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Ghasemi MR, Tehrani Fateh S, Moeinafshar A, Sadeghi H, Karimzadeh P, Mirfakhraie R, Rezaei M, Hashemi-Gorji F, Rezvani Kashani M, Fazeli Bavandpour F, Bagheri S, Moghimi P, Rostami M, Madannejad R, Roudgari H, Miryounesi M. Broadening the phenotype and genotype spectrum of novel mutations in pontocerebellar hypoplasia with a comprehensive molecular literature review. BMC Med Genomics 2024; 17:51. [PMID: 38347586 PMCID: PMC10863249 DOI: 10.1186/s12920-024-01810-0] [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: 04/26/2023] [Accepted: 01/16/2024] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Pontocerebellar hypoplasia is an umbrella term describing a heterogeneous group of prenatal neurodegenerative disorders mostly affecting the pons and cerebellum, with 17 types associated with 25 genes. However, some types of PCH lack sufficient information, which highlights the importance of investigating and introducing more cases to further elucidate the clinical, radiological, and biochemical features of these disorders. The aim of this study is to provide an in-depth review of PCH and to identify disease genes and their inheritance patterns in 12 distinct Iranian families with clinically confirmed PCH. METHODS Cases included in this study were selected based on their phenotypic and genetic information available at the Center for Comprehensive Genetic Services. Whole-exome sequencing (WES) was used to discover the underlying genetic etiology of participants' problems, and Sanger sequencing was utilized to confirm any suspected alterations. We also conducted a comprehensive molecular literature review to outline the genetic features of the various subtypes of PCH. RESULTS This study classified and described the underlying etiology of PCH into three categories based on the genes involved. Twelve patients also were included, eleven of whom were from consanguineous parents. Ten different variations in 8 genes were found, all of which related to different types of PCH. Six novel variations were reported, including SEPSECS, TSEN2, TSEN54, AMPD2, TOE1, and CLP1. Almost all patients presented with developmental delay, hypotonia, seizure, and microcephaly being common features. Strabismus and elevation in lactate levels in MR spectroscopy were novel phenotypes for the first time in PCH types 7 and 9. CONCLUSIONS This study merges previously documented phenotypes and genotypes with unique novel ones. Due to the diversity in PCH, we provided guidance for detecting and diagnosing these heterogeneous groups of disorders. Moreover, since certain critical conditions, such as spinal muscular atrophy, can be a differential diagnosis, providing cases with novel variations and clinical findings could further expand the genetic and clinical spectrum of these diseases and help in better diagnosis. Therefore, six novel genetic variants and novel clinical and paraclinical findings have been reported for the first time. Further studies are needed to elucidate the underlying mechanisms and potential therapeutic targets for PCH.
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Affiliation(s)
- Mohammad-Reza Ghasemi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, , Tehran, Iran
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Aysan Moeinafshar
- School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Hossein Sadeghi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, , Tehran, Iran
| | - Parvaneh Karimzadeh
- Pediatric Neurology Department, Mofid Children's Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Mirfakhraie
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, , Tehran, Iran
| | - Mitra Rezaei
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzad Hashemi-Gorji
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Morteza Rezvani Kashani
- Pediatric Neurology Department, Mofid Children's Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Saman Bagheri
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- School of Medicine, Islamic Azad University Tehran Medical Sciences, Tehran, Iran
| | - Parinaz Moghimi
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- School of Medicine, Islamic Azad University Tehran Medical Sciences, Tehran, Iran
| | - Masoumeh Rostami
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Madannejad
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hassan Roudgari
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Miryounesi
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, , Tehran, Iran.
