1
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Xu GE, Zhao X, Li G, Gokulnath P, Wang L, Xiao J. The landscape of epigenetic regulation and therapeutic application of N 6-methyladenosine modifications in non-coding RNAs. Genes Dis 2024; 11:101045. [PMID: 38988321 PMCID: PMC11233902 DOI: 10.1016/j.gendis.2023.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 05/18/2023] [Accepted: 06/04/2023] [Indexed: 07/12/2024] Open
Abstract
RNA N6-methyladenosine (m6A) methylation is the most abundant and conserved RNA modification in eukaryotes. It participates in the regulation of RNA metabolism and various pathophysiological processes. Non-coding RNAs (ncRNAs) are defined as small or long transcripts which do not encode proteins and display numerous biological regulatory functions. Similar to mRNAs, m6A deposition is observed in ncRNAs. Studying RNA m6A modifications on ncRNAs is of great importance specifically to deepen our understanding of their biological roles and clinical implications. In this review, we summarized the recent research findings regarding the mutual regulation between RNA m6A modification and ncRNAs (with a specific focus on microRNAs, long non-coding RNAs, and circular RNAs) and their functions. We also discussed the challenges of m6A-containing ncRNAs and RNA m6A as therapeutic targets in human diseases and their future perspective in translational roles.
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Affiliation(s)
- Gui-E Xu
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong) and School of Life Sciences, Shanghai University, Nantong, Jiangsu 226011, China
- Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China
| | - Xuan Zhao
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong) and School of Life Sciences, Shanghai University, Nantong, Jiangsu 226011, China
- Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China
| | - Guoping Li
- Cardiovascular Division of the Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Priyanka Gokulnath
- Cardiovascular Division of the Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Lijun Wang
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong) and School of Life Sciences, Shanghai University, Nantong, Jiangsu 226011, China
- Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China
| | - Junjie Xiao
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong) and School of Life Sciences, Shanghai University, Nantong, Jiangsu 226011, China
- Cardiac Regeneration and Ageing Lab, Institute of Cardiovascular Sciences, Shanghai Engineering Research Center of Organ Repair, School of Life Science, Shanghai University, Shanghai 200444, China
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2
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Dror I, Tan T, Plath K. A critical role for X-chromosome architecture in mammalian X-chromosome dosage compensation. Curr Opin Genet Dev 2024; 87:102235. [PMID: 39053028 DOI: 10.1016/j.gde.2024.102235] [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: 04/20/2024] [Revised: 07/02/2024] [Accepted: 07/05/2024] [Indexed: 07/27/2024]
Abstract
To regulate gene expression, the macromolecular components of the mammalian interphase nucleus are spatially organized into a myriad of functional compartments. Over the past decade, increasingly sophisticated genomics, microscopy, and functional approaches have probed this organization in unprecedented detail. These investigations have linked chromatin-associated noncoding RNAs to specific nuclear compartments and uncovered mechanisms by which these RNAs establish such domains. In this review, we focus on the long non-coding RNA Xist and summarize new evidence demonstrating the significance of chromatin reconfiguration in creating the inactive X-chromosome compartment. Differences in chromatin compaction correlate with distinct levels of gene repression on the X-chromosome, potentially explaining how human XIST can induce chromosome-wide dampening and silencing of gene expression at different stages of human development.
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Affiliation(s)
- Iris Dror
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Tiao Tan
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Kathrin Plath
- Department of Biological Chemistry, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, Jonsson Comprehensive Cancer Center, Brain Research Institute, Graduate Program in the Biosciences, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA.
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3
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Zhu Z, Younas L, Zhou Q. Evolution and regulation of animal sex chromosomes. Nat Rev Genet 2024:10.1038/s41576-024-00757-3. [PMID: 39026082 DOI: 10.1038/s41576-024-00757-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
Animal sex chromosomes typically carry the upstream sex-determining gene that triggers testis or ovary development and, in some species, are regulated by global dosage compensation in response to functional decay of the Y chromosome. Despite the importance of these pathways, they exhibit striking differences across species, raising fundamental questions regarding the mechanisms underlying their evolutionary turnover. Recent studies of non-model organisms, including insects, reptiles and teleosts, have yielded a broad view of the diversity of sex chromosomes that challenges established theories. Moreover, continued studies in model organisms with recently developed technologies have characterized the dynamics of sex determination and dosage compensation in three-dimensional nuclear space and at single-cell resolution. Here, we synthesize recent insights into sex chromosomes from a variety of species to review their evolutionary dynamics with respect to the canonical model, as well as their diverse mechanisms of regulation.
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Affiliation(s)
- Zexian Zhu
- Evolutionary and Organismal Biology Research Center and Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lubna Younas
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Qi Zhou
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China.
- State Key Laboratory of Transvascular Implantation Devices, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
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4
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Condemi L, Mocavini I, Aranda S, Di Croce L. Polycomb function in early mouse development. Cell Death Differ 2024:10.1038/s41418-024-01340-3. [PMID: 38997437 DOI: 10.1038/s41418-024-01340-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/14/2024] Open
Abstract
Epigenetic factors are crucial for ensuring proper chromatin dynamics during the initial stages of embryo development. Among these factors, the Polycomb group (PcG) of proteins plays a key role in establishing correct transcriptional programmes during mouse embryogenesis. PcG proteins are classified into two complexes: Polycomb repressive complex 1 (PRC1) and PRC2. Both complexes decorate histone proteins with distinct post-translational modifications (PTMs) that are predictive of a silent transcriptional chromatin state. In recent years, a critical adaptation of the classical techniques to analyse chromatin profiles and to study biochemical interactions at low-input resolution has allowed us to deeply explore PcG molecular mechanisms in the very early stages of mouse embryo development- from fertilisation to gastrulation, and from zygotic genome activation (ZGA) to specific lineages differentiation. These advancements provide a foundation for a deeper understanding of the fundamental role Polycomb complexes play in early development and have elucidated the mechanistic dynamics of PRC1 and PRC2. In this review, we discuss the functions and molecular mechanisms of both PRC1 and PRC2 during early mouse embryo development, integrating new studies with existing knowledge. Furthermore, we highlight the molecular functionality of Polycomb complexes from ZGA through gastrulation, with a particular focus on non-canonical imprinted and bivalent genes, and Hox cluster regulation.
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Affiliation(s)
- Livia Condemi
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Ivano Mocavini
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA
| | - Sergi Aranda
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain.
- Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- ICREA, Pg. Lluis Companys 23, 08010, Barcelona, Spain.
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5
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Cao Y, Qiu G, Dong Y, Zhao W, Wang Y. Exploring the role of m 6 A writer RBM15 in cancer: a systematic review. Front Oncol 2024; 14:1375942. [PMID: 38915367 PMCID: PMC11194397 DOI: 10.3389/fonc.2024.1375942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/17/2024] [Indexed: 06/26/2024] Open
Abstract
In the contemporary epoch, cancer stands as the predominant cause of premature global mortality, necessitating a focused exploration of molecular markers and advanced therapeutic strategies. N6-methyladenosine (m6A), the most prevalent mRNA modification, undergoes dynamic regulation by enzymes referred to as methyltransferases (writers), demethylases (erasers), and effective proteins (readers). Despite lacking methylation activity, RNA-binding motif protein 15 (RBM15), a member of the m6A writer family, assumes a crucial role in recruiting the methyltransferase complex (MTC) and binding to mRNA. Although the impact of m6A modifications on cancer has garnered widespread attention, RBM15 has been relatively overlooked. This review briefly outlines the structure and operational mechanism, and delineates the unique role of RBM15 in various cancers, shedding light on its molecular basis and providing a groundwork for potential tumor-targeted therapies.
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Affiliation(s)
- Yuan Cao
- Fourth Department of Orthopedic Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
| | - Guanzhen Qiu
- Fourth Department of Orthopedic Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
- Shenyang 242 Hospital, Shenyang, Liaoning, China
| | - Yu Dong
- Fourth Department of Orthopedic Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
| | - Wei Zhao
- Fourth Department of Orthopedic Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
| | - Yong Wang
- Fourth Department of Orthopedic Surgery, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
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6
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Bowness JS, Almeida M, Nesterova TB, Brockdorff N. YY1 binding is a gene-intrinsic barrier to Xist-mediated gene silencing. EMBO Rep 2024; 25:2258-2277. [PMID: 38654121 PMCID: PMC11094009 DOI: 10.1038/s44319-024-00136-3] [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: 02/23/2024] [Revised: 03/26/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
X chromosome inactivation (XCI) in mammals is mediated by Xist RNA which functions in cis to silence genes on a single X chromosome in XX female cells, thereby equalising levels of X-linked gene expression relative to XY males. XCI progresses over a period of several days, with some X-linked genes silencing faster than others. The chromosomal location of a gene is an important determinant of silencing rate, but uncharacterised gene-intrinsic features also mediate resistance or susceptibility to silencing. In this study, we examine mouse embryonic stem cell lines with an inducible Xist allele (iXist-ChrX mESCs) and integrate allele-specific data of gene silencing and decreasing inactive X (Xi) chromatin accessibility over time courses of Xist induction with cellular differentiation. Our analysis reveals that motifs bound by the transcription factor YY1 are associated with persistently accessible regulatory elements, including many promoters and enhancers of slow-silencing genes. We further show that YY1 is evicted relatively slowly from target sites on Xi, and that silencing of X-linked genes is increased upon YY1 degradation. Together our results suggest that YY1 acts as a barrier to Xist-mediated silencing until the late stages of the XCI process.
