enzymes mainly affect the transcription of their own target genes, while certain genes are transcribed by the other polymerases. Importantly, the most active type of crosstalk is exemplified by the fact that Pol III depletion affects Pol II transcription. Pol II genes with transcription changes upon Pol III depletion are enriched in diverse cellular functions, and Pol III binding sites are found near their promoters. However, these Pol III binding sites do not correspond to transfer RNAs. Moreover, we demonstrate that Pol III regulates Pol II transcription and chromatin binding of the facilitates chromatin transcription (FACT) complex to alter local chromatin structures, which in turn affects the Pol II transcription rate. CONCLUSIONS Our results support a model suggesting that RNA polymerases show cross-regulatory effects: Pol III affects local chromatin structures and the FACT-Pol II axis to regulate the Pol II transcription rate at certain gene loci. This study provides a new perspective for understanding the dysregulation of Pol III in various tissues affected by developmental diseases.
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Affiliation(s)
- Yongpeng Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Kai Tian
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Xiao Yi
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Westlake Omics (Hangzhou) Biotechnology Co., Ltd, Hangzhou, 310024, China
| | - Haonan Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Yi Zhu
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Westlake Omics (Hangzhou) Biotechnology Co., Ltd, Hangzhou, 310024, China
| | - Tiannan Guo
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
- Westlake Omics (Hangzhou) Biotechnology Co., Ltd, Hangzhou, 310024, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
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29
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Daiß JL, Pilsl M, Straub K, Bleckmann A, Höcherl M, Heiss FB, Abascal-Palacios G, Ramsay EP, Tlučková K, Mars JC, Fürtges T, Bruckmann A, Rudack T, Bernecky C, Lamour V, Panov K, Vannini A, Moss T, Engel C. The human RNA polymerase I structure reveals an HMG-like docking domain specific to metazoans. Life Sci Alliance 2022; 5:5/11/e202201568. [PMID: 36271492 PMCID: PMC9438803 DOI: 10.26508/lsa.202201568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 06/20/2022] [Accepted: 08/09/2022] [Indexed: 11/24/2022] Open
Abstract
We characterize the human RNA polymerase I by evolutionary biochemistry and cryo-EM revealing a built-in structural domain that apparently serves as transcription factor–binding platform in metazoans. Transcription of the ribosomal RNA precursor by RNA polymerase (Pol) I is a major determinant of cellular growth, and dysregulation is observed in many cancer types. Here, we present the purification of human Pol I from cells carrying a genomic GFP fusion on the largest subunit allowing the structural and functional analysis of the enzyme across species. In contrast to yeast, human Pol I carries a single-subunit stalk, and in vitro transcription indicates a reduced proofreading activity. Determination of the human Pol I cryo-EM reconstruction in a close-to-native state rationalizes the effects of disease-associated mutations and uncovers an additional domain that is built into the sequence of Pol I subunit RPA1. This “dock II” domain resembles a truncated HMG box incapable of DNA binding which may serve as a downstream transcription factor–binding platform in metazoans. Biochemical analysis, in situ modelling, and ChIP data indicate that Topoisomerase 2a can be recruited to Pol I via the domain and cooperates with the HMG box domain–containing factor UBF. These adaptations of the metazoan Pol I transcription system may allow efficient release of positive DNA supercoils accumulating downstream of the transcription bubble.
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Affiliation(s)
- Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Michael Pilsl
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Kristina Straub
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Andrea Bleckmann
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Mona Höcherl
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Florian B Heiss
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Guillermo Abascal-Palacios
- Division of Structural Biology, The Institute of Cancer Research, London, UK
- Biofisika Institute (CSIC, UPV/EHU), Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Ewan P Ramsay
- Division of Structural Biology, The Institute of Cancer Research, London, UK
- Fondazione Human Technopole, Structural Biology Research Centre, Milan, Italy
| | | | - Jean-Clement Mars
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec, Canada
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
- Borden Laboratory, IRIC, Université de Montréal, Montréal, Québec, Canada
| | - Torben Fürtges
- Protein Crystallography, Department of Biophysics, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Astrid Bruckmann
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Till Rudack
- Protein Crystallography, Department of Biophysics, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Carrie Bernecky
- Institute of Science and Technology, Klosterneuburg, Austria
| | - Valérie Lamour
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of Integrated Structural Biology, Illkirch, France
- Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Konstantin Panov
- School of Biological Sciences and PGJCCR, Queen’s University Belfast, Belfast, UK
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London, UK
- Fondazione Human Technopole, Structural Biology Research Centre, Milan, Italy
| | - Tom Moss
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec, Canada
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
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30
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Abstract
tRNAs are key adaptor molecules that decipher the genetic code during translation of mRNAs in protein synthesis. In contrast to the traditional view of tRNAs as ubiquitously expressed housekeeping molecules, awareness is now growing that tRNA-encoding genes display tissue-specific and cell type-specific patterns of expression, and that tRNA gene expression and function are both dynamically regulated by post-transcriptional RNA modifications. Moreover, dysregulation of tRNAs, mediated by alterations in either their abundance or function, can have deleterious consequences that contribute to several distinct human diseases, including neurological disorders and cancer. Accumulating evidence shows that reprogramming of mRNA translation through altered tRNA activity can drive pathological processes in a codon-dependent manner. This Review considers the emerging evidence in support of the precise control of functional tRNA levels as an important regulatory mechanism that coordinates mRNA translation and protein expression in physiological cell homeostasis, and highlights key examples of human diseases that are linked directly to tRNA dysregulation.
