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Kofler L, Grundmann L, Gerhalter M, Prattes M, Merl-Pham J, Zisser G, Grishkovskaya I, Hodirnau VV, Vareka M, Breinbauer R, Hauck SM, Haselbach D, Bergler H. The novel ribosome biogenesis inhibitor usnic acid blocks nucleolar pre-60S maturation. Nat Commun 2024; 15:7511. [PMID: 39209816 PMCID: PMC11362459 DOI: 10.1038/s41467-024-51754-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 08/11/2024] [Indexed: 09/04/2024] Open
Abstract
The formation of new ribosomes is tightly coordinated with cell growth and proliferation. In eukaryotes, the correct assembly of all ribosomal proteins and RNAs follows an intricate scheme of maturation and rearrangement steps across three cellular compartments: the nucleolus, nucleoplasm, and cytoplasm. We demonstrate that usnic acid, a lichen secondary metabolite, inhibits the maturation of the large ribosomal subunit in yeast. We combine biochemical characterization of pre-ribosomal particles with a quantitative single-particle cryo-EM approach to monitor changes in nucleolar particle populations upon drug treatment. Usnic acid rapidly blocks the transition from nucleolar state B to C of Nsa1-associated pre-ribosomes, depleting key maturation factors such as Dbp10 and hindering pre-rRNA processing. This primary nucleolar block rapidly rebounds on earlier stages of the pathway which highlights the regulatory linkages between different steps. In summary, we provide an in-depth characterization of the effect of usnic acid on ribosome biogenesis, which may have implications for its reported anti-cancer activities.
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Affiliation(s)
- Lisa Kofler
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Lorenz Grundmann
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | | | - Michael Prattes
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Juliane Merl-Pham
- Core Facility Metabolomics and Proteomics (CF-MPC), Helmholtz Center Munich, German Center for Environmental Health GmbH, D-80939, Munich, Germany
| | - Gertrude Zisser
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria
| | - Irina Grishkovskaya
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria
| | | | - Martin Vareka
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz, 8010, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz, 8010, Austria
| | - Stefanie M Hauck
- Core Facility Metabolomics and Proteomics (CF-MPC), Helmholtz Center Munich, German Center for Environmental Health GmbH, D-80939, Munich, Germany
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria.
| | - Helmut Bergler
- Institute of Molecular Biosciences, University of Graz, Graz, 8010, Austria.
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2
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Moir RD, Merheb E, Chitu V, Richard Stanley E, Willis IM. Molecular basis of neurodegeneration in a mouse model of Polr3-related disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.12.571310. [PMID: 38168294 PMCID: PMC10760057 DOI: 10.1101/2023.12.12.571310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Pathogenic variants in subunits of RNA polymerase (Pol) III cause a spectrum of Polr3-related neurodegenerative diseases including 4H leukodystrophy. Disease onset occurs from infancy to early adulthood and is associated with a variable range and severity of neurological and non-neurological features. The molecular basis of Polr3-related disease pathogenesis is unknown. We developed a postnatal whole-body mouse model expressing pathogenic Polr3a mutations to examine the molecular mechanisms by which reduced Pol III transcription results primarily in central nervous system phenotypes. Polr3a mutant mice exhibit behavioral deficits, cerebral pathology and exocrine pancreatic atrophy. Transcriptome and immunohistochemistry analyses of cerebra during disease progression show a reduction in most Pol III transcripts, induction of innate immune and integrated stress responses and cell type-specific gene expression changes reflecting neuron and oligodendrocyte loss and microglial activation. Earlier in the disease when integrated stress and innate immune responses are minimally induced, mature tRNA sequencing revealed a global reduction in tRNA levels and an altered tRNA profile but no changes in other Pol III transcripts. Thus, changes in the size and/or composition of the tRNA pool have a causal role in disease initiation. Our findings reveal different tissue- and brain region-specific sensitivities to a defect in Pol III transcription.