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Affiliation(s)
- Joseph S Bowness
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Mafalda Almeida
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | | | - Neil Brockdorff
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
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7
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Zacco E, Broglia L, Kurihara M, Monti M, Gustincich S, Pastore A, Plath K, Nagakawa S, Cerase A, Sanchez de Groot N, Tartaglia GG. RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding. Chem Rev 2024; 124:4734-4777. [PMID: 38579177 PMCID: PMC11046439 DOI: 10.1021/acs.chemrev.3c00575] [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: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 04/07/2024]
Abstract
This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences. By deepening our understanding of the delicate balance that governs molecular crowding driven by RNA and its implications for cellular homeostasis, we aim to shed light on this intriguing area of research. Our exploration extends to the methodologies employed to decipher the composition and structural intricacies of RNA granules, offering a comprehensive overview of the techniques used to characterize them, including relevant computational approaches. Through two detailed examples highlighting the significance of noncoding RNAs, NEAT1 and XIST, in the formation of phase-separated assemblies and their influence on the cellular landscape, we emphasize their crucial role in cellular organization and function. By elucidating the chemical underpinnings of RNA-mediated molecular crowding, investigating the role of modifications, structures, and composition of RNA granules, and exploring both physiological and aberrant phase separation phenomena, this Review provides a multifaceted understanding of the intriguing world of RNA-mediated biological condensates.
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Affiliation(s)
- Elsa Zacco
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Laura Broglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Misuzu Kurihara
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Michele Monti
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Stefano Gustincich
- Central
RNA Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Annalisa Pastore
- UK
Dementia Research Institute at the Maurice Wohl Institute of King’s
College London, London SE5 9RT, U.K.
| | - Kathrin Plath
- Department
of Biological Chemistry, David Geffen School
of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shinichi Nagakawa
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Andrea Cerase
- Blizard
Institute,
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, U.K.
- Unit
of Cell and developmental Biology, Department of Biology, Università di Pisa, 56123 Pisa, Italy
| | - Natalia Sanchez de Groot
- Unitat
de Bioquímica, Departament de Bioquímica i Biologia
Molecular, Universitat Autònoma de
Barcelona, 08193 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
- Catalan
Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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8
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Malcore RM, Kalantry S. A Comparative Analysis of Mouse Imprinted and Random X-Chromosome Inactivation. EPIGENOMES 2024; 8:8. [PMID: 38390899 PMCID: PMC10885068 DOI: 10.3390/epigenomes8010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
The mammalian sexes are distinguished by the X and Y chromosomes. Whereas males harbor one X and one Y chromosome, females harbor two X chromosomes. To equalize X-linked gene expression between the sexes, therian mammals have evolved X-chromosome inactivation as a dosage compensation mechanism. During X-inactivation, most genes on one of the two X chromosomes in females are transcriptionally silenced, thus equalizing X-linked gene expression between the sexes. Two forms of X-inactivation characterize eutherian mammals, imprinted and random. Imprinted X-inactivation is defined by the exclusive inactivation of the paternal X chromosome in all cells, whereas random X-inactivation results in the silencing of genes on either the paternal or maternal X chromosome in individual cells. Both forms of X-inactivation have been studied intensively in the mouse model system, which undergoes both imprinted and random X-inactivation early in embryonic development. Stable imprinted and random X-inactivation requires the induction of the Xist long non-coding RNA. Following its induction, Xist RNA recruits proteins and complexes that silence genes on the inactive-X. In this review, we present a current understanding of the mechanisms of Xist RNA induction, and, separately, the establishment and maintenance of gene silencing on the inactive-X by Xist RNA during imprinted and random X-inactivation.
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Affiliation(s)
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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9
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Dror I, Chitiashvili T, Tan SYX, Cano CT, Sahakyan A, Markaki Y, Chronis C, Collier AJ, Deng W, Liang G, Sun Y, Afasizheva A, Miller J, Xiao W, Black DL, Ding F, Plath K. XIST directly regulates X-linked and autosomal genes in naive human pluripotent cells. Cell 2024; 187:110-129.e31. [PMID: 38181737 PMCID: PMC10783549 DOI: 10.1016/j.cell.2023.11.033] [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: 12/21/2020] [Revised: 04/01/2023] [Accepted: 11/28/2023] [Indexed: 01/07/2024]
Abstract
X chromosome inactivation (XCI) serves as a paradigm for RNA-mediated regulation of gene expression, wherein the long non-coding RNA XIST spreads across the X chromosome in cis to mediate gene silencing chromosome-wide. In female naive human pluripotent stem cells (hPSCs), XIST is in a dispersed configuration, and XCI does not occur, raising questions about XIST's function. We found that XIST spreads across the X chromosome and induces dampening of X-linked gene expression in naive hPSCs. Surprisingly, XIST also targets specific autosomal regions, where it induces repressive chromatin changes and gene expression dampening. Thereby, XIST equalizes X-linked gene dosage between male and female cells while inducing differences in autosomes. The dispersed Xist configuration and autosomal localization also occur transiently during XCI initiation in mouse PSCs. Together, our study identifies XIST as the regulator of X chromosome dampening, uncovers an evolutionarily conserved trans-acting role of XIST/Xist, and reveals a correlation between XIST/Xist dispersal and autosomal targeting.
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Affiliation(s)
- Iris Dror
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tsotne Chitiashvili
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Shawn Y X Tan
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Clara T Cano
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anna Sahakyan
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yolanda Markaki
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute for Structural and Chemical Biology & Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Constantinos Chronis
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Amanda J Collier
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Weixian Deng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Guohao Liang
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Yu Sun
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anna Afasizheva
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jarrett Miller
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wen Xiao
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Douglas L Black
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Fangyuan Ding
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA; Department of Developmental and Cell Biology, Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Kathrin Plath
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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10
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Peeters SB, Posynick BJ, Brown CJ. Out of the Silence: Insights into How Genes Escape X-Chromosome Inactivation. EPIGENOMES 2023; 7:29. [PMID: 38131901 PMCID: PMC10742877 DOI: 10.3390/epigenomes7040029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
The silencing of all but one X chromosome in mammalian cells is a remarkable epigenetic process leading to near dosage equivalence in X-linked gene products between the sexes. However, equally remarkable is the ability of a subset of genes to continue to be expressed from the otherwise inactive X chromosome-in some cases constitutively, while other genes are variable between individuals, tissues or cells. In this review we discuss the advantages and disadvantages of the approaches that have been used to identify escapees. The identity of escapees provides important clues to mechanisms underlying escape from XCI, an arena of study now moving from correlation to functional studies. As most escapees show greater expression in females, the not-so-inactive X chromosome is a substantial contributor to sex differences in humans, and we highlight some examples of such impact.
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Affiliation(s)
| | | | - Carolyn J. Brown
- Molecular Epigenetics Group, Department of Medical Genetics, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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11
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Keniry A, Blewitt ME. Chromatin-mediated silencing on the inactive X chromosome. Development 2023; 150:dev201742. [PMID: 37991053 DOI: 10.1242/dev.201742] [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] [Indexed: 11/23/2023]
Abstract
In mammals, the second X chromosome in females is silenced to enable dosage compensation between XX females and XY males. This essential process involves the formation of a dense chromatin state on the inactive X (Xi) chromosome. There is a wealth of information about the hallmarks of Xi chromatin and the contribution each makes to silencing, leaving the tantalising possibility of learning from this knowledge to potentially remove silencing to treat X-linked diseases in females. Here, we discuss the role of each chromatin feature in the establishment and maintenance of the silent state, which is of crucial relevance for such a goal.