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Affiliation(s)
- Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Elisabeth Siegal
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
- Harvard Initiative for RNA Medicine, Harvard University, Boston, MA, USA.
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31
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Peng Q, Zhang Y, Xian B, Wu L, Ding J, Ding W, Zhang X, Ding B, Li D, Wu J, Hu X, Lu G. A synonymous variant contributes to a rare Wiedemann-Rautenstrauch syndrome complicated with mild anemia via affecting pre-mRNA splicing. Front Mol Neurosci 2022; 15:1026530. [DOI: 10.3389/fnmol.2022.1026530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Wiedemann-Rautenstrauch syndrome (WDRTS) is an extremely rare autosomal recessive neonatal disorder. Currently, over 50 cases with variable phenotypes of WDRTS have been reported. In our cohort of prenatal and postnatal growth retardation, a female proband was found to have general growth retardation, neurocutaneous syndrome, and anemia. Karyotype test and array-CGH detected no obvious chromosomal aberrations. Trio-based whole-exome sequencing (Trio-WES) identified bi-allelic compound mutations in the coding sequence (CDS) of POLR3A gene (c.3342C > T, p.Ser1114 = and c.3718G > A, p.Gly1240Ser). For the mild anemia phenotype, the underlying causal genetic factors could be attributed to the compound heterozygous mutations in FANCA gene (c.2832dup, p.Ala945CysfsTer6 and c.1902 T > G, p.Asp634Glu). Mini-gene reporter assays revealed that the synonymous variant of POLR3A and the missense variant of FANCA could affect pre-mRNA splicing of each gene. For POLR3A, the synonymous mutation (c.3342C > T, p.Ser1114=) generated three types of aberrant isoforms. Therefore, the female patient was finally diagnosed as WDRTS caused by POLR3A. For FANCA, the missense variant (c.1902 T > G, p.Asp634Glu) disrupted the normal splicing between exon 21 and 22, and produced two types of abnormal isoforms, one carrying the 1902G and the other spliced between exon 21 and 23 to exclude exon 22. Network analysis showed that POLR3A and FANCA could be STRINGed, indicating both proteins might collaborate for some unknown functions. Current investigation would broaden the knowledge for clinicians and genetic counselors and remind them to interpret those synonymous or predicted “benign” variants more carefully.
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32
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Falcon KT, Watt KEN, Dash S, Zhao R, Sakai D, Moore EL, Fitriasari S, Childers M, Sardiu ME, Swanson S, Tsuchiya D, Unruh J, Bugarinovic G, Li L, Shiang R, Achilleos A, Dixon J, Dixon MJ, Trainor PA. Dynamic regulation and requirement for ribosomal RNA transcription during mammalian development. Proc Natl Acad Sci U S A 2022; 119:e2116974119. [PMID: 35881792 PMCID: PMC9351356 DOI: 10.1073/pnas.2116974119] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 05/11/2022] [Indexed: 01/28/2023] Open
Abstract
Ribosomal RNA (rRNA) transcription by RNA polymerase I (Pol I) is a critical rate-limiting step in ribosome biogenesis, which is essential for cell survival. Despite its global function, disruptions in ribosome biogenesis cause tissue-specific birth defects called ribosomopathies, which frequently affect craniofacial development. Here, we describe a cellular and molecular mechanism underlying the susceptibility of craniofacial development to disruptions in Pol I transcription. We show that Pol I subunits are highly expressed in the neuroepithelium and neural crest cells (NCCs), which generate most of the craniofacial skeleton. High expression of Pol I subunits sustains elevated rRNA transcription in NCC progenitors, which supports their high tissue-specific levels of protein translation, but also makes NCCs particularly sensitive to rRNA synthesis defects. Consistent with this model, NCC-specific deletion of Pol I subunits Polr1a, Polr1c, and associated factor Tcof1 in mice cell-autonomously diminishes rRNA synthesis, which leads to p53 protein accumulation, resulting in NCC apoptosis and craniofacial anomalies. Furthermore, compound mutations in Pol I subunits and associated factors specifically exacerbate the craniofacial anomalies characteristic of the ribosomopathies Treacher Collins syndrome and Acrofacial Dysostosis-Cincinnati type. Mechanistically, we demonstrate that diminished rRNA synthesis causes an imbalance between rRNA and ribosomal proteins. This leads to increased binding of ribosomal proteins Rpl5 and Rpl11 to Mdm2 and concomitantly diminished binding between Mdm2 and p53. Altogether, our results demonstrate a dynamic spatiotemporal requirement for rRNA transcription during mammalian cranial NCC development and corresponding tissue-specific threshold sensitivities to disruptions in rRNA transcription in the pathogenesis of congenital craniofacial disorders.