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Affiliation(s)
- Robyn D. Moir
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Emilio Merheb
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - E. Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
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3
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Wang Y, Vandewalle N, De Veirman K, Vanderkerken K, Menu E, De Bruyne E. Targeting mTOR signaling pathways in multiple myeloma: biology and implication for therapy. Cell Commun Signal 2024; 22:320. [PMID: 38862983 PMCID: PMC11165851 DOI: 10.1186/s12964-024-01699-3] [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: 02/13/2024] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
Multiple Myeloma (MM), a cancer of terminally differentiated plasma cells, is the second most prevalent hematological malignancy and is incurable due to the inevitable development of drug resistance. Intense protein synthesis is a distinctive trait of MM cells, supporting the massive production of clonal immunoglobulins or free light chains. The mammalian target of rapamycin (mTOR) kinase is appreciated as a master regulator of vital cellular processes, including regulation of metabolism and protein synthesis, and can be found in two multiprotein complexes, mTORC1 and mTORC2. Dysregulation of these complexes is implicated in several types of cancer, including MM. Since mTOR has been shown to be aberrantly activated in a large portion of MM patients and to play a role in stimulating MM cell survival and resistance to several existing therapies, understanding the regulation and functions of the mTOR complexes is vital for the development of more effective therapeutic strategies. This review provides a general overview of the mTOR pathway, discussing key discoveries and recent insights related to the structure and regulation of mTOR complexes. Additionally, we highlight findings on the mechanisms by which mTOR is involved in protein synthesis and delve into mTOR-mediated processes occurring in MM. Finally, we summarize the progress and current challenges of drugs targeting mTOR complexes in MM.
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Affiliation(s)
- Yanmeng Wang
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Niels Vandewalle
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Kim De Veirman
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Universitair Ziekenhuis Brussel (UZ Brussel), Jette, Belgium
| | - Karin Vanderkerken
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Eline Menu
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
| | - Elke De Bruyne
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
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4
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Hwang SP, Denicourt C. The impact of ribosome biogenesis in cancer: from proliferation to metastasis. NAR Cancer 2024; 6:zcae017. [PMID: 38633862 PMCID: PMC11023387 DOI: 10.1093/narcan/zcae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/23/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
The dysregulation of ribosome biogenesis is a hallmark of cancer, facilitating the adaptation to altered translational demands essential for various aspects of tumor progression. This review explores the intricate interplay between ribosome biogenesis and cancer development, highlighting dynamic regulation orchestrated by key oncogenic signaling pathways. Recent studies reveal the multifaceted roles of ribosomes, extending beyond protein factories to include regulatory functions in mRNA translation. Dysregulated ribosome biogenesis not only hampers precise control of global protein production and proliferation but also influences processes such as the maintenance of stem cell-like properties and epithelial-mesenchymal transition, contributing to cancer progression. Interference with ribosome biogenesis, notably through RNA Pol I inhibition, elicits a stress response marked by nucleolar integrity loss, and subsequent G1-cell cycle arrest or cell death. These findings suggest that cancer cells may rely on heightened RNA Pol I transcription, rendering ribosomal RNA synthesis a potential therapeutic vulnerability. The review further explores targeting ribosome biogenesis vulnerabilities as a promising strategy to disrupt global ribosome production, presenting therapeutic opportunities for cancer treatment.