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Affiliation(s)
- Andrew Keniry
- Epigenetics and Development Division, The Walter and Eliza Hall Institute for Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia
- The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Marnie E Blewitt
- Epigenetics and Development Division, The Walter and Eliza Hall Institute for Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia
- The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
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12
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Kaufmann C, Wutz A. IndiSPENsable for X Chromosome Inactivation and Gene Silencing. EPIGENOMES 2023; 7:28. [PMID: 37987303 PMCID: PMC10660550 DOI: 10.3390/epigenomes7040028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/22/2023] Open
Abstract
For about 30 years, SPEN has been the subject of research in many different fields due to its variety of functions and its conservation throughout a wide spectrum of species, like worms, arthropods, and vertebrates. To date, 216 orthologues have been documented. SPEN had been studied for its role in gene regulation in the context of cell signaling, including the NOTCH or nuclear hormone receptor signaling pathways. More recently, SPEN has been identified as a major regulator of initiation of chromosome-wide gene silencing during X chromosome inactivation (XCI) in mammals, where its function remains to be fully understood. Dependent on the biological context, SPEN functions via mechanisms which include different domains. While some domains of SPEN are highly conserved in sequence and secondary structure, species-to-species differences exist that might lead to mechanistic differences. Initiation of XCI appears to be different between humans and mice, which raises additional questions about the extent of generalization of SPEN's function in XCI. In this review, we dissect the mechanism of SPEN in XCI. We discuss its subregions and domains, focusing on its role as a major regulator. We further highlight species-related research, specifically of mouse and human SPEN, with the aim to reveal and clarify potential species-to-species differences in SPEN's function.
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Affiliation(s)
| | - Anton Wutz
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology ETH Hönggerberg, 8093 Zurich, Switzerland;
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13
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Agostinho de Sousa J, Wong CW, Dunkel I, Owens T, Voigt P, Hodgson A, Baker D, Schulz EG, Reik W, Smith A, Rostovskaya M, von Meyenn F. Epigenetic dynamics during capacitation of naïve human pluripotent stem cells. SCIENCE ADVANCES 2023; 9:eadg1936. [PMID: 37774033 PMCID: PMC10541016 DOI: 10.1126/sciadv.adg1936] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 08/30/2023] [Indexed: 10/01/2023]
Abstract
Human pluripotent stem cells (hPSCs) are of fundamental relevance in regenerative medicine. Naïve hPSCs hold promise to overcome some of the limitations of conventional (primed) hPSCs, including recurrent epigenetic anomalies. Naïve-to-primed transition (capacitation) follows transcriptional dynamics of human embryonic epiblast and is necessary for somatic differentiation from naïve hPSCs. We found that capacitated hPSCs are transcriptionally closer to postimplantation epiblast than conventional hPSCs. This prompted us to comprehensively study epigenetic and related transcriptional changes during capacitation. Our results show that CpG islands, gene regulatory elements, and retrotransposons are hotspots of epigenetic dynamics during capacitation and indicate possible distinct roles of specific epigenetic modifications in gene expression control between naïve and primed hPSCs. Unexpectedly, PRC2 activity appeared to be dispensable for the capacitation. We find that capacitated hPSCs acquire an epigenetic state similar to conventional hPSCs. Significantly, however, the X chromosome erosion frequently observed in conventional female hPSCs is reversed by resetting and subsequent capacitation.
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Affiliation(s)
- João Agostinho de Sousa
- Laboratory of Nutrition and Metabolic Epigenetics, Department of Health Sciences and Technology, ETH Zurich, 8603 Schwerzenbach, Switzerland
| | - Chee-Wai Wong
- Laboratory of Nutrition and Metabolic Epigenetics, Department of Health Sciences and Technology, ETH Zurich, 8603 Schwerzenbach, Switzerland
| | - Ilona Dunkel
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Thomas Owens
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Philipp Voigt
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Adam Hodgson
- School of Biosciences, The Julia Garnham Centre, University of Sheffield, S10 2TN Sheffield, UK
| | - Duncan Baker
- Sheffield Diagnostic Genetics Services, Sheffield Children’s NHS Foundation Trust, S5 7AU Sheffield, UK
| | - Edda G. Schulz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Wolf Reik
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1QR, UK
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, UK
- Altos Labs Cambridge Institute of Science, Cambridge CB21 6GP, UK
| | - Austin Smith
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
- Living Systems Institute, University of Exeter, EX4 4QD Exeter, UK
| | - Maria Rostovskaya
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Ferdinand von Meyenn
- Laboratory of Nutrition and Metabolic Epigenetics, Department of Health Sciences and Technology, ETH Zurich, 8603 Schwerzenbach, Switzerland
- Department of Medical and Molecular Genetics, King’s College London, Guy’s Hospital, SE1 9RT London, UK
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14
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Valledor M, Byron M, Dumas B, Carone DM, Hall LL, Lawrence JB. Early chromosome condensation by XIST builds A-repeat RNA density that facilitates gene silencing. Cell Rep 2023; 42:112686. [PMID: 37384527 PMCID: PMC10461597 DOI: 10.1016/j.celrep.2023.112686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 10/31/2022] [Accepted: 06/08/2023] [Indexed: 07/01/2023] Open
Abstract
XIST RNA triggers chromosome-wide gene silencing and condenses an active chromosome into a Barr body. Here, we use inducible human XIST to examine early steps in the process, showing that XIST modifies cytoarchitecture before widespread gene silencing. In just 2-4 h, barely visible transcripts populate the large "sparse zone" surrounding the smaller "dense zone"; importantly, density zones exhibit different chromatin impacts. Sparse transcripts immediately trigger immunofluorescence for H2AK119ub and CIZ1, a matrix protein. H3K27me3 appears hours later in the dense zone, which enlarges with chromosome condensation. Genes examined are silenced after compaction of the RNA/DNA territory. Insights into this come from the findings that the A-repeat alone can silence genes and rapidly, but only where dense RNA supports sustained histone deacetylation. We propose that sparse XIST RNA quickly impacts architectural elements to condense the largely non-coding chromosome, coalescing RNA density that facilitates an unstable, A-repeat-dependent step required for gene silencing.
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Affiliation(s)
- Melvys Valledor
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Meg Byron
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Brett Dumas
- Department of Medicine, Boston University Medical Center, Boston, MA 02118, USA
| | - Dawn M Carone
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Lisa L Hall
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
| | - Jeanne B Lawrence
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA; Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
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15
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Singh A, Rappolee DA, Ruden DM. Epigenetic Reprogramming in Mice and Humans: From Fertilization to Primordial Germ Cell Development. Cells 2023; 12:1874. [PMID: 37508536 PMCID: PMC10377882 DOI: 10.3390/cells12141874] [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: 05/01/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
In this review, advances in the understanding of epigenetic reprogramming from fertilization to the development of primordial germline cells in a mouse and human embryo are discussed. To gain insights into the molecular underpinnings of various diseases, it is essential to comprehend the intricate interplay between genetic, epigenetic, and environmental factors during cellular reprogramming and embryonic differentiation. An increasing range of diseases, including cancer and developmental disorders, have been linked to alterations in DNA methylation and histone modifications. Global epigenetic reprogramming occurs in mammals at two stages: post-fertilization and during the development of primordial germ cells (PGC). Epigenetic reprogramming after fertilization involves rapid demethylation of the paternal genome mediated through active and passive DNA demethylation, and gradual demethylation in the maternal genome through passive DNA demethylation. The de novo DNA methyltransferase enzymes, Dnmt3a and Dnmt3b, restore DNA methylation beginning from the blastocyst stage until the formation of the gastrula, and DNA maintenance methyltransferase, Dnmt1, maintains methylation in the somatic cells. The PGC undergo a second round of global demethylation after allocation during the formative pluripotent stage before gastrulation, where the imprints and the methylation marks on the transposable elements known as retrotransposons, including long interspersed nuclear elements (LINE-1) and intracisternal A-particle (IAP) elements are demethylated as well. Finally, DNA methylation is restored in the PGC at the implantation stage including sex-specific imprints corresponding to the sex of the embryo. This review introduces a novel perspective by uncovering how toxicants and stress stimuli impact the critical period of allocation during formative pluripotency, potentially influencing both the quantity and quality of PGCs. Furthermore, the comprehensive comparison of epigenetic events between mice and humans breaks new ground, empowering researchers to make informed decisions regarding the suitability of mouse models for their experiments.
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Affiliation(s)
- Aditi Singh
- CS Mott Center, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (A.S.); (D.A.R.)
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48202, USA
| | - Daniel A. Rappolee
- CS Mott Center, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (A.S.); (D.A.R.)
- Reproductive Stress Measurement, Mechanisms and Management, Corp., 135 Lake Shore Rd., Grosse Pointe Farms, MI 48236, USA
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA
- Department of Physiology, Wayne State University, Detroit, MI 48202, USA
| | - Douglas M. Ruden
- CS Mott Center, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48202, USA; (A.S.); (D.A.R.)