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Affiliation(s)
- Karla T. Falcon
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | | | - Soma Dash
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Ruonan Zhao
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160
| | - Daisuke Sakai
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Biology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan
| | - Emma L. Moore
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | | | | | - Mihaela E. Sardiu
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Biostatistics and Data Science, University of Kansas Medical Center, Kansas City, KS 66160
| | - Selene Swanson
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Dai Tsuchiya
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Jay Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - George Bugarinovic
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Orthopedic Surgery, Stanford University, Stanford, CA 94305
| | - Lin Li
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23284
| | - Rita Shiang
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23284
| | - Annita Achilleos
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Basic and Clinical Sciences, University of Nicosia Medical School, Nicosia 2408, Cyprus
| | - Jill Dixon
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Michael J. Dixon
- Faculty of Biology, Medicine, and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Paul A. Trainor
- Stowers Institute for Medical Research, Kansas City, MO 64110
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160
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33
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Yoon Han J, Gon Cho Y, Park J, Jang W. A novel variant of the POLR3A gene in a patient with hypomyelinating POLR3-related leukodystrophy. Clin Chim Acta 2022; 533:15-21. [PMID: 35691411 DOI: 10.1016/j.cca.2022.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/04/2022] [Accepted: 06/05/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hypomyelinating POLR3-related leukodystrophy is a group of rare neurological diseases characterized by degeneration of the white matter of the brain with different combinations of major clinical findings. Here we report the first Korean POLR3-related leukodystrophy caused by bi-allelic POLR3A c.1771-6C > G and novel c.1650_1661del variants. METHODS An 18-month-old girl was admitted for evaluation of a seizure-like activity with spasticity that affected her entire body. She showed dental abnormalities, but not suspicious facial dysmorphism. She was in a bed-ridden state with severe cognitive impairments and episodes of dystonic posturing for 1-2 min. Trio exome sequencing (ES) was performed to determine the potential genetic cause of severe developmental delay with leukodystrophy in our proband. RESULTS Trio ES revealed that bi-allelic POLR3A deleterious variants, c.1650_1661del of the exon 13, and c.1771-6C > G of the intron 13 were best candidate as causes of hypomyelinating POLR3-related leukodystrophy. Sanger sequencing confirmed the genetic origin of these POLR3A deleterious variants as autosomal recessive hereditary transmission. CONCLUSION Our report provides additional evidence for a phenotypic continuum of hypomyelinating POLR3-related leukodystrophy caused by bi-allelic POLR3A variants. Further genetic studies are required to understand underlying pleiotropic effects of different POLR3A variants.
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Affiliation(s)
- Ji Yoon Han
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yong Gon Cho
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea
| | - Joonhong Park
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea.
| | - Woori Jang
- Department of Laboratory Medicine, Inha University School of Medicine, Incheon, Korea.
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Wang Q, Daiß JL, Xu Y, Engel C. Snapshots of RNA polymerase III in action - A mini review. Gene 2022; 821:146282. [PMID: 35149153 DOI: 10.1016/j.gene.2022.146282] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/20/2022] [Accepted: 02/03/2022] [Indexed: 11/04/2022]
Abstract
RNA polymerase (Pol) III is responsible for the transcription of tRNAs, 5S rRNA, U6 snRNA, and other non-coding RNAs. Transcription factors such as TFIIIA, -B, -C, SNAPc, and Maf1 are required for promoter recognition, promoter opening, and Pol III activity regulation. Recent developments in cryo-electron microscopy and advanced purification approaches for endogenous multi-subunit complexes accelerated structural studies resulting in detailed structural insights which allowed an in-depth understanding of the molecular mechanisms underlying Pol III transcription. Here, we summarize structural data on Pol III and its regulating factors providing a three-dimensional framework to guide further analysis of RNA polymerase III.
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Affiliation(s)
- Qianmin Wang
- State Key Laboratory of Oncogenes and Related Genes, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Institute of Precision Medicine, Shanghai, China; Present address: Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany
| | - Youwei Xu
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany.
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Ando M, Higuchi Y, Yuan JH, Yoshimura A, Kitao R, Morimoto T, Taniguchi T, Takeuchi M, Takei J, Hiramatsu Y, Sakiyama Y, Hashiguchi A, Okamoto Y, Mitsui J, Ishiura H, Tsuji S, Takashima H. Novel de novo POLR3B mutations responsible for demyelinating Charcot-Marie-Tooth disease in Japan. Ann Clin Transl Neurol 2022; 9:747-755. [PMID: 35482004 PMCID: PMC9082381 DOI: 10.1002/acn3.51555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/10/2022] [Accepted: 03/24/2022] [Indexed: 12/24/2022] Open
Abstract
Background Biallelic POLR3B mutations cause a rare hypomyelinating leukodystrophy. De novo POLR3B heterozygous mutations were recently associated with afferent ataxia, spasticity, variable intellectual disability, and epilepsy, and predominantly demyelinating sensorimotor peripheral neuropathy. Methods We performed whole‐exome sequencing (WES) of DNA samples from 804 Charcot–Marie–Tooth (CMT) cases that could not be genetically diagnosed by DNA‐targeted resequencing microarray using next‐generation sequencers. Using WES data, we analyzed the POLR3B mutations and confirmed their clinical features. Results We identified de novo POLR3B heterozygous missense mutations in two patients. These patients presented with early‐onset demyelinating sensorimotor neuropathy without ataxia, spasticity, or cognitive impairment. Patient 1 showed mild cerebellar atrophy and spinal cord atrophy on magnetic resonance imaging and eventually died of respiratory failure in her 50s. We classified these mutations as pathogenic based on segregation studies, comparison with control database, and in silico analysis. Conclusion Our study is the third report on patients with demyelinating CMT harboring heterozygous POLR3B mutations and verifies the pathogenicity of POLR3B mutations in CMT. Although extremely rare in our large Japanese case series, POLR3B mutations should be added to the CMT‐related gene panel for comprehensive genetic screening, particularly for patients with early‐onset demyelinating CMT.