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Affiliation(s)
- Sseu-Pei Hwang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Catherine Denicourt
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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5
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Borland G, Wilkie SE, Thomson J, Wang Z, Tullet JMA, Alic N, Selman C. Polr3b heterozygosity in mice induces both beneficial and deleterious effects on health during ageing with no effect on lifespan. Aging Cell 2024; 23:e14141. [PMID: 38465473 PMCID: PMC11113255 DOI: 10.1111/acel.14141] [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: 10/19/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/12/2024] Open
Abstract
The genetic pathways that modulate ageing in multicellular organisms are typically highly conserved across wide evolutionary distances. Recently RNA polymerase III (Pol III) was shown to promote ageing in yeast, C. elegans and D. melanogaster. In this study we investigated the role of Pol III in mammalian ageing using C57BL/6N mice heterozygous for Pol III (Polr3b+/-). We identified sexually dimorphic, organ-specific beneficial as well as detrimental effects of the Polr3b+/- mutation on health. Female Polr3b+/- mice displayed improved bone health during ageing, but their ability to maintain an effective gut barrier function was compromised and they were susceptible to idiopathic dermatitis (ID). In contrast, male Polr3b+/- mice were lighter than wild-type (WT) males and had a significantly improved gut barrier function in old age. Several metabolic parameters were affected by both age and sex, but no genotype differences were detected. Neither male nor female Polr3b+/- mice were long-lived compared to WT controls. Overall, we find no evidence that a reduced Pol III activity extends mouse lifespan but we do find some potential organ- and sex-specific benefits for old-age health.
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Affiliation(s)
- Gillian Borland
- School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
- Present address:
School of Molecular BiosciencesUniversity of GlasgowGlasgowUK
| | - Stephen E. Wilkie
- School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
- Present address:
Division of Molecular Metabolism, Department of Medical Biochemistry and BiophysicsKarolinska InstitutetSolnaSweden
| | - Jackie Thomson
- School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
| | - Zhe Wang
- School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
| | | | - Nazif Alic
- Department of Genetics Evolution and Environment, Institute of Healthy AgeingUniversity College LondonLondonUK
| | - Colin Selman
- School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
- Present address:
School of Molecular BiosciencesUniversity of GlasgowGlasgowUK
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6
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Iwata-Otsubo A, Skraban CM, Yoshimura A, Sakata T, Alves CAP, Fiordaliso SK, Kuroda Y, Vengoechea J, Grochowsky A, Ernste P, Lulis L, Nesbitt A, Tayoun AA, Gray C, Towne MC, Radtke K, Normand EA, Rhodes L, Seiler C, Shirahige K, Izumi K. Biallelic variants in GTF3C5, a regulator of RNA polymerase III-mediated transcription, cause a multisystem developmental disorder. Hum Genet 2024; 143:437-453. [PMID: 38520561 DOI: 10.1007/s00439-024-02656-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/13/2024] [Indexed: 03/25/2024]
Abstract
General transcription factor IIIC subunit 5 (GTF3C5) encodes transcription factor IIIC63 (TFIIIC63). It binds to DNA to recruit another transcription factor, TFIIIB, and RNA polymerase III (Pol III) to mediate the transcription of small noncoding RNAs, such as tRNAs. Here, we report four individuals from three families presenting with a multisystem developmental disorder phenotype with biallelic variants in GTF3C5. The overlapping features include growth retardation, developmental delay, intellectual disability, dental anomalies, cerebellar malformations, delayed bone age, skeletal anomalies, and facial dysmorphism. Using lymphoblastoid cell lines (LCLs) from two affected individuals, we observed a reduction in TFIIIC63 protein levels compared to control LCLs. Genome binding of TFIIIC63 protein is also reduced in LCL from one of the affected individuals. Additionally, approximately 40% of Pol III binding regions exhibited reduction in the level of Pol III occupancy in the mutant genome relative to the control, while approximately 54% of target regions showed comparable levels of Pol III occupancy between the two, indicating partial impairment of Pol III occupancy in the mutant genome. Yeasts with subject-specific variants showed temperature sensitivity and impaired growth, supporting the notion that the identified variants have deleterious effects. gtf3c5 mutant zebrafish showed developmental defects, including a smaller body, head, and eyes. Taken together, our data show that GTF3C5 plays an important role in embryonic development, and that biallelic variants in this gene cause a multisystem developmental disorder. Our study adds GTF3C5-related disorder to the growing list of genetic disorders associated with Pol III transcription machinery.