- Center for Comprehensive Genetic Services, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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2
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Sekulovski S, Sušac L, Stelzl LS, Tampé R, Trowitzsch S. Structural basis of substrate recognition by human tRNA splicing endonuclease TSEN. Nat Struct Mol Biol 2023:10.1038/s41594-023-00992-y. [PMID: 37231152 DOI: 10.1038/s41594-023-00992-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 04/06/2023] [Indexed: 05/27/2023]
Abstract
Heterotetrameric human transfer RNA (tRNA) splicing endonuclease TSEN catalyzes intron excision from precursor tRNAs (pre-tRNAs), utilizing two composite active sites. Mutations in TSEN and its associated RNA kinase CLP1 are linked to the neurodegenerative disease pontocerebellar hypoplasia (PCH). Despite the essential function of TSEN, the three-dimensional assembly of TSEN-CLP1, the mechanism of substrate recognition, and the structural consequences of disease mutations are not understood in molecular detail. Here, we present single-particle cryogenic electron microscopy reconstructions of human TSEN with intron-containing pre-tRNAs. TSEN recognizes the body of pre-tRNAs and pre-positions the 3' splice site for cleavage by an intricate protein-RNA interaction network. TSEN subunits exhibit large unstructured regions flexibly tethering CLP1. Disease mutations localize far from the substrate-binding interface and destabilize TSEN. Our work delineates molecular principles of pre-tRNA recognition and cleavage by human TSEN and rationalizes mutations associated with PCH.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lukas Sušac
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lukas S Stelzl
- Faculty of Biology, Johannes Gutenberg University Mainz, Mainz, Germany
- KOMET 1, Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany.
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3
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Sekulovski S, Trowitzsch S. What connects splicing of transfer RNA precursor molecules with pontocerebellar hypoplasia? Bioessays 2023; 45:e2200130. [PMID: 36517085 DOI: 10.1002/bies.202200130] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 01/19/2023]
Abstract
Transfer RNAs (tRNAs) represent the most abundant class of RNA molecules in the cell and are key players during protein synthesis and cellular homeostasis. Aberrations in the extensive tRNA biogenesis pathways lead to severe neurological disorders in humans. Mutations in the tRNA splicing endonuclease (TSEN) and its associated RNA kinase cleavage factor polyribonucleotide kinase subunit 1 (CLP1) cause pontocerebellar hypoplasia (PCH), a heterogeneous group of neurodegenerative disorders, that manifest as underdevelopment of specific brain regions typically accompanied by microcephaly, profound motor impairments, and child mortality. Recently, we demonstrated that mutations leading to specific PCH subtypes destabilize TSEN in vitro and cause imbalances of immature to mature tRNA ratios in patient-derived cells. However, how tRNA processing defects translate to disease on a systems level has not been understood. Recent findings suggested that other cellular processes may be affected by mutations in TSEN/CLP1 and obscure the molecular mechanisms of PCH emergence. Here, we review PCH disease models linked to the TSEN/CLP1 machinery and discuss future directions to study neuropathogenesis.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
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4
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Olson AN, Song S, Dinman JD. Deep mutational analysis of elongation factor eEF2 residues implicated in human disease to identify functionally important contacts with the ribosome. J Biol Chem 2022; 299:102771. [PMID: 36470424 PMCID: PMC9830224 DOI: 10.1016/j.jbc.2022.102771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
An emerging body of research is revealing mutations in elongation factor eEF2 that are implicated in both inherited and de novo neurodevelopmental disorders. Previous structural analysis has revealed that most pathogenic amino acid substitutions map to the three main points of contact between eEF2 and critical large subunit rRNA elements of the ribosome, specifically to contacts with Helix 69, Helix 95, also known as the sarcin-ricin loop, and Helix 43 of the GTPase-associated center. In order to further investigate these eEF2-ribosome interactions, we identified a series of yeast eEF2 amino acid residues based on their proximity to these functionally important rRNA elements. Based on this analysis, we constructed mutant strains to sample the full range of amino acid sidechain biochemical properties, including acidic, basic, nonpolar, and deletion (alanine) residues. These were characterized with regard to their effects on cell growth, sensitivity to ribosome-targeting antibiotics, and translational fidelity. We also biophysically characterized one mutant from each of the three main points of contact with the ribosome using CD. Collectively, our findings from these studies identified functionally critical contacts between eEF2 and the ribosome. The library of eEF2 mutants generated in this study may serve as an important resource for biophysical studies of eEF2/ribosome interactions going forward.