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Affiliation(s)
- Masahiro Ando
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun-Hui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Ruriko Kitao
- Department of Neurology, National Hospital Organization Hakone Hospital, Kanagawa, Japan
| | - Takehiko Morimoto
- Department of Pediatrics, Asahigawaso Minamiehime Rehabilitation Hospital, Ehime, Japan
| | - Takaki Taniguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Neurology, Imakiire General Hospital, Kagoshima, Japan
| | - Mika Takeuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun Takei
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yu Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yusuke Sakiyama
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Kagoshima, Japan
| | - Jun Mitsui
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Chiba, Japan
| | - Hiroyuki Ishiura
- Department of Neurology, Faculty of Medicine, The University of Tokyo, Chiba, Japan
| | - Shoji Tsuji
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Chiba, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Costei C, Barbarosie M, Bernard G, Brais B, La Piana R. Adult Hereditary White Matter Diseases With Psychiatric Presentation: Clinical Pointers and MRI Algorithm to Guide the Diagnostic Process. J Neuropsychiatry Clin Neurosci 2022; 33:180-193. [PMID: 33951919 DOI: 10.1176/appi.neuropsych.20110294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The investigators aimed to provide clinical and MRI guidelines for determining when genetic workup should be considered in order to exclude hereditary leukoencephalopathies in affected patients with a psychiatric presentation. METHODS A systematic literature review was conducted, and clinical cases are provided. Given the central role of MRI pattern recognition in the diagnosis of white matter disorders, the investigators adapted an MRI algorithm that guides the interpretation of MRI findings and thus directs further investigations, such as genetic testing. RESULTS Twelve genetic leukoencephalopathies that can present with psychiatric symptoms were identified. As examples of presentations that can occur in clinical practice, five clinical vignettes from patients assessed at a referral center for adult genetic leukoencephalopathies are provided. CONCLUSIONS Features such as drug-resistant symptoms, presence of long-standing somatic features, trigger events, consanguinity, and positive family history should orient the clinician toward diagnostic workup to exclude the presence of a genetic white matter disorder. The identification of MRI white matter abnormalities, especially when presenting a specific pattern of involvement, should prompt genetic testing for known forms of genetic leukoencephalopathies.
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Affiliation(s)
- Catalina Costei
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Michaela Barbarosie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
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Abstract
RNA polymerase III (Pol III) is a large multisubunit complex conserved in all eukaryotes that plays an essential role in producing a variety of short non-coding RNAs, such as tRNA, 5S rRNA and U6 snRNA transcripts. Pol III comprises of 17 subunits in both yeast and human with a 10-subunit core and seven peripheral subunits. Because of its size and complexity, Pol III has posed a formidable challenge to structural biologists. The first atomic cryogenic electron microscopy structure of yeast Pol III leading to the canonical view was reported in 2015. Within the last few years, the optimization of endogenous extract and purification procedure and the technical and methodological advances in cryogenic electron microscopy, together allow us to have a first look at the unprecedented details of human Pol III organization. Here, we look back on the structural studies of human Pol III and discuss them in the light of our current understanding of its role in eukaryotic transcription.
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Affiliation(s)
- Qianmin Wang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Ming Lei
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wu
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
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38
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Naseer MI, Abdulkareem AA, Pushparaj PN, Saharti S, Muthaffar OY. Next-Generation Sequencing Reveals Novel Homozygous Missense Variant c.934T > C in POLR1C Gene Causing Leukodystrophy and Hypomyelinating Disease. Front Pediatr 2022; 10:862722. [PMID: 35685919 PMCID: PMC9171136 DOI: 10.3389/fped.2022.862722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Leukodystrophies are a diverse group of genetically established disorders categorized by unusual white matter changes on brain imaging. Hypomyelinating leukodystrophies (HLDs) are a group of neurodevelopmental disorders that affect myelin sheath development in the brain. These disorders are categorized as developmental delay, spasticity, hypotonia, and intellectual disabilities. We describe a patient with developmental delay, cerebellar ataxia, spasticity, hypotonia, and intellectual disability from a healthy family member. Whole exome sequencing (WES) was performed to identify causative variants, which were further analyzed by bioinformatic analysis. WES was performed, and Sanger sequencing-based segregation analysis confirmed the presence of the homozygous missense variants of NM_203290.3 c.934T > C p.Ser312Pro of RNA polymerase I and III subunit C (POLR1C) gene in this patient and heterozygous variant in the unaffected carrier father and mother, supporting the pathogenicity and inheritance pattern of this variant. Furthermore, the variant identified by WES was validated in healthy controls (n = 100) using Sanger sequencing analysis. Finally, our study explained the important use of WES in disease diagnosis and provided further evidence that the variant in the POLR1C gene may play an important role in the development of hypomyelinating leukodystrophy in Saudi families.