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Affiliation(s)
- Aiko Iwata-Otsubo
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pathology, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI, 48109, USA.
| | - Cara M Skraban
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Pediatrics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Atsunori Yoshimura
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Toyonori Sakata
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Cesar Augusto P Alves
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Sarah K Fiordaliso
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Yukiko Kuroda
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Jaime Vengoechea
- Department of Human Genetics, Emory University, Atlanta, GA, 30322, USA
| | - Angela Grochowsky
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Paige Ernste
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Invitae, San Francisco, CA, 94103, USA
| | - Lauren Lulis
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Addie Nesbitt
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Veritas Genetics, Danvers, MA, 01923, USA
| | - Ahmad Abou Tayoun
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Genomics Center of Excellence, Al Jalila Children's Specialty Hospital, Dubai Health, Center for Genomic Discovery, Mohammed Bin Rashid University, Dubai Health, UAE
| | - Christopher Gray
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | | | | | | | | | - Christoph Seiler
- Zebrafish Core, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Katsuhiko Shirahige
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Kosuke Izumi
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pediatrics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Laboratory of Rare Disease Research, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan.
- Division of Genetics and Metabolism, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-8573, USA.
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7
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Ni C, Yu L, Vona B, Park D, Wei Y, Schmitz DA, Wei Y, Ding Y, Sakurai M, Ballard E, Liu Y, Kumar A, Xing C, Kim HG, Ekmekci C, Karimiani EG, Imannezhad S, Eghbal F, Badv RS, Schwaibold EMC, Dehghani M, Mehrjardi MYV, Metanat Z, Eslamiyeh H, Khouj E, Alhajj SMN, Chedrawi A, Alves CAPF, Houlden H, Kruer M, Alkuraya FS, Cenik C, Maroofian R, Wu J, Buszczak M. An inappropriate decline in ribosome levels drives a diverse set of neurodevelopmental disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574708. [PMID: 38260472 PMCID: PMC10802443 DOI: 10.1101/2024.01.09.574708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Many neurodevelopmental defects are linked to perturbations in genes involved in housekeeping functions, such as those encoding ribosome biogenesis factors. However, how reductions in ribosome biogenesis can result in tissue and developmental specific defects remains a mystery. Here we describe new allelic variants in the ribosome biogenesis factor AIRIM primarily associated with neurodevelopmental disorders. Using human cerebral organoids in combination with proteomic analysis, single-cell transcriptome analysis across multiple developmental stages, and single organoid translatome analysis, we identify a previously unappreciated mechanism linking changes in ribosome levels and the timing of cell fate specification during early brain development. We find ribosome levels decrease during neuroepithelial differentiation, making differentiating cells particularly vulnerable to perturbations in ribosome biogenesis during this time. Reduced ribosome availability more profoundly impacts the translation of specific transcripts, disrupting both survival and cell fate commitment of transitioning neuroepithelia. Enhancing mTOR activity by both genetic and pharmacologic approaches ameliorates the growth and developmental defects associated with intellectual disability linked variants, identifying potential treatment options for specific brain ribosomopathies. This work reveals the cellular and molecular origins of protein synthesis defect-related disorders of human brain development. Highlights AIRIM variants reduce ribosome levels specifically in neural progenitor cells. Inappropriately low ribosome levels cause a transient delay in radial glia fate commitment.Reduced ribosome levels impair translation of a selected subset of mRNAs.Genetic and pharmacologic activation of mTORC1 suppresses AIRIM-linked phenotypes.