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48202, USA
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48202, USA
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16
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Amicone L, Marchetti A, Cicchini C. The lncRNA HOTAIR: a pleiotropic regulator of epithelial cell plasticity. J Exp Clin Cancer Res 2023; 42:147. [PMID: 37308974 DOI: 10.1186/s13046-023-02725-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/30/2023] [Indexed: 06/14/2023] Open
Abstract
The epithelial-to-mesenchymal transition (EMT) is a trans-differentiation process that endows epithelial cells with mesenchymal properties, including motility and invasion capacity; therefore, its aberrant reactivation in cancerous cells represents a critical step to gain a metastatic phenotype. The EMT is a dynamic program of cell plasticity; many partial EMT states can be, indeed, encountered and the full inverse mesenchymal-to-epithelial transition (MET) appears fundamental to colonize distant secondary sites. The EMT/MET dynamics is granted by a fine modulation of gene expression in response to intrinsic and extrinsic signals. In this complex scenario, long non-coding RNAs (lncRNAs) emerged as critical players. This review specifically focuses on the lncRNA HOTAIR, as a master regulator of epithelial cell plasticity and EMT in tumors. Molecular mechanisms controlling its expression in differentiated as well as trans-differentiated epithelial cells are highlighted here. Moreover, current knowledge about HOTAIR pleiotropic functions in regulation of both gene expression and protein activities are described. Furthermore, the relevance of the specific HOTAIR targeting and the current challenges of exploiting this lncRNA for therapeutic approaches to counteract the EMT are discussed.
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Affiliation(s)
- Laura Amicone
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Medicina Molecolare, Sapienza University of Rome, Viale Regina Elena 324, Rome, 00161, Italy
| | - Alessandra Marchetti
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Medicina Molecolare, Sapienza University of Rome, Viale Regina Elena 324, Rome, 00161, Italy
| | - Carla Cicchini
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Medicina Molecolare, Sapienza University of Rome, Viale Regina Elena 324, Rome, 00161, Italy.
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17
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Peeters S, Leung T, Fornes O, Farkas R, Wasserman W, Brown C. Refining the genomic determinants underlying escape from X-chromosome inactivation. NAR Genom Bioinform 2023; 5:lqad052. [PMID: 37260510 PMCID: PMC10227363 DOI: 10.1093/nargab/lqad052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/01/2023] [Accepted: 05/19/2023] [Indexed: 06/02/2023] Open
Abstract
X-chromosome inactivation (XCI) epigenetically silences one X chromosome in every cell in female mammals. Although the majority of X-linked genes are silenced, in humans 20% or more are able to escape inactivation and continue to be expressed. Such escape genes are important contributors to sex differences in gene expression, and may impact the phenotypes of X aneuploidies; yet the mechanisms regulating escape from XCI are not understood. We have performed an enrichment analysis of transcription factor binding on the X chromosome, providing new evidence for enriched factors at the transcription start sites of escape genes. The top escape-enriched transcription factors were detected at the RPS4X promoter, a well-described human escape gene previously demonstrated to escape from XCI in a transgenic mouse model. Using a cell line model system that allows for targeted integration and inactivation of transgenes on the mouse X chromosome, we further assessed combinations of RPS4X promoter and genic elements for their ability to drive escape from XCI. We identified a small transgenic construct of only 6 kb capable of robust escape from XCI, establishing that gene-proximal elements are sufficient to permit escape, and highlighting the additive effect of multiple elements that work together in a context-specific fashion.
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Affiliation(s)
- Samantha Peeters
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tiffany Leung
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Oriol Fornes
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachelle A Farkas
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wyeth W Wasserman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carolyn J Brown
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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18
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Zhu X, Zhou C, Zhao S, Zheng Z. Role of m6A methylation in retinal diseases. Exp Eye Res 2023; 231:109489. [PMID: 37084873 DOI: 10.1016/j.exer.2023.109489] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 03/06/2023] [Accepted: 04/19/2023] [Indexed: 04/23/2023]
Abstract
Retinal diseases remain among the leading causes of visual impairment in developed countries, despite great efforts in prevention and early intervention. Due to the limited efficacy of current retinal therapies, novel therapeutic methods are urgently required. Over the past two decades, advances in next-generation sequencing technology have facilitated research on RNA modifications, which can elucidate the relevance of epigenetic mechanisms to disease. N6-methyladenosine (m6A), formed by methylation of adenosine at the N6-position, is the most widely studied RNA modification and plays an important role in RNA metabolism. It is dynamically regulated by writers (methyltransferases) and erasers (demethylases), and recognized by readers (m6A binding proteins). Although the discovery of m6A methylation can be traced back to the 1970s, its regulatory roles in retinal diseases are rarely appreciated. Here, we provide an overview of m6A methylation, and discuss its effects and possible mechanisms on retinal diseases, including diabetic retinopathy, age-related macular degeneration, retinoblastoma, retinitis pigmentosa, and proliferative vitreoretinopathy. Furthermore, we highlight potential agents targeting m6A methylation for retinal disease treatment and discuss the limitations and challenges of research in the field of m6A methylation.
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Affiliation(s)
- Xinyu Zhu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Chuandi Zhou
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China
| | - Shuzhi Zhao
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China.
| | - Zhi Zheng
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China; National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, 200080, China.
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19
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Nickbarg EB, Spencer KB, Mortison JD, Lee JT. Targeting RNA with small molecules: lessons learned from Xist RNA. RNA (NEW YORK, N.Y.) 2023; 29:463-472. [PMID: 36725318 PMCID: PMC10019374 DOI: 10.1261/rna.079523.122] [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] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Although more than 98% of the human genome is noncoding, nearly all drugs on the market target one of about 700 disease-related proteins. However, an increasing number of diseases are now being attributed to noncoding RNA and the ability to target them would vastly expand the chemical space for drug development. We recently devised a screening strategy based upon affinity-selection mass spectrometry and succeeded in identifying bioactive compounds for the noncoding RNA prototype, Xist. One such compound, termed X1, has drug-like properties and binds specifically to the RepA motif of Xist in vitro and in vivo. Small-angle X-ray scattering analysis reveals that X1 changes the conformation of RepA in solution, thereby explaining the displacement of cognate interacting protein factors (PRC2 and SPEN) and inhibition of X-chromosome inactivation. In this Perspective, we discuss lessons learned from these proof-of-concept experiments and suggest that RNA can be systematically targeted by drug-like compounds to disrupt RNA structure and function.
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Affiliation(s)
| | | | | | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Appel LM, Benedum J, Engl M, Platzer S, Schleiffer A, Strobl X, Slade D. SPOC domain proteins in health and disease. Genes Dev 2023; 37:140-170. [PMID: 36927757 PMCID: PMC10111866 DOI: 10.1101/gad.350314.122] [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] [Indexed: 03/18/2023]
Abstract
Since it was first described >20 yr ago, the SPOC domain (Spen paralog and ortholog C-terminal domain) has been identified in many proteins all across eukaryotic species. SPOC-containing proteins regulate gene expression on various levels ranging from transcription to RNA processing, modification, export, and stability, as well as X-chromosome inactivation. Their manifold roles in controlling transcriptional output implicate them in a plethora of developmental processes, and their misregulation is often associated with cancer. Here, we provide an overview of the biophysical properties of the SPOC domain and its interaction with phosphorylated binding partners, the phylogenetic origin of SPOC domain proteins, the diverse functions of mammalian SPOC proteins and their homologs, the mechanisms by which they regulate differentiation and development, and their roles in cancer.
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Affiliation(s)
- Lisa-Marie Appel
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
| | - Johannes Benedum
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Magdalena Engl
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Sebastian Platzer
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), 1030 Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Xué Strobl
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Dea Slade
- Department of Radiation Oncology, Medical University of Vienna, 1090 Vienna, Austria;
- Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Laboratories, Vienna Biocenter, 1030 Vienna, Austria
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21
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Abstract
N6-Methyladenosine (m6A) is one of the most abundant modifications of the epitranscriptome and is found in cellular RNAs across all kingdoms of life. Advances in detection and mapping methods have improved our understanding of the effects of m6A on mRNA fate and ribosomal RNA function, and have uncovered novel functional roles in virtually every species of RNA. In this Review, we explore the latest studies revealing roles for m6A-modified RNAs in chromatin architecture, transcriptional regulation and genome stability. We also summarize m6A functions in biological processes such as stem-cell renewal and differentiation, brain function, immunity and cancer progression.
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Affiliation(s)
- Konstantinos Boulias
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Harvard Medical School Initiative for RNA Medicine, Boston, MA, USA
| | - Eric Lieberman Greer
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
- Harvard Medical School Initiative for RNA Medicine, Boston, MA, USA.