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Affiliation(s)
- Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Angham Abdulrahman Abdulkareem
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Peter Natesan Pushparaj
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Pharmacology, Center for Transdisciplinary Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Samah Saharti
- Department of Pathology and Microbiology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Osama Y Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
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39
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Wang C, Wang S, Xie H, Yang S. Clinical and imaging characteristics of 4H syndrome: A case report. CNS Neurosci Ther 2021; 28:458-460. [PMID: 34953043 PMCID: PMC8841286 DOI: 10.1111/cns.13790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/02/2021] [Accepted: 12/12/2021] [Indexed: 11/29/2022] Open
Affiliation(s)
- Chao Wang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, NO.88 Jiefang Road, Hangzhou, China
| | - Shan Wang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, NO.88 Jiefang Road, Hangzhou, China
| | - Huanhuan Xie
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, NO.88 Jiefang Road, Hangzhou, China
| | - Siyu Yang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, NO.88 Jiefang Road, Hangzhou, China
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40
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Defective myelination in an RNA polymerase III mutant leukodystrophic mouse. Proc Natl Acad Sci U S A 2021; 118:2024378118. [PMID: 34583988 DOI: 10.1073/pnas.2024378118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2021] [Indexed: 01/06/2023] Open
Abstract
RNA polymerase (Pol) III synthesizes abundant short noncoding RNAs that have essential functions in protein synthesis, secretion, and other processes. Despite the ubiquitous functions of these RNAs, mutations in Pol III subunits cause Pol III-related leukodystrophy, an early-onset neurodegenerative disease. The basis of this neural sensitivity and the mechanisms of disease pathogenesis are unknown. Here we show that mice expressing pathogenic mutations in the largest Pol III subunit, Polr3a, specifically in Olig2-expressing cells, have impaired growth and developmental delay, deficits in cognitive, sensory, and fine sensorimotor function, and hypomyelination in multiple regions of the cerebrum and spinal cord. These phenotypes reflect a subset of clinical features seen in patients. In contrast, the gross motor defects and cerebellar hypomyelination that are common features of severely affected patients are absent in the mice, suggesting a relatively mild form of the disease in this conditional model. Our results show that disease pathogenesis in the mice involves defects that reduce both the number of mature myelinating oligodendrocytes and the ability of these cells to produce a myelin sheath of normal thickness. The findings suggest unique sensitivities of oligodendrogenesis and myelination to perturbations of Pol III transcription.
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41
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Yadav N, Saini J, Nagappa M. Novel Mutation in the POLR1C Gene Causing Hypomyelinating Leukodystrophy in an Adult. Neurol Clin Pract 2021; 11:e367-e369. [PMID: 34484918 DOI: 10.1212/cpj.0000000000001002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/01/2020] [Indexed: 11/15/2022]
Affiliation(s)
- Nishtha Yadav
- Department of Radiology (NY), Super Speciality Hospital, NSCB Medical College, Jabalpur; Department of Neuroimaging and Interventional Radiology (JS), and Department of Neurology (MN), National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Jitender Saini
- Department of Radiology (NY), Super Speciality Hospital, NSCB Medical College, Jabalpur; Department of Neuroimaging and Interventional Radiology (JS), and Department of Neurology (MN), National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Madhu Nagappa
- Department of Radiology (NY), Super Speciality Hospital, NSCB Medical College, Jabalpur; Department of Neuroimaging and Interventional Radiology (JS), and Department of Neurology (MN), National Institute of Mental Health and Neurosciences, Bengaluru, India
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42
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Barczykowski AL, Langan TJ, Vanderver A, Jalal K, Carter RL. Death rates in the U.S. due to Leukodystrophies with pediatric forms. Am J Med Genet A 2021; 185:2361-2373. [PMID: 33960638 PMCID: PMC11431180 DOI: 10.1002/ajmg.a.62248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 03/26/2021] [Accepted: 04/16/2021] [Indexed: 11/08/2022]
Abstract
To use national mortality and state death certificate records to estimate disease specific mortality rates among pediatric and adult populations for 23 leukodystrophies (LDs) with pediatric forms. Additionally, to calculate yearly prevalence and caseload of the most severe LD cases that will eventually result in pediatric death (i.e., pediatric fatality cases). Death certificate records describing cause of death were collected from states based on 10 ICD-10 codes associated with the 23 LDs. Deaths in the U.S. with these codes were distributed into categories based on proportions identified in state death certificate data. Mortality rates, prevalence, and caseload were calculated from resulting expected numbers, population sizes, and average lifetimes. An estimated 1.513 per 1,000,000 0-17 year old's died of these LDs at average age 5.2 years and 0.194 for those ≥18 at an average age of 42.3 years. Prevalence of pediatric fatality cases of these LDs declined from 1999 through 2007 and then remained constant at 6.2 per million children per year through 2012. Epidemiological information, currently lacking for rare diseases, is useful to newborn screening programs, research funding agencies, and care centers for LD patients. Methods used here are generally useful for studying rare diseases.