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Affiliation(s)
- Alexandra N Olson
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Serena Song
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA.
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5
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Sekulovski S, Trowitzsch S. Transfer RNA processing - from a structural and disease perspective. Biol Chem 2022; 403:749-763. [PMID: 35728022 DOI: 10.1515/hsz-2021-0406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/24/2022] [Indexed: 01/05/2023]
Abstract
Transfer RNAs (tRNAs) are highly structured non-coding RNAs which play key roles in translation and cellular homeostasis. tRNAs are initially transcribed as precursor molecules and mature by tightly controlled, multistep processes that involve the removal of flanking and intervening sequences, over 100 base modifications, addition of non-templated nucleotides and aminoacylation. These molecular events are intertwined with the nucleocytoplasmic shuttling of tRNAs to make them available at translating ribosomes. Defects in tRNA processing are linked to the development of neurodegenerative disorders. Here, we summarize structural aspects of tRNA processing steps with a special emphasis on intron-containing tRNA splicing involving tRNA splicing endonuclease and ligase. Their role in neurological pathologies will be discussed. Identification of novel RNA substrates of the tRNA splicing machinery has uncovered functions unrelated to tRNA processing. Future structural and biochemical studies will unravel their mechanistic underpinnings and deepen our understanding of neurological diseases.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt/Main, Germany
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6
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Sekulovski S, Devant P, Panizza S, Gogakos T, Pitiriciu A, Heitmeier K, Ramsay EP, Barth M, Schmidt C, Tuschl T, Baas F, Weitzer S, Martinez J, Trowitzsch S. Assembly defects of human tRNA splicing endonuclease contribute to impaired pre-tRNA processing in pontocerebellar hypoplasia. Nat Commun 2021; 12:5610. [PMID: 34584079 PMCID: PMC8479045 DOI: 10.1038/s41467-021-25870-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/03/2021] [Indexed: 02/07/2023] Open
Abstract
Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1. Splice site recognition involves the mature domain and the anticodon-intron base pair of pre-tRNAs. The 2.1-Å resolution X-ray crystal structure of a TSEN15–34 heterodimer and differential scanning fluorimetry analyses show that PCH mutations cause thermal destabilization. While endonuclease activity in recombinant mutant TSEN is unaltered, we observe assembly defects and reduced pre-tRNA cleavage activity resulting in an imbalanced pre-tRNA pool in PCH patient-derived fibroblasts. Our work defines the molecular principles of intron excision in humans and provides evidence that modulation of TSEN stability may contribute to PCH phenotypes. Mutations within subunits of the tRNA splicing endonuclease complex (TSEN) are associated with pontocerebellar hypoplasia (PCH). Here the authors show that tRNA intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers, and provide evidence that modulation of TSEN stability may contribute to PCH phenotypes.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Pascal Devant
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.,Ph.D. Program in Virology, Harvard Medical School, Boston, MA, USA.,Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Silvia Panizza
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Tasos Gogakos
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Anda Pitiriciu
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Katharina Heitmeier
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | | | - Marie Barth
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carla Schmidt
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Thomas Tuschl
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Frank Baas
- Department of Clinical Genetics, Leiden University, Leiden, Netherlands
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.