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22
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Dupont C, Schäffers OJ, Tan BF, Merzouk S, Bindels EM, Zwijsen A, Huylebroeck D, Gribnau J. Efficient generation of ETX embryoids that recapitulate the entire window of murine egg cylinder development. SCIENCE ADVANCES 2023; 9:eadd2913. [PMID: 36652512 PMCID: PMC9848479 DOI: 10.1126/sciadv.add2913] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
The murine embryonic-trophoblast-extra-embryonic endoderm (ETX) model is an integrated stem cell-based model to study early postimplantation development. It is based on the self-assembly potential of embryonic, trophoblast, and hypoblast/primitive/visceral endoderm-type stem cell lines (ESC, TSC, and XEN, respectively) to arrange into postimplantation egg cylinder-like embryoids. Here, we provide an optimized method for reliable and efficient generation of ETX embryoids that develop into late gastrulation in static culture conditions. It is based on transgenic Gata6-overproducing ESCs and modified assembly and culture conditions. Using this method, up to 43% of assembled ETX embryoids exhibited a correct spatial distribution of the three stem cell derivatives at day 4 of culture. Of those, 40% progressed into ETX embryoids that both transcriptionally and morphologically faithfully mimicked in vivo postimplantation mouse development between E5.5 and E7.5. The ETX model system offers the opportunity to study the murine postimplantation egg cylinder stages and could serve as a source of various cell lineage precursors.
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Affiliation(s)
- Cathérine Dupont
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Olivier J. M. Schäffers
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Obstetrics and Fetal Medicine, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Beatrice F. Tan
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Sarra Merzouk
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Eric M. Bindels
- Department of Hematology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - An Zwijsen
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Danny Huylebroeck
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
- Oncode Institute, Erasmus University Medical Center, Rotterdam, Netherlands
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23
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Appel LM, Franke V, Benedum J, Grishkovskaya I, Strobl X, Polyansky A, Ammann G, Platzer S, Neudolt A, Wunder A, Walch L, Kaiser S, Zagrovic B, Djinovic-Carugo K, Akalin A, Slade D. The SPOC domain is a phosphoserine binding module that bridges transcription machinery with co- and post-transcriptional regulators. Nat Commun 2023; 14:166. [PMID: 36631525 PMCID: PMC9834408 DOI: 10.1038/s41467-023-35853-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 01/05/2023] [Indexed: 01/13/2023] Open
Abstract
The heptad repeats of the C-terminal domain (CTD) of RNA polymerase II (Pol II) are extensively modified throughout the transcription cycle. The CTD coordinates RNA synthesis and processing by recruiting transcription regulators as well as RNA capping, splicing and 3'end processing factors. The SPOC domain of PHF3 was recently identified as a CTD reader domain specifically binding to phosphorylated serine-2 residues in adjacent CTD repeats. Here, we establish the SPOC domains of the human proteins DIDO, SHARP (also known as SPEN) and RBM15 as phosphoserine binding modules that can act as CTD readers but also recognize other phosphorylated binding partners. We report the crystal structure of SHARP SPOC in complex with CTD and identify the molecular determinants for its specific binding to phosphorylated serine-5. PHF3 and DIDO SPOC domains preferentially interact with the Pol II elongation complex, while RBM15 and SHARP SPOC domains engage with writers and readers of m6A, the most abundant RNA modification. RBM15 positively regulates m6A levels and mRNA stability in a SPOC-dependent manner, while SHARP SPOC is essential for its localization to inactive X-chromosomes. Our findings suggest that the SPOC domain is a major interface between the transcription machinery and regulators of transcription and co-transcriptional processes.
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Affiliation(s)
- Lisa-Marie Appel
- Department of Radiation Oncology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Vedran Franke
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Johannes Benedum
- Department of Radiation Oncology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Xué Strobl
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | - Anton Polyansky
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Gregor Ammann
- Department of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Sebastian Platzer
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Andrea Neudolt
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Anna Wunder
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Lena Walch
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Stefanie Kaiser
- Department of Pharmaceutical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Bojan Zagrovic
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Campus Vienna Biocenter 5, 1030, Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Vecčna Pot 113, 1000, Ljubljana, Slovenia
- European Molecular Biology Laboratory (EMBL) Grenoble, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, Cedex 9, France
| | - Altuna Akalin
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Dea Slade
- Department of Radiation Oncology, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.
- Comprehensive Cancer Center, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030, Vienna, Austria.
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24
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Masui O, Corbel C, Nagao K, Endo TA, Kezuka F, Diabangouaya P, Nakayama M, Kumon M, Koseki Y, Obuse C, Koseki H, Heard E. Polycomb repressive complexes 1 and 2 are each essential for maintenance of X inactivation in extra-embryonic lineages. Nat Cell Biol 2023; 25:134-144. [PMID: 36635505 DOI: 10.1038/s41556-022-01047-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/08/2022] [Indexed: 01/14/2023]
Abstract
In female mammals, one of the two X chromosomes becomes inactivated during development by X-chromosome inactivation (XCI). Although Polycomb repressive complex (PRC) 1 and PRC2 have both been implicated in gene silencing, their exact roles in XCI during in vivo development have remained elusive. To this end, we have studied mouse embryos lacking either PRC1 or PRC2. Here we demonstrate that the loss of either PRC has a substantial impact on maintenance of gene silencing on the inactive X chromosome (Xi) in extra-embryonic tissues, with overlapping yet different genes affected, indicating potentially independent roles of the two complexes. Importantly, a lack of PRC1 does not affect PRC2/H3K27me3 accumulation and a lack of PRC2 does not impact PRC1/H2AK119ub1 accumulation on the Xi. Thus PRC1 and PRC2 contribute independently to the maintenance of XCI in early post-implantation extra-embryonic lineages, revealing that both Polycomb complexes can be directly involved and differently deployed in XCI.
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Affiliation(s)
- Osamu Masui
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Catherine Corbel
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
| | - Koji Nagao
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Takaho A Endo
- Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Fuyuko Kezuka
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Patricia Diabangouaya
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
| | - Manabu Nakayama
- Laboratory of Medical Omics Research, Kazusa DNA Research Institute, Kisarazu, Japan
| | - Mami Kumon
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yoko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Haruhiko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan. .,Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
| | - Edith Heard
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France. .,Collège de France, Paris, France. .,European Molecular Biology Laboratory (EMBL), Directors' research unit, Heidelberg, Germany.
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25
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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26
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Porman AM, Roberts JT, Duncan ED, Chrupcala ML, Levine AA, Kennedy MA, Williams MM, Richer JK, Johnson AM. A single N6-methyladenosine site regulates lncRNA HOTAIR function in breast cancer cells. PLoS Biol 2022; 20:e3001885. [PMID: 36441764 PMCID: PMC9731500 DOI: 10.1371/journal.pbio.3001885] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/08/2022] [Accepted: 10/24/2022] [Indexed: 11/29/2022] Open
Abstract
N6-methyladenosine (m6A) modification of RNA regulates normal and cancer biology, but knowledge of its function on long noncoding RNAs (lncRNAs) remains limited. Here, we reveal that m6A regulates the breast cancer-associated human lncRNA HOTAIR. Mapping m6A in breast cancer cell lines, we identify multiple m6A sites on HOTAIR, with 1 single consistently methylated site (A783) that is critical for HOTAIR-driven proliferation and invasion of triple-negative breast cancer (TNBC) cells. Methylated A783 interacts with the m6A "reader" YTHDC1, promoting chromatin association of HOTAIR, proliferation and invasion of TNBC cells, and gene repression. A783U mutant HOTAIR induces a unique antitumor gene expression profile and displays loss-of-function and antimorph behaviors by impairing and, in some cases, causing opposite gene expression changes induced by wild-type (WT) HOTAIR. Our work demonstrates how modification of 1 base in an lncRNA can elicit a distinct gene regulation mechanism and drive cancer-associated phenotypes.
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Affiliation(s)
- Allison M. Porman
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
| | - Justin T. Roberts
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, Molecular Biology Graduate Program, Aurora, Colorado, United States of America
| | - Emily D. Duncan
- University of Colorado Anschutz Medical Campus, Molecular Biology Graduate Program, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, Cell and Developmental Biology Department, Aurora, Colorado, United States of America
| | - Madeline L. Chrupcala
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, RNA Bioscience Initiative, Aurora, Colorado, United States of America
| | - Ariel A. Levine
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, RNA Bioscience Initiative, Aurora, Colorado, United States of America
| | - Michelle A. Kennedy
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
| | - Michelle M. Williams
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jennifer K. Richer
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Aaron M. Johnson
- University of Colorado Anschutz Medical Campus, Biochemistry and Molecular Genetics Department, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, Molecular Biology Graduate Program, Aurora, Colorado, United States of America
- University of Colorado Anschutz Medical Campus, RNA Bioscience Initiative, Aurora, Colorado, United States of America
- * E-mail:
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27
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Lee S, Kim H, Hong A, Song J, Lee S, Kim M, Hwang SY, Jeong D, Kim J, Son A, Lee YS, Kim VN, Kim JS, Chang H, Ahn K. Functional and molecular dissection of HCMV long non-coding RNAs. Sci Rep 2022; 12:19303. [PMID: 36369338 PMCID: PMC9652368 DOI: 10.1038/s41598-022-23317-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/29/2022] [Indexed: 11/13/2022] Open
Abstract
Small, compact genomes confer a selective advantage to viruses, yet human cytomegalovirus (HCMV) expresses the long non-coding RNAs (lncRNAs); RNA1.2, RNA2.7, RNA4.9, and RNA5.0. Little is known about the function of these lncRNAs in the virus life cycle. Here, we dissected the functional and molecular landscape of HCMV lncRNAs. We found that HCMV lncRNAs occupy ~ 30% and 50-60% of total and poly(A)+viral transcriptome, respectively, throughout virus life cycle. RNA1.2, RNA2.7, and RNA4.9, the three abundantly expressed lncRNAs, appear to be essential in all infection states. Among these three lncRNAs, depletion of RNA2.7 and RNA4.9 results in the greatest defect in maintaining latent reservoir and promoting lytic replication, respectively. Moreover, we delineated the global post-transcriptional nature of HCMV lncRNAs by nanopore direct RNA sequencing and interactome analysis. We revealed that the lncRNAs are modified with N6-methyladenosine (m6A) and interact with m6A readers in all infection states. In-depth analysis demonstrated that m6A machineries stabilize HCMV lncRNAs, which could account for the overwhelming abundance of viral lncRNAs. Our study lays the groundwork for understanding the viral lncRNA-mediated regulation of host-virus interaction throughout the HCMV life cycle.