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Affiliation(s)
- Amy L. Barczykowski
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
| | - Thomas J. Langan
- Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
- Department of Neurology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Adeline Vanderver
- The Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- The Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kabir Jalal
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
| | - Randy L. Carter
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York
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43
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Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M. RNA Polymerase III Subunit Mutations in Genetic Diseases. Front Mol Biosci 2021; 8:696438. [PMID: 34395528 PMCID: PMC8362101 DOI: 10.3389/fmolb.2021.696438] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/21/2021] [Indexed: 12/24/2022] Open
Abstract
RNA polymerase (Pol) III transcribes small untranslated RNAs such as 5S ribosomal RNA, transfer RNAs, and U6 small nuclear RNA. Because of the functions of these RNAs, Pol III transcription is best known for its essential contribution to RNA maturation and translation. Surprisingly, it was discovered in the last decade that various inherited mutations in genes encoding nine distinct subunits of Pol III cause tissue-specific diseases rather than a general failure of all vital functions. Mutations in the POLR3A, POLR3C, POLR3E and POLR3F subunits are associated with susceptibility to varicella zoster virus-induced encephalitis and pneumonitis. In addition, an ever-increasing number of distinct mutations in the POLR3A, POLR3B, POLR1C and POLR3K subunits cause a spectrum of neurodegenerative diseases, which includes most notably hypomyelinating leukodystrophy. Furthermore, other rare diseases are also associated with mutations in genes encoding subunits of Pol III (POLR3H, POLR3GL) and the BRF1 component of the TFIIIB transcription initiation factor. Although the causal relationship between these mutations and disease development is widely accepted, the exact molecular mechanisms underlying disease pathogenesis remain enigmatic. Here, we review the current knowledge on the functional impact of specific mutations, possible Pol III-related disease-causing mechanisms, and animal models that may help to better understand the links between Pol III mutations and disease.
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Affiliation(s)
- Elisabeth Lata
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Karine Choquet
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Francis Sagliocco
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Martin Teichmann
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
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44
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Derksen A, Shih HY, Forget D, Darbelli L, Tran LT, Poitras C, Guerrero K, Tharun S, Alkuraya FS, Kurdi WI, Nguyen CTE, Laberge AM, Si Y, Gauthier MS, Bonkowsky JL, Coulombe B, Bernard G. Variants in LSM7 impair LSM complexes assembly, neurodevelopment in zebrafish and may be associated with an ultra-rare neurological disease. HGG ADVANCES 2021; 2:100034. [PMID: 35047835 PMCID: PMC8756503 DOI: 10.1016/j.xhgg.2021.100034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/28/2021] [Indexed: 11/15/2022] Open
Abstract
Leukodystrophies, genetic neurodevelopmental and/or neurodegenerative disorders of cerebral white matter, result from impaired myelin homeostasis and metabolism. Numerous genes have been implicated in these heterogeneous disorders; however, many individuals remain without a molecular diagnosis. Using whole-exome sequencing, biallelic variants in LSM7 were uncovered in two unrelated individuals, one with a leukodystrophy and the other who died in utero. LSM7 is part of the two principle LSM protein complexes in eukaryotes, namely LSM1-7 and LSM2-8. Here, we investigate the molecular and functional outcomes of these LSM7 biallelic variants in vitro and in vivo. Affinity purification-mass spectrometry of the LSM7 variants showed defects in the assembly of both LSM complexes. Lsm7 knockdown in zebrafish led to central nervous system defects, including impaired oligodendrocyte development and motor behavior. Our findings demonstrate that variants in LSM7 cause misassembly of the LSM complexes, impair neurodevelopment of the zebrafish, and may be implicated in human disease. The identification of more affected individuals is needed before the molecular mechanisms of mRNA decay and splicing regulation are added to the categories of biological dysfunctions implicated in leukodystrophies, neurodevelopmental and/or neurodegenerative diseases.
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Structure of human RNA polymerase III elongation complex. Cell Res 2021; 31:791-800. [PMID: 33674783 PMCID: PMC8249397 DOI: 10.1038/s41422-021-00472-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/06/2021] [Indexed: 01/31/2023] Open
Abstract
RNA polymerase III (Pol III) transcribes essential structured small RNAs, such as tRNAs, 5S rRNA and U6 snRNA. The transcriptional activity of Pol III is tightly controlled and its dysregulation is associated with human diseases, such as cancer. Human Pol III has two isoforms with difference only in one of its subunits RPC7 (α and β). Despite structural studies of yeast Pol III, structure of human Pol III remains unsolved. Here, we determined the structures of 17-subunit human Pol IIIα complex in the backtracked and post-translocation states, respectively. Human Pol III contains a generally conserved catalytic core, similar to that of yeast counterpart, and structurally unique RPC3-RPC6-RPC7 heterotrimer and RPC10. The N-ribbon of TFIIS-like RPC10 docks on the RPC4-RPC5 heterodimer and the C-ribbon inserts into the funnel of Pol III in the backtracked state but is more flexible in the post-translocation state. RPC7 threads through the heterotrimer and bridges the stalk and Pol III core module. The winged helix 1 domain of RPC6 and the N-terminal region of RPC7α stabilize each other and may prevent Maf1-mediated repression of Pol III activity. The C-terminal FeS cluster of RPC6 coordinates a network of interactions that mediate core-heterotrimer contacts and stabilize Pol III. Our structural analysis sheds new light on the molecular mechanism of human Pol IIIα-specific transcriptional regulation and provides explanations for upregulated Pol III activity in RPC7α-dominant cancer cells.