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8
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Brooks WH. Polyamine Dysregulation and Nucleolar Disruption in Alzheimer's Disease. J Alzheimers Dis 2024; 98:837-857. [PMID: 38489184 DOI: 10.3233/jad-231184] [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] [Indexed: 03/17/2024]
Abstract
A hypothesis of Alzheimer's disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli. Polyamines are essential in nucleolar functions, such as RNA folding and ribonucleoprotein assembly. Changes in the nucleolar pool of anionic RNA and cationic polyamines acting as counterions can cause significant nucleolar dynamics. Polyamine synthesis reduces S-adenosylmethionine which, at low levels, triggers tau phosphorylation. Also, polyamine recycling reduces acetyl-CoA needed for acetylcholine, which is low in Alzheimer's disease. Extraordinary nucleolar expansion and/or contraction can disrupt epigenetic control in peri-nucleolar chromatin, such as chromosome 14 with the presenilin-1 gene; chromosome 21 with the amyloid precursor protein gene; chromosome 17 with the tau gene; chromosome 19 with the APOE4 gene; and the inactive X chromosome (Xi; aka "nucleolar satellite") with normally silent spermine synthase (polyamine synthesis) and spermidine/spermine-N1-acetyltransferase (polyamine recycling) alleles. Chromosomes 17, 19 and the Xi have high concentrations of Alu elements which can be transcribed by RNA polymerase III if positioned nucleosomes are displaced from the Alu elements. A sudden flood of Alu RNA transcripts can competitively bind nucleolin which is usually bound to Alu sequences in structural RNAs that stabilize the nucleolar heterochromatic shell. This Alu competition leads to loss of nucleolar integrity with leaking of nucleolar polyamines that cause aggregation of phosphorylated tau. The hypothesis was developed with key word searches (e.g., PubMed) using relevant terms (e.g., Alzheimer's, lupus, nucleolin) based on a systems biology approach and exploring autoimmune disease tautology, gaining synergistic insights from other diseases.
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9
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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: 3] [Impact Index Per Article: 3.0] [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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10
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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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11
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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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12
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Zhou S, Van Bortle K. The Pol III transcriptome: Basic features, recurrent patterns, and emerging roles in cancer. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1782. [PMID: 36754845 PMCID: PMC10498592 DOI: 10.1002/wrna.1782] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 02/10/2023]
Abstract
The RNA polymerase III (Pol III) transcriptome is universally comprised of short, highly structured noncoding RNA (ncRNA). Through RNA-protein interactions, the Pol III transcriptome actuates functional activities ranging from nuclear gene regulation (7SK), splicing (U6, U6atac), and RNA maturation and stability (RMRP, RPPH1, Y RNA), to cytoplasmic protein targeting (7SL) and translation (tRNA, 5S rRNA). In higher eukaryotes, the Pol III transcriptome has expanded to include additional, recently evolved ncRNA species that effectively broaden the footprint of Pol III transcription to additional cellular activities. Newly evolved ncRNAs function as riboregulators of autophagy (vault), immune signaling cascades (nc886), and translation (Alu, BC200, snaR). Notably, upregulation of Pol III transcription is frequently observed in cancer, and multiple ncRNA species are linked to both cancer progression and poor survival outcomes among cancer patients. In this review, we outline the basic features and functions of the Pol III transcriptome, and the evidence for dysregulation and dysfunction for each ncRNA in cancer. When taken together, recurrent patterns emerge, ranging from shared functional motifs that include molecular scaffolding and protein sequestration, overlapping protein interactions, and immunostimulatory activities, to the biogenesis of analogous small RNA fragments and noncanonical miRNAs, augmenting the function of the Pol III transcriptome and further broadening its role in cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Processing of Small RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Sihang Zhou
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Kevin Van Bortle
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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13
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Tian K, Wang R, Huang J, Wang H, Ji X. Subcellular localization shapes the fate of RNA polymerase III. Cell Rep 2023; 42:112941. [PMID: 37556328 DOI: 10.1016/j.celrep.2023.112941] [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: 02/08/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/11/2023] Open
Abstract
RNA polymerase III (Pol III) plays a vital role in transcription and as a viral-DNA sensor, but how it is assembled and distributed within cells remains poorly understood. Here, we show that Pol III is assembled with chaperones in the cytoplasm and forms transcription-dependent protein clusters upon transport into the nucleus. The largest subunit (RPC1) depletion through an auxin-inducible degron leads to rapid degradation and disassembly of Pol III complex in the nucleus and cytoplasm, respectively. This generates a pool of partially assembled Pol III intermediates, which can be rapidly mobilized into the nucleus upon the restoration of RPC1. Our study highlights the critical role of subcellular localization in determining Pol III's fate and provides insight into the dynamic regulation of nuclear Pol III levels and the origin of cytoplasmic Pol III complexes involved in mediating viral immunity.