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7
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Wang Y, Zhang D, Hu X. A Three-Gene Peripheral Blood Potential Diagnosis Signature for Acute Rejection in Renal Transplantation. Front Mol Biosci 2021; 8:661661. [PMID: 34017855 PMCID: PMC8129004 DOI: 10.3389/fmolb.2021.661661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/21/2021] [Indexed: 12/31/2022] Open
Abstract
Background: Acute rejection (AR) remains a major issue that negatively impacts long-term allograft survival in renal transplantation. The current study aims to apply machine learning methods to develop a non-invasive diagnostic test for AR based on gene signature in peripheral blood. Methods: We collected blood gene expression profiles of 251 renal transplant patients with biopsy-proven renal status from three independent cohorts in the Gene Expression Omnibus database. After differential expression analysis and machine learning algorithms, selected biomarkers were applied to the least absolute shrinkage and selection operator (LASSO) logistic regression to construct a diagnostic model in the training cohort. The diagnostic ability of the model was further tested in validation cohorts. Gene set enrichment analysis and immune cell assessment were also conducted for further investigation. Results: A novel diagnostic model based on three genes (TSEN15, CAPRIN1 and PRR34-AS1) was constructed in the training cohort (AUC = 0.968) and successfully verified in the validation cohort (AUC = 0.925) with high accuracy. Moreover, the diagnostic model also showed a promising value in discriminating T cell-mediated rejection (TCMR) (AUC = 0.786). Functional enrichment analysis and immune cell evaluation demonstrated that the AR model was significantly correlated with adaptive immunity, especially T cell subsets and dendritic cells. Conclusion: We identified and validated a novel three-gene diagnostic model with high accuracy for AR in renal transplant patients, and the model also performed well in distinguishing TCMR. The current study provided a promising tool to be used as a precise and cost-effective non-invasive test in clinical practice.
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Affiliation(s)
- Yicun Wang
- Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.,Institute of Urology, Capital Medical University, Beijing, China
| | - Di Zhang
- Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.,Institute of Urology, Capital Medical University, Beijing, China
| | - Xiaopeng Hu
- Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China.,Institute of Urology, Capital Medical University, Beijing, China
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8
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Müller JS, Burns DT, Griffin H, Wells GR, Zendah RA, Munro B, Schneider C, Horvath R. RNA exosome mutations in pontocerebellar hypoplasia alter ribosome biogenesis and p53 levels. Life Sci Alliance 2020; 3:3/8/e202000678. [PMID: 32527837 PMCID: PMC7295610 DOI: 10.26508/lsa.202000678] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/01/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
The RNA exosome is a ubiquitously expressed complex of nine core proteins (EXOSC1-9) and associated nucleases responsible for RNA processing and degradation. Mutations in EXOSC3, EXOSC8, EXOSC9, and the exosome cofactor RBM7 cause pontocerebellar hypoplasia and motor neuronopathy. We investigated the consequences of exosome mutations on RNA metabolism and cellular survival in zebrafish and human cell models. We observed that levels of mRNAs encoding p53 and ribosome biogenesis factors are increased in zebrafish lines with homozygous mutations of exosc8 or exosc9, respectively. Consistent with higher p53 levels, mutant zebrafish have a reduced head size, smaller brain, and cerebellum caused by an increased number of apoptotic cells during development. Down-regulation of EXOSC8 and EXOSC9 in human cells leads to p53 protein stabilisation and G2/M cell cycle arrest. Increased p53 transcript levels were also observed in muscle samples from patients with EXOSC9 mutations. Our work provides explanation for the pathogenesis of exosome-related disorders and highlights the link between exosome function, ribosome biogenesis, and p53-dependent signalling. We suggest that exosome-related disorders could be classified as ribosomopathies.