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Affiliation(s)
- Sungwon Lee
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Hyewon Kim
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Ari Hong
- grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea ,grid.31501.360000 0004 0470 5905Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jaewon Song
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Sungyul Lee
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Myeonghwan Kim
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Sung-yeon Hwang
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Dongjoon Jeong
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Jeesoo Kim
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Ahyeon Son
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Young-suk Lee
- grid.37172.300000 0001 2292 0500Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
| | - V. Narry Kim
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Jong-seo Kim
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
| | - Hyeshik Chang
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea ,grid.31501.360000 0004 0470 5905Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, 08826 Republic of Korea
| | - Kwangseog Ahn
- grid.31501.360000 0004 0470 5905School of Biological Sciences, Seoul National University, Seoul, 08826 Republic of Korea ,grid.410720.00000 0004 1784 4496Institute for Basic Science, Center for RNA Research, Seoul, 08826 Republic of Korea
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28
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Fernández-Justel JM, Santa-María C, Martín-Vírgala S, Ramesh S, Ferrera-Lagoa A, Salinas-Pena M, Isoler-Alcaraz J, Maslon MM, Jordan A, Cáceres JF, Gómez M. Histone H1 regulates non-coding RNA turnover on chromatin in a m6A-dependent manner. Cell Rep 2022; 40:111329. [PMID: 36103831 PMCID: PMC7613722 DOI: 10.1016/j.celrep.2022.111329] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 07/04/2022] [Accepted: 08/17/2022] [Indexed: 12/24/2022] Open
Abstract
Linker histones are highly abundant chromatin-associated proteins with well-established structural roles in chromatin and as general transcriptional repressors. In addition, it has been long proposed that histone H1 exerts context-specific effects on gene expression. Here, we identify a function of histone H1 in chromatin structure and transcription using a range of genomic approaches. In the absence of histone H1, there is an increase in the transcription of non-coding RNAs, together with reduced levels of m6A modification leading to their accumulation on chromatin and causing replication-transcription conflicts. This strongly suggests that histone H1 prevents non-coding RNA transcription and regulates non-coding transcript turnover on chromatin. Accordingly, altering the m6A RNA methylation pathway rescues the replicative phenotype of H1 loss. This work unveils unexpected regulatory roles of histone H1 on non-coding RNA turnover and m6A deposition, highlighting the intimate relationship between chromatin conformation, RNA metabolism, and DNA replication to maintain genome performance.
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Affiliation(s)
- José Miguel Fernández-Justel
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Cristina Santa-María
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Sara Martín-Vírgala
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Shreya Ramesh
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Alberto Ferrera-Lagoa
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Mónica Salinas-Pena
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Carrer de Baldiri Reixac, 15, 08028 Barcelona, Spain
| | - Javier Isoler-Alcaraz
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Magdalena M Maslon
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe South Road, Edinburgh EH4 2XU, UK
| | - Albert Jordan
- Instituto de Biología Molecular de Barcelona (IBMB-CSIC), Carrer de Baldiri Reixac, 15, 08028 Barcelona, Spain
| | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe South Road, Edinburgh EH4 2XU, UK
| | - María Gómez
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain.
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29
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Ichihara S, Nagao K, Sakaguchi T, Obuse C, Sado T. SmcHD1 underlies the formation of H3K9me3 blocks on the inactive X chromosome in mice. Development 2022; 149:dev200864. [PMID: 38771307 DOI: 10.1242/dev.200864] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/30/2022] [Indexed: 12/12/2022]
Abstract
Stable silencing of the inactive X chromosome (Xi) in female mammals is crucial for the development of embryos and their postnatal health. SmcHD1 is essential for stable silencing of the Xi, and its functional deficiency results in derepression of many X-inactivated genes. Although SmcHD1 has been suggested to play an important role in the formation of higher-order chromatin structure of the Xi, the underlying mechanism is largely unknown. Here, we explore the epigenetic state of the Xi in SmcHD1-deficient epiblast stem cells and mouse embryonic fibroblasts in comparison with their wild-type counterparts. The results suggest that SmcHD1 underlies the formation of H3K9me3-enriched blocks on the Xi, which, although the importance of H3K9me3 has been largely overlooked in mice, play a crucial role in the establishment of the stably silenced state. We propose that the H3K9me3 blocks formed on the Xi facilitate robust heterochromatin formation in combination with H3K27me3, and that the substantial loss of H3K9me3 caused by SmcHD1 deficiency leads to aberrant distribution of H3K27me3 on the Xi and derepression of X-inactivated genes.
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Affiliation(s)
- Saya Ichihara
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara 631-8505, Japan
| | - Koji Nagao
- Department of Biological Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Takehisa Sakaguchi
- Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Chikashi Obuse
- Department of Biological Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Takashi Sado
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University, Nara 631-8505, Japan
- Agricultural Technology and Innovation Research Institute, Kindai University, Nara 631-8505, Japan
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30
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Murakami S, Jaffrey SR. Hidden codes in mRNA: Control of gene expression by m 6A. Mol Cell 2022; 82:2236-2251. [PMID: 35714585 DOI: 10.1016/j.molcel.2022.05.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 12/13/2022]
Abstract
Information in mRNA has largely been thought to be confined to its nucleotide sequence. However, the advent of mapping techniques to detect modified nucleotides has revealed that mRNA contains additional information in the form of chemical modifications. The most abundant modified nucleotide is N6-methyladenosine (m6A), a methyl modification of adenosine. Although early studies viewed m6A as a dynamic and tissue-specific modification, it is now clear that the mRNAs that contain m6A and the location of m6A in those transcripts are largely universal and are influenced by gene architecture, i.e., the size and location of exons and introns. m6A can affect nuclear processes such as splicing and epigenetic regulation, but the major effect of m6A on mRNAs is to promote degradation in the cytoplasm. m6A marks a functionally related cohort of mRNAs linked to certain biological processes, including cell differentiation and cell fate determination. m6A is also enriched in other cohorts of mRNAs and can therefore affect their respective cellular processes and pathways. Future work will focus on understanding how the m6A pathway is regulated to achieve control of m6A-containing mRNAs.
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Affiliation(s)
- Shino Murakami
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA.
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31
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XIST loss impairs mammary stem cell differentiation and increases tumorigenicity through Mediator hyperactivation. Cell 2022; 185:2164-2183.e25. [PMID: 35597241 DOI: 10.1016/j.cell.2022.04.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 01/10/2022] [Accepted: 04/27/2022] [Indexed: 12/27/2022]
Abstract
X inactivation (XCI) is triggered by upregulation of XIST, which coats the chromosome in cis, promoting formation of a heterochromatic domain (Xi). XIST role beyond initiation of XCI is only beginning to be elucidated. Here, we demonstrate that XIST loss impairs differentiation of human mammary stem cells (MaSCs) and promotes emergence of highly tumorigenic and metastatic carcinomas. On the Xi, XIST deficiency triggers epigenetic changes and reactivation of genes overlapping Polycomb domains, including Mediator subunit MED14. MED14 overdosage results in increased Mediator levels and hyperactivation of the MaSC enhancer landscape and transcriptional program, making differentiation less favorable. We further demonstrate that loss of XIST and Xi transcriptional instability is common among human breast tumors of poor prognosis. We conclude that XIST is a gatekeeper of human mammary epithelium homeostasis, thus unveiling a paradigm in the control of somatic cell identity with potential consequences for our understanding of gender-specific malignancies.