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Affiliation(s)
- 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
| | - Rui Wang
- 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
| | - Hui Wang
- 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
| | - 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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14
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Marques BL, Maciel GF, Brito MR, Dias LD, Scalzo S, Santos AK, Kihara AH, da Costa Santiago H, Parreira RC, Birbrair A, Resende RR. Regulatory mechanisms of stem cell differentiation: Biotechnological applications for neurogenesis. Semin Cell Dev Biol 2023; 144:11-19. [PMID: 36202693 DOI: 10.1016/j.semcdb.2022.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 09/20/2022] [Accepted: 09/27/2022] [Indexed: 12/15/2022]
Abstract
The world population's life expectancy is growing, and neurodegenerative disorders common in old age require more efficient therapies. In this context, neural stem cells (NSCs) are imperative for the development and maintenance of the functioning of the nervous system and have broad therapeutic applicability for neurodegenerative diseases. Therefore, knowing all the mechanisms that govern the self-renewal, differentiation, and cell signaling of NSC is necessary. This review will address some of these aspects, including the role of growth and transcription factors, epigenetic modulators, microRNAs, and extracellular matrix components. Furthermore, differentiation and transdifferentiation processes will be addressed as therapeutic strategies showing their significance for stem cell-based therapy.
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Affiliation(s)
- Bruno L Marques
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | | | - Marcello R Brito
- Centro Universitário de Mineiros - UNIFIMES, Campus Trindade, GO, Brazil
| | - Lucas D Dias
- Centro Universitário de Mineiros - UNIFIMES, Campus Trindade, GO, Brazil
| | - Sérgio Scalzo
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Anderson K Santos
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Alexandre Hiroaki Kihara
- Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Helton da Costa Santiago
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ricardo C Parreira
- Centro Universitário de Mineiros - UNIFIMES, Campus Trindade, GO, Brazil
| | - Alexander Birbrair
- Departamento de Patologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Rodrigo R Resende
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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15
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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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16
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Abstract
Although differential transcription drives the development of multicellular organisms, the ultimate readout of a protein-coding gene is ribosome-dependent mRNA translation. Ribosomes were once thought of as uniform molecular machines, but emerging evidence indicates that the complexity and diversity of ribosome biogenesis and function should be given a fresh look in the context of development. This Review begins with a discussion of different developmental disorders that have been linked with perturbations in ribosome production and function. We then highlight recent studies that reveal how different cells and tissues exhibit variable levels of ribosome production and protein synthesis, and how changes in protein synthesis capacity can influence specific cell fate decisions. We finish by touching upon ribosome heterogeneity in stress responses and development. These discussions highlight the importance of considering both ribosome levels and functional specialization in the context of development and disease.