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Affiliation(s)
- Juliane S Müller
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - David T Burns
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Griffin
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Graeme R Wells
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Romance A Zendah
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Benjamin Munro
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - Claudia Schneider
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK .,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
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9
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10
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Díaz-Casado E, Gómez-Nieto R, de Pereda JM, Muñoz LJ, Jara-Acevedo M, López DE. Analysis of gene variants in the GASH/Sal model of epilepsy. PLoS One 2020; 15:e0229953. [PMID: 32168507 PMCID: PMC7069730 DOI: 10.1371/journal.pone.0229953] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/17/2020] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is a complex neurological disorder characterized by sudden and recurrent seizures, which are caused by various factors, including genetic abnormalities. Several animal models of epilepsy mimic the different symptoms of this disorder. In particular, the genetic audiogenic seizure hamster from Salamanca (GASH/Sal) animals exhibit sound-induced seizures similar to the generalized tonic seizures observed in epileptic patients. However, the genetic alterations underlying the audiogenic seizure susceptibility of the GASH/Sal model remain unknown. In addition, gene variations in the GASH/Sal might have a close resemblance with those described in humans with epilepsy, which is a prerequisite for any new preclinical studies that target genetic abnormalities. Here, we performed whole exome sequencing (WES) in GASH/Sal animals and their corresponding controls to identify and characterize the mutational landscape of the GASH/Sal strain. After filtering the results, moderate- and high-impact variants were validated by Sanger sequencing, assessing the possible impact of the mutations by “in silico” reconstruction of the encoded proteins and analyzing their corresponding biological pathways. Lastly, we quantified gene expression levels by RT-qPCR. In the GASH/Sal model, WES showed the presence of 342 variations, in which 21 were classified as high-impact mutations. After a full bioinformatics analysis to highlight the high quality and reliable variants, the presence of 3 high-impact and 15 moderate-impact variants were identified. Gene expression analysis of the high-impact variants of Asb14 (ankyrin repeat and SOCS Box Containing 14), Msh3 (MutS Homolog 3) and Arhgef38 (Rho Guanine Nucleotide Exchange Factor 38) genes showed a higher expression in the GASH/Sal than in control hamsters. In silico analysis of the functional consequences indicated that those mutations in the three encoded proteins would have severe functional alterations. By functional analysis of the variants, we detected 44 significantly enriched pathways, including the glutamatergic synapse pathway. The data show three high-impact mutations with a major impact on the function of the proteins encoded by these genes, although no mutation in these three genes has been associated with some type of epilepsy until now. Furthermore, GASH/Sal animals also showed gene variants associated with different types of epilepsy that has been extensively documented, as well as mutations in other genes that encode proteins with functions related to neuronal excitability, which could be implied in the phenotype of the GASH/Sal. Our findings provide valuable genetic and biological pathway data associated to the genetic burden of the audiogenic seizure susceptibility and reinforce the need to validate the role of each key mutation in the phenotype of the GASH/Sal model.
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Affiliation(s)
- Elena Díaz-Casado
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
- Salamanca Institute for Biomedical Research, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
- Salamanca Institute for Biomedical Research, Salamanca, Spain
- Department of Cell Biology and Pathology, School Medicine, University of Salamanca, Salamanca, Spain
| | - José M. de Pereda
- Institute of Molecular and Cellular Biology of Cancer, CSIC.—University of Salamanca, Salamanca, Spain
| | - Luis J. Muñoz
- Animal facilities, University of Salamanca, Salamanca, Spain
| | | | - Dolores E. López
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
- Salamanca Institute for Biomedical Research, Salamanca, Spain
- Department of Cell Biology and Pathology, School Medicine, University of Salamanca, Salamanca, Spain
- * E-mail:
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11
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Tahmasebi S, Khoutorsky A, Mathews MB, Sonenberg N. Translation deregulation in human disease. Nat Rev Mol Cell Biol 2019; 19:791-807. [PMID: 30038383 DOI: 10.1038/s41580-018-0034-x] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Advances in sequencing and high-throughput techniques have provided an unprecedented opportunity to interrogate human diseases on a genome-wide scale. The list of disease-causing mutations is expanding rapidly, and mutations affecting mRNA translation are no exception. Translation (protein synthesis) is one of the most complex processes in the cell. The orchestrated action of ribosomes, tRNAs and numerous translation factors decodes the information contained in mRNA into a polypeptide chain. The intricate nature of this process renders it susceptible to deregulation at multiple levels. In this Review, we summarize current evidence of translation deregulation in human diseases other than cancer. We discuss translation-related diseases on the basis of the molecular aberration that underpins their pathogenesis (including tRNA dysfunction, ribosomopathies, deregulation of the integrated stress response and deregulation of the mTOR pathway) and describe how deregulation of translation generates the phenotypic variability observed in these disorders.