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von Jonquieres G, Rae CD, Housley GD. Emerging Concepts in Vector Development for Glial Gene Therapy: Implications for Leukodystrophies. Front Cell Neurosci 2021; 15:661857. [PMID: 34239416 PMCID: PMC8258421 DOI: 10.3389/fncel.2021.661857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/12/2021] [Indexed: 12/12/2022] Open
Abstract
Central Nervous System (CNS) homeostasis and function rely on intercellular synchronization of metabolic pathways. Developmental and neurochemical imbalances arising from mutations are frequently associated with devastating and often intractable neurological dysfunction. In the absence of pharmacological treatment options, but with knowledge of the genetic cause underlying the pathophysiology, gene therapy holds promise for disease control. Consideration of leukodystrophies provide a case in point; we review cell type – specific expression pattern of the disease – causing genes and reflect on genetic and cellular treatment approaches including ex vivo hematopoietic stem cell gene therapies and in vivo approaches using adeno-associated virus (AAV) vectors. We link recent advances in vectorology to glial targeting directed towards gene therapies for specific leukodystrophies and related developmental or neurometabolic disorders affecting the CNS white matter and frame strategies for therapy development in future.
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Affiliation(s)
- Georg von Jonquieres
- Translational Neuroscience Facility, Department of Physiology, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Caroline D Rae
- Neuroscience Research Australia, Randwick, NSW, Australia
| | - Gary D Housley
- Translational Neuroscience Facility, Department of Physiology, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia
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47
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Sweeney NM, Nahas SA, Chowdhury S, Batalov S, Clark M, Caylor S, Cakici J, Nigro JJ, Ding Y, Veeraraghavan N, Hobbs C, Dimmock D, Kingsmore SF. Rapid whole genome sequencing impacts care and resource utilization in infants with congenital heart disease. NPJ Genom Med 2021; 6:29. [PMID: 33888711 PMCID: PMC8062477 DOI: 10.1038/s41525-021-00192-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/19/2021] [Indexed: 11/09/2022] Open
Abstract
Congenital heart disease (CHD) is the most common congenital anomaly and a major cause of infant morbidity and mortality. While morbidity and mortality are highest in infants with underlying genetic conditions, molecular diagnoses are ascertained in only ~20% of cases using widely adopted genetic tests. Furthermore, cost of care for children and adults with CHD has increased dramatically. Rapid whole genome sequencing (rWGS) of newborns in intensive care units with suspected genetic diseases has been associated with increased rate of diagnosis and a net reduction in cost of care. In this study, we explored whether the clinical utility of rWGS extends to critically ill infants with structural CHD through a retrospective review of rWGS study data obtained from inpatient infants < 1 year with structural CHD at a regional children's hospital. rWGS diagnosed genetic disease in 46% of the enrolled infants. Moreover, genetic disease was identified five times more frequently with rWGS than microarray ± gene panel testing in 21 of these infants (rWGS diagnosed 43% versus 10% with microarray ± gene panels, p = 0.02). Molecular diagnoses ranged from syndromes affecting multiple organ systems to disorders limited to the cardiovascular system. The average daily hospital spending was lower in the time period post blood collection for rWGS compared to prior (p = 0.003) and further decreased after rWGS results (p = 0.000). The cost was not prohibitive to rWGS implementation in the care of this cohort of infants. rWGS provided timely actionable information that impacted care and there was evidence of decreased hospital spending around rWGS implementation.
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Affiliation(s)
- Nathaly M Sweeney
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA.
- Rady Children's Hospital, San Diego, CA, USA.
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
| | - Shareef A Nahas
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Shimul Chowdhury
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Sergey Batalov
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Michelle Clark
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Sara Caylor
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Julie Cakici
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA
| | - John J Nigro
- Rady Children's Hospital, San Diego, CA, USA
- Department of Surgery, University of California San Diego, La Jolla, CA, USA
| | - Yan Ding
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | | | - Charlotte Hobbs
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - David Dimmock
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
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48
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Combined Genome, Transcriptome and Metabolome Analysis in the Diagnosis of Childhood Cerebellar Ataxia. Int J Mol Sci 2021; 22:ijms22062990. [PMID: 33804237 PMCID: PMC8002209 DOI: 10.3390/ijms22062990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/11/2021] [Accepted: 03/13/2021] [Indexed: 12/30/2022] Open
Abstract
Ataxia in children is a common clinical sign of numerous neurological disorders consisting of impaired coordination of voluntary muscle movement. Its most common form, cerebellar ataxia, describes a heterogeneous array of neurologic conditions with uncountable causes broadly divided as acquired or genetic. Numerous genetic disorders are associated with chronic progressive ataxia, which complicates clinical management, particularly on the diagnostic stage. Advances in omics technologies enable improvements in clinical practice and research, so we proposed a multi-omics approach to aid in the genetic diagnosis and molecular elucidation of an undiagnosed infantile condition of chronic progressive cerebellar ataxia. Using whole-exome sequencing, RNA-seq, and untargeted metabolomics, we identified three clinically relevant mutations (rs141471029, rs191582628 and rs398124292) and an altered metabolic profile in our patient. Two POLR1C diagnostic variants already classified as pathogenic were found, and a diagnosis of hypomyelinating leukodystrophy was achieved. A mutation on the MMACHC gene, known to be associated with methylmalonic aciduria and homocystinuria cblC type, was also found. Additionally, preliminary metabolome analysis revealed alterations in our patient’s amino acid, fatty acid and carbohydrate metabolism. Our findings provided a definitive genetic diagnosis reinforcing the association between POLR1C mutations and hypomyelinating leukodystrophy and highlighted the relevance of multi-omics approaches to the disease.