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32
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Xist-mediated silencing requires additive functions of SPEN and Polycomb together with differentiation-dependent recruitment of SmcHD1. Cell Rep 2022; 39:110830. [PMID: 35584662 DOI: 10.1016/j.celrep.2022.110830] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/17/2022] [Accepted: 04/26/2022] [Indexed: 11/20/2022] Open
Abstract
X chromosome inactivation (XCI) is mediated by the non-coding RNA Xist, which directs chromatin modification and gene silencing in cis. The RNA binding protein SPEN and associated corepressors have a central role in Xist-mediated gene silencing. Other silencing factors, notably the Polycomb system, have been reported to function downstream of SPEN. In recent work, we found that SPEN has an additional role in correct localization of Xist RNA in cis, indicating that its contribution to chromatin-mediated gene silencing needs to be reappraised. Making use of a SPEN separation-of-function mutation, we show that SPEN and Polycomb pathways, in fact, function in parallel to establish gene silencing. We also find that differentiation-dependent recruitment of the chromosomal protein SmcHD1 is required for silencing many X-linked genes. Our results provide important insights into the mechanism of X inactivation and the coordination of chromatin-based gene regulation with cellular differentiation and development.
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33
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Dossin F, Heard E. The Molecular and Nuclear Dynamics of X-Chromosome Inactivation. Cold Spring Harb Perspect Biol 2022; 14:a040196. [PMID: 34312245 PMCID: PMC9121902 DOI: 10.1101/cshperspect.a040196] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In female eutherian mammals, dosage compensation of X-linked gene expression is achieved during development through transcriptional silencing of one of the two X chromosomes. Following X chromosome inactivation (XCI), the inactive X chromosome remains faithfully silenced throughout somatic cell divisions. XCI is dependent on Xist, a long noncoding RNA that coats and silences the X chromosome from which it is transcribed. Xist coating triggers a cascade of chromosome-wide changes occurring at the levels of transcription, chromatin composition, chromosome structure, and spatial organization within the nucleus. XCI has emerged as a paradigm for the study of such crucial nuclear processes and the dissection of their functional interplay. In the past decade, the advent of tools to characterize and perturb these processes have provided an unprecedented understanding into their roles during XCI. The mechanisms orchestrating the initiation of XCI as well as its maintenance are thus being unraveled, although many questions still remain. Here, we introduce key aspects of the XCI process and review the recent discoveries about its molecular basis.
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Affiliation(s)
- François Dossin
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
| | - Edith Heard
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
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34
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Eldesouki S, Samara KA, Qadri R, Obaideen AA, Otour AH, Habbal O, Bm Ahmed S. XIST in Brain Cancer. Clin Chim Acta 2022; 531:283-290. [PMID: 35483442 DOI: 10.1016/j.cca.2022.04.993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/18/2022] [Accepted: 04/21/2022] [Indexed: 11/16/2022]
Abstract
Long non-coding RNAs (lncRNAs) make up the majority of the human genome. They are a group of small RNA molecules that do not code for any proteins but play a primary role in regulating a variety of physiological and pathological processes. X-inactive specific transcript (XIST), one of the first lncRNAs to be discovered, is chiefly responsible for X chromosome inactivation: an evolutionary process of dosage compensation between the sex chromosomes of males and females. Recent studies show that XIST plays a pathophysiological role in the development and prognosis of brain tumors, a heterogeneous group of neoplasms that cause significant morbidity and mortality. In this review, we explore recent advancements in the role of XIST in migration, proliferation, angiogenesis, chemoresistance, and evasion of apoptosis in different types of brain tumors, with particular emphasis on gliomas.
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Affiliation(s)
| | - Kamel A Samara
- College of Medicine, University of Sharjah, Sharjah, UAE
| | - Rama Qadri
- College of Medicine, University of Sharjah, Sharjah, UAE
| | | | - Ahmad H Otour
- College of Medicine, University of Sharjah, Sharjah, UAE
| | - Omar Habbal
- College of Medicine, University of Sharjah, Sharjah, UAE
| | - Samrein Bm Ahmed
- College of Medicine, University of Sharjah, Sharjah, UAE; College of Health and Wellbeing and Life sciences, Department of Biosciences and chemistry, Sheffield Hallam University, UK
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35
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Xist spatially amplifies SHARP/SPEN recruitment to balance chromosome-wide silencing and specificity to the X chromosome. Nat Struct Mol Biol 2022; 29:239-249. [PMID: 35301492 DOI: 10.1038/s41594-022-00739-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 01/28/2022] [Indexed: 11/08/2022]
Abstract
Although thousands of long non-coding RNAs (lncRNAs) are encoded in mammalian genomes, their mechanisms of action are poorly understood, in part because they are often expressed at lower levels than their proposed targets. One such lncRNA is Xist, which mediates chromosome-wide gene silencing on one of the two X chromosomes (X) to achieve gene expression balance between males and females. How a limited number of Xist molecules can mediate robust silencing of a much larger number of target genes while maintaining specificity exclusively to genes on the X within each cell is not well understood. Here, we show that Xist drives non-stoichiometric recruitment of the essential silencing protein SHARP (also known as SPEN) to amplify its abundance across the inactive X, including at regions not directly occupied by Xist. This amplification is achieved through concentration-dependent homotypic assemblies of SHARP on the X and is required for chromosome-wide silencing. Expression of Xist at higher levels leads to increased localization at autosomal regions, demonstrating that low levels of Xist are critical for ensuring its specificity to the X. We show that Xist (through SHARP) acts to suppress production of its own RNA which may act to constrain overall RNA levels and restrict its ability to spread beyond the X. Together, our results demonstrate a spatial amplification mechanism that allows Xist to achieve two essential but countervailing regulatory objectives: chromosome-wide gene silencing and specificity to the X. This suggests a more general mechanism by which other low-abundance lncRNAs could balance specificity to, and robust control of, their regulatory targets.
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36
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Jones AN, Tikhaia E, Mourão A, Sattler M. Structural effects of m6A modification of the Xist A-repeat AUCG tetraloop and its recognition by YTHDC1. Nucleic Acids Res 2022; 50:2350-2362. [PMID: 35166835 PMCID: PMC8887474 DOI: 10.1093/nar/gkac080] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/28/2021] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
The A-repeat region of the lncRNA Xist is critical for X inactivation and harbors several N6-methyladenosine (m6A) modifications. How the m6A modification affects the conformation of the conserved AUCG tetraloop hairpin of the A-repeats and how it can be recognized by the YTHDC1 reader protein is unknown. Here, we report the NMR solution structure of the (m6A)UCG hairpin, which reveals that the m6A base extends 5′ stacking of the A-form helical stem, resembling the unmethylated AUCG tetraloop. A crystal structure of YTHDC1 bound to the (m6A)UCG tetraloop shows that the (m6A)UC nucleotides are recognized by the YTH domain of YTHDC1 in a single-stranded conformation. The m6A base inserts into the aromatic cage and the U and C bases interact with a flanking charged surface region, resembling the recognition of single-stranded m6A RNA ligands. Notably, NMR and fluorescence quenching experiments show that the binding requires local unfolding of the upper stem region of the (m6A)UCG hairpin. Our data show that m6A can be readily accommodated in hairpin loop regions, but recognition by YTH readers requires local unfolding of flanking stem regions. This suggests how m6A modifications may regulate lncRNA function by modulating RNA structure.
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Affiliation(s)
- Alisha N Jones
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747, Garching, Germany
| | - Ekaterina Tikhaia
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747, Garching, Germany
| | - André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747, Garching, Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.,Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747, Garching, Germany
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37
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Gene regulation in time and space during X-chromosome inactivation. Nat Rev Mol Cell Biol 2022; 23:231-249. [PMID: 35013589 DOI: 10.1038/s41580-021-00438-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2021] [Indexed: 12/21/2022]
Abstract
X-chromosome inactivation (XCI) is the epigenetic mechanism that ensures X-linked dosage compensation between cells of females (XX karyotype) and males (XY). XCI is essential for female embryos to survive through development and requires the accurate spatiotemporal regulation of many different factors to achieve remarkable chromosome-wide gene silencing. As a result of XCI, the active and inactive X chromosomes are functionally and structurally different, with the inactive X chromosome undergoing a major conformational reorganization within the nucleus. In this Review, we discuss the multiple layers of genetic and epigenetic regulation that underlie initiation of XCI during development and then maintain it throughout life, in light of the most recent findings in this rapidly advancing field. We discuss exciting new insights into the regulation of X inactive-specific transcript (XIST), the trigger and master regulator of XCI, and into the mechanisms and dynamics that underlie the silencing of nearly all X-linked genes. Finally, given the increasing interest in understanding the impact of chromosome organization on gene regulation, we provide an overview of the factors that are thought to reshape the 3D structure of the inactive X chromosome and of the relevance of such structural changes for XCI establishment and maintenance.