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Affiliation(s)
- Soroush Tahmasebi
- Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada. .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada. .,Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA.
| | - Arkady Khoutorsky
- Department of Anesthesia and Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada
| | - Michael B Mathews
- Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Nahum Sonenberg
- Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada. .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
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12
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Hirata A. Recent Insights Into the Structure, Function, and Evolution of the RNA-Splicing Endonucleases. Front Genet 2019; 10:103. [PMID: 30809252 PMCID: PMC6379350 DOI: 10.3389/fgene.2019.00103] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/30/2019] [Indexed: 11/13/2022] Open
Abstract
RNA-splicing endonuclease (EndA) cleaves out introns from archaeal and eukaryotic precursor (pre)-tRNA and is essential for tRNA maturation. In archaeal EndA, the molecular mechanisms underlying complex assembly, substrate recognition, and catalysis have been well understood. Recently, certain studies have reported novel findings including the identification of new subunit types in archaeal EndA structures, providing insights into the mechanism underlying broad substrate specificity. Further, metagenomics analyses have enabled the acquisition of numerous DNA sequences of EndAs and intron-containing pre-tRNAs from various species, providing information regarding the co-evolution of substrate specificity of archaeal EndAs and tRNA genetic diversity, and the evolutionary pathway of archaeal and eukaryotic EndAs. Although the complex structure of the heterothermic form of eukaryotic EndAs is unknown, previous reports regarding their functions indicated that mutations in human EndA cause neurological disorders including pontocerebellar hypoplasia and progressive microcephaly, and yeast EndA significantly cleaves mitochondria-localized mRNA encoding cytochrome b mRNA processing 1 (Cpb1) for mRNA maturation. This mini-review summarizes the aforementioned results, discusses their implications, and offers my personal opinion regarding future directions for the analysis of the structure and function of EndAs.
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Affiliation(s)
- Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
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Accogli A, Guerrero K, D'Agostino MD, Tran L, Cieuta-Walti C, Thiffault I, Chénier S, Schwartzentruber J, Majewski J, Bernard G. Biallelic Loss-of-Function Variants in AIMP1 Cause a Rare Neurodegenerative Disease. J Child Neurol 2019; 34:74-80. [PMID: 30486714 DOI: 10.1177/0883073818811223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
AIMP1/p43, is a noncatalytic component of the mammalian multi-tRNA synthetase complex that catalyzes the ligation of amino acids to their cognate tRNAs. AIMP1 is largely expressed in the central nervous system, where it is part of the regulatory machine of the neurofilament assembly, playing a crucial role in neuronal development and function. To date, nonsense mutations in AIMP1 have been associated with a primary neurodegenerative disorder consisting of cerebral atrophy, hypomyelination, microcephaly and epilepsy, whereas missense mutations have recently been linked to intellectual disability without neurodegeneration. Here, we report the first French-Canadian patient with a novel frameshift AIMP1 homozygous mutation (c.191_192delAA, p.Gln64Argfs*25), resulting in a severe neurodegenerative phenotype. We review and discuss the phenotypic spectrum associated with AIMP1 pathogenic variants.
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Affiliation(s)
- Andrea Accogli
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,2 UOC Neurochirurgia, Istituto Giannina Gaslini, Genova, Italy.,3 Università degli Studi di Genova, Genoa, Italy
| | - Kether Guerrero
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
| | - Maria Daniela D'Agostino
- 4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,6 Department of Human Genetics, McGill University, Montreal, Canada
| | - Luan Tran
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
| | - Cécile Cieuta-Walti
- 7 Service de Neuropédiatre, Université de Sherbrooke, Quebec, Canada.,8 Institut Lejeune, Paris, France
| | - Isabelle Thiffault
- 9 Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, MO, USA.,10 University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Sébastien Chénier
- 11 Department of Pediatrics, Division of Medical Genetics, Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | | | - Jacek Majewski
- 6 Department of Human Genetics, McGill University, Montreal, Canada
| | | | - Geneviève Bernard
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
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