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49
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Coulombe B, Derksen A, La Piana R, Brais B, Gauthier MS, Bernard G. POLR3-related leukodystrophy: How do mutations affecting RNA polymerase III subunits cause hypomyelination? Fac Rev 2021; 10:12. [PMID: 33659930 PMCID: PMC7894263 DOI: 10.12703/r/10-12] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Hypomyelinating leukodystrophies are a group of genetic disorders characterized by insufficient myelin deposition during development. A subset of hypomyelinating leukodystrophies, named RNA polymerase III (Pol III or POLR3)-related leukodystrophy or 4H (Hypomyelination, Hypodontia and Hypogonadotropic Hypogonadism) leukodystrophy, was found to be caused by biallelic variants in genes encoding subunits of the enzyme Pol III, including POLR3A, POLR3B, POLR3K, and POLR1C. Pol III is one of the three nuclear RNA polymerases that synthesizes small non-coding RNAs, such as tRNAs, 5S RNA, and others, that are involved in the regulation of essential cellular processes, including transcription, translation and RNA maturation. Affinity purification coupled with mass spectrometry (AP-MS) revealed that a number of mutations causing POLR3-related leukodystrophy impair normal assembly or biogenesis of Pol III, often causing a retention of the unassembled subunits in the cytoplasm. Even though these proteomic studies have helped to understand the molecular defects associated with leukodystrophy, how these mutations cause hypomyelination has yet to be defined. In this review we propose two main hypotheses to explain how mutations affecting Pol III subunits can cause hypomyelination.
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Affiliation(s)
- Benoit Coulombe
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Alexa Derksen
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Diagnostic Radiology, McGill University, Montréal, QC, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
| | - Marie-Soleil Gauthier
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
| | - Geneviève Bernard
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Department of Pediatrics, McGill University, Montréal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montréal, QC, Canada
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50
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Yan H, Ji H, Kubisiak T, Wu Y, Xiao J, Gu Q, Yang Y, Xie H, Ji T, Gao K, Li D, Xiong H, Shi Z, Li M, Zhang Y, Duan R, Bao X, Jiang Y, Burmeister M, Wang J. Genetic analysis of 20 patients with hypomyelinating leukodystrophy by trio-based whole-exome sequencing. J Hum Genet 2021; 66:761-768. [PMID: 33597727 PMCID: PMC8310791 DOI: 10.1038/s10038-020-00896-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/13/2020] [Accepted: 11/10/2020] [Indexed: 12/02/2022]
Abstract
Hypomyelinating leukodystrophies (HLDs) are a rare group of disorders characterized by myelin deficit of the brain-based on MRI. Here, we studied 20 patients with unexplained HLD to uncover their genetic etiology through whole-exome sequencing (WES). Trio-based WES was performed for 20 unresolved HLDs families after genetic tests for the PLP1 duplication and a panel of 115 known leukodystrophy-related genes. Variants in both known genes that related to HLDs and promising candidate genes were analyzed. Minigene splicing assay was conducted to confirm the effect of splice region variant. All 20 patients were diagnosed with HLDs clinically based on myelin deficit on MRI and impaired motor ability. Through WES, in 11 of 20 trios, 15 causative variants were detected in seven genes TUBB4A, POLR1C, POLR3A, SOX10, TMEM106B, DEGS1, and TMEM63A. The last three genes have just been discovered. Of 15 variants, six were novel. Using minigene splicing assay, splice variant POLR3A c.1770 + 5 G > C was proved to disrupt the normal splicing of intron 13 and led to a premature stop codon at position 618 (p.(P591Vfs*28)). Our analysis determined the molecular diagnosis of 11 HLDs patients. It emphasizes the heterogenicity of HLDs, the diagnostic power of trio-based WES for HLDs. Comprehensive analysis including a focus on candidate genes helps to discover novel disease-causing genes, determine the diagnosis for the first time, and improve the yield of WES. Moreover, novel mutations identified in TUBB4A, POLR3A, and POLR1C expand the mutation spectrum of these genes.
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Affiliation(s)
- Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.,Joint International Research Center of Translational and Clinical Research, Beijing, China
| | - Haoran Ji
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Thomas Kubisiak
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Han Xie
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Taoyun Ji
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Dongxiao Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhen Shi
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ming Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ruoyu Duan
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xinhua Bao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Joint International Research Center of Translational and Clinical Research, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Margit Burmeister
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA. .,Departments of Computational Medicine & Bioinformatics, Psychiatry and Human Genetics, University of Michigan, Ann Arbor, MI, USA.
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China. .,Joint International Research Center of Translational and Clinical Research, Beijing, China. .,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China.
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