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38
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The lncRNAs at X Chromosome Inactivation Center: Not Just a Matter of Sex Dosage Compensation. Int J Mol Sci 2022; 23:ijms23020611. [PMID: 35054794 PMCID: PMC8775829 DOI: 10.3390/ijms23020611] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 02/06/2023] Open
Abstract
Non-coding RNAs (ncRNAs) constitute the majority of the transcriptome, as the result of pervasive transcription of the mammalian genome. Different RNA species, such as lncRNAs, miRNAs, circRNA, mRNAs, engage in regulatory networks based on their reciprocal interactions, often in a competitive manner, in a way denominated “competing endogenous RNA (ceRNA) networks” (“ceRNET”): miRNAs and other ncRNAs modulate each other, since miRNAs can regulate the expression of lncRNAs, which in turn regulate miRNAs, titrating their availability and thus competing with the binding to other RNA targets. The unbalancing of any network component can derail the entire regulatory circuit acting as a driving force for human diseases, thus assigning “new” functions to “old” molecules. This is the case of XIST, the lncRNA characterized in the early 1990s and well known as the essential molecule for X chromosome inactivation in mammalian females, thus preventing an imbalance of X-linked gene expression between females and males. Currently, literature concerning XIST biology is becoming dominated by miRNA associations and they are also gaining prominence for other lncRNAs produced by the X-inactivation center. This review discusses the available literature to explore possible novel functions related to ceRNA activity of lncRNAs produced by the X-inactivation center, beyond their role in dosage compensation, with prospective implications for emerging gender-biased functions and pathological mechanisms.
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The tandem repeat modules of Xist lncRNA: a swiss army knife for the control of X-chromosome inactivation. Biochem Soc Trans 2021; 49:2549-2560. [PMID: 34882219 PMCID: PMC8786293 DOI: 10.1042/bst20210253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022]
Abstract
X-inactive-specific transcript (Xist) is a long non-coding RNA (lncRNA) essential for X-chromosome inactivation (XCI) in female placental mammals. Thirty years after its discovery, it is still puzzling how this lncRNA triggers major structural and transcriptional changes leading to the stable silencing of an entire chromosome. Recently, a series of studies in mouse cells have uncovered domains of functional specialization within Xist mapping to conserved tandem repeat regions, known as Repeats A-to-F. These functional domains interact with various RNA binding proteins (RBPs) and fold into distinct RNA structures to execute specific tasks in a synergistic and coordinated manner during the inactivation process. This modular organization of Xist is mostly conserved in humans, but recent data point towards differences regarding functional specialization of the tandem repeats between the two species. In this review, we summarize the recent progress on understanding the role of Xist repetitive blocks and their involvement in the molecular mechanisms underlying XCI. We also discuss these findings in the light of the similarities and differences between mouse and human Xist.
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40
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X-chromosome reactivation: a concise review. Biochem Soc Trans 2021; 49:2797-2805. [PMID: 34821360 DOI: 10.1042/bst20210777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 12/14/2022]
Abstract
Mammalian females (XX) silence transcription on one of the two X chromosomes to compensate the expression dosage with males (XY). This process - named X-chromosome inactivation - entails a variety of epigenetic modifications that act synergistically to maintain silencing and make it heritable through cell divisions. Genes along the inactive X chromosome are, indeed, refractory to reactivation. Nonetheless, X-chromosome reactivation can occur alongside with epigenome reprogramming or by perturbing multiple silencing pathways. Here we review the events associated with X-chromosome reactivation during in vivo and in vitro reprogramming and highlight recent efforts in inducing Xi reactivation by molecular perturbations. This provides us with a first understanding of the mechanisms underlying X-chromosome reactivation, which could be tackled for therapeutic purposes.
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41
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Xist nucleates local protein gradients to propagate silencing across the X chromosome. Cell 2021; 184:6174-6192.e32. [PMID: 34813726 PMCID: PMC8671326 DOI: 10.1016/j.cell.2021.10.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/29/2021] [Accepted: 10/11/2021] [Indexed: 02/08/2023]
Abstract
The lncRNA Xist forms ∼50 diffraction-limited foci to transcriptionally silence one X chromosome. How this small number of RNA foci and interacting proteins regulate a much larger number of X-linked genes is unknown. We show that Xist foci are locally confined, contain ∼2 RNA molecules, and nucleate supramolecular complexes (SMACs) that include many copies of the critical silencing protein SPEN. Aggregation and exchange of SMAC proteins generate local protein gradients that regulate broad, proximal chromatin regions. Partitioning of numerous SPEN molecules into SMACs is mediated by their intrinsically disordered regions and essential for transcriptional repression. Polycomb deposition via SMACs induces chromatin compaction and the increase in SMACs density around genes, which propagates silencing across the X chromosome. Our findings introduce a mechanism for functional nuclear compartmentalization whereby crowding of transcriptional and architectural regulators enables the silencing of many target genes by few RNA molecules.
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42
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Robert-Finestra T, Tan BF, Mira-Bontenbal H, Timmers E, Gontan C, Merzouk S, Giaimo BD, Dossin F, van IJcken WFJ, Martens JWM, Borggrefe T, Heard E, Gribnau J. SPEN is required for Xist upregulation during initiation of X chromosome inactivation. Nat Commun 2021; 12:7000. [PMID: 34853312 PMCID: PMC8636516 DOI: 10.1038/s41467-021-27294-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 11/08/2021] [Indexed: 01/11/2023] Open
Abstract
At initiation of X chromosome inactivation (XCI), Xist is monoallelically upregulated from the future inactive X (Xi) chromosome, overcoming repression by its antisense transcript Tsix. Xist recruits various chromatin remodelers, amongst them SPEN, which are involved in silencing of X-linked genes in cis and establishment of the Xi. Here, we show that SPEN plays an important role in initiation of XCI. Spen null female mouse embryonic stem cells (ESCs) are defective in Xist upregulation upon differentiation. We find that Xist-mediated SPEN recruitment to the Xi chromosome happens very early in XCI, and that SPEN-mediated silencing of the Tsix promoter is required for Xist upregulation. Accordingly, failed Xist upregulation in Spen-/- ESCs can be rescued by concomitant removal of Tsix. These findings indicate that SPEN is not only required for the establishment of the Xi, but is also crucial in initiation of the XCI process.
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Affiliation(s)
- Teresa Robert-Finestra
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | - Beatrice F Tan
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | - Hegias Mira-Bontenbal
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | - Erika Timmers
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | - Cristina Gontan
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | - Sarra Merzouk
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands
| | | | - François Dossin
- European Molecular Biology Laboratory, Director's Research, 69117, Heidelberg, Germany
| | - Wilfred F J van IJcken
- Center for Biomics, Erasmus University Medical Center, 3015CN, Rotterdam, The Netherlands
| | - John W M Martens
- Department of Medical Oncology, Erasmus MC Cancer Institute and Cancer Genomics Netherlands, Erasmus University Medical Center, 3015CN, Rotterdam, The Netherlands
| | - Tilman Borggrefe
- Institute of Biochemistry, University of Giessen, 35392, Giessen, Germany
| | - Edith Heard
- European Molecular Biology Laboratory, Director's Research, 69117, Heidelberg, Germany
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus University Medical Center, Oncode Institute, 3015GD, Rotterdam, The Netherlands.
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43
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Cayir A. RNA modifications as emerging therapeutic targets. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 13:e1702. [PMID: 34816607 DOI: 10.1002/wrna.1702] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 12/11/2022]
Abstract
The field of epitranscriptome, posttranscriptional modifications to RNAs, is still growing up and has presented substantial evidences for the role of RNA modifications in diseases. In terms of new drug development, RNA modifications have a great promise for therapy. For example, more than 170 type of modifications exist in various types of RNAs. Regulatory genes and their roles in critical biological process have been identified and they are associated with several diseases. Current data, for example, identification of inhibitors targeting RNA modifications regulatory genes, strongly support the idea that RNA modifications have potential as emerging therapeutic targets. Therefore, in this review, RNA modifications and regulatory genes were comprehensively documented in terms of drug development by summarizing the findings from previous studies. It was discussed how RNA modifications or regulatory genes can be targeted by altering molecular mechanisms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Akin Cayir
- Vocational Health College, Canakkale Onsekiz Mart University, Canakkale, Turkey.,Akershus Universitetssykehus, Medical Department, Lørenskog, Norway
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44
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Trotman JB, Braceros KCA, Cherney RE, Murvin MM, Calabrese JM. The control of polycomb repressive complexes by long noncoding RNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1657. [PMID: 33861025 PMCID: PMC8500928 DOI: 10.1002/wrna.1657] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/12/2021] [Accepted: 03/19/2021] [Indexed: 02/06/2023]
Abstract
The polycomb repressive complexes 1 and 2 (PRCs; PRC1 and PRC2) are conserved histone-modifying enzymes that often function cooperatively to repress gene expression. The PRCs are regulated by long noncoding RNAs (lncRNAs) in complex ways. On the one hand, specific lncRNAs cause the PRCs to engage with chromatin and repress gene expression