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Affiliation(s)
- Chunyang Ni
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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17
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Zhang C, Zhao S, Deng H, Zhang S, Wang J, Song X, Yu D, Zhang Y, Deng W. STAT3 promotes RNA polymerase III-directed transcription by controlling the miR-106a-5p/TP73 axis. eLife 2023; 12:e82826. [PMID: 36656267 PMCID: PMC9851613 DOI: 10.7554/elife.82826] [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: 08/18/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Deregulation of Pol III products causes a range of diseases, including neural diseases and cancers. However, the factors and mechanisms that modulate Pol III-directed transcription remain to be found, although massive advances have been achieved. Here, we show that STAT3 positively regulates the activities of Pol III-dependent transcription and cancer cell growth. RNA-seq analysis revealed that STAT3 inhibits the expression of TP73, a member of the p53 family. We found that TP73 is not only required for the regulation of Pol III-directed transcription mediated by STAT3 but also independently suppresses the synthesis of Pol III products. Mechanistically, TP73 can disrupt the assembly of TFIIIB subunits and inhibit their occupancies at Pol III target loci by interacting with TFIIIB subunit TBP. MiR-106a-5p can activate Pol III-directed transcription by targeting the TP73 mRNA 3' UTR to reduce TP 73 expression. We show that STAT3 activates the expression of miR-106a-5p by binding to the miRNA promoter, indicating that the miR-106a-5p links STAT3 with TP73 to regulate Pol III-directed transcription. Collectively, these findings indicate that STAT3 functions as a positive regulator in Pol III-directed transcription by controlling the miR-106a-5p/TP73 axis.
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Affiliation(s)
- Cheng Zhang
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Shasha Zhao
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Huan Deng
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Shihua Zhang
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Juan Wang
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
- School of Materials and Metallurgy, Wuhan University of Science and TechnologyWuhanChina
| | - Xiaoye Song
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Deen Yu
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Yue Zhang
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
| | - Wensheng Deng
- School of Life Science and Health, Wuhan University of Science and TechnologyWuhanChina
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18
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Hori RT, Moshahid Khan M, Xiao J, Hargrove PW, Moss T, LeDoux MS. Behavioral and molecular effects of Ubtf knockout and knockdown in mice. Brain Res 2022; 1793:148053. [PMID: 35973608 PMCID: PMC10908547 DOI: 10.1016/j.brainres.2022.148053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/10/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022]
Abstract
The UBTF E210K neuroregression syndrome is caused by de novo dominant mutations in UBTF (NM_014233.3:c.628G > A, p.Glu210Lys). In humans, onset is typically at 2.5 to 3 years and characterized by slow progression of global motor, cognitive and behavioral dysfunction. Other potentially pathogenic UBTF variants have been reported in humans with severe neurological disease and it remains undetermined if the UBTF E210K mutation operates via gain- and/or loss-of-function. Here we examine the behavioral, cognitive, motor, and molecular effects of Ubtf knockout and knockdown in mice as a means of gauging the role of loss-of-function in humans. Ubtf+/- mice show progression of behavioral (dominance tube), cognitive (cross maze), and mild motor abnormalities from 3 to 18 months. At 18 months, Ubtf+/- mice had more slips on a raised 9-mm round beam task, shorter latencies to fall on the accelerated rotarod, reduced open field vertical and jump counts, and significant deficits in spatial learning and memory. Via crosses to Nestin-Cre (NesCre) mice we found that homozygous Ubtf deletion limited to the central nervous system was embryonic lethal. Tamoxifen-induced homozygous knockdown of Ubtf in adult mice with the Cre-ERT2 system was associated with precipitous deterioration in neurological functioning. At the molecular level, 18-month-old Ubtf+/- mice showed mild increases in cerebellar 53BP1 immunoreactivity. These findings show that UBTF is essential for embryogenesis and survival in adults, and the deleterious effects of UBTF haploinsufficiency progress with age. Loss-of-function mechanisms may contribute, in part, to the human UBTF E210K neuroregression syndrome.
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Affiliation(s)
- Roderick T Hori
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Mohammad Moshahid Khan
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Physical Therapy, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Jianfeng Xiao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Phillip W Hargrove
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Tom Moss
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, Canada
| | - Mark S LeDoux
- Department of Psychology, University of Memphis, Memphis, TN 38152, USA; Veracity Neuroscience, Memphis, TN, 38157, USA.
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19
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Buszczak M. Ribosome homeostasis. Semin Cell Dev Biol 2022; 136:1-2. [PMID: 35909032 DOI: 10.1016/j.semcdb.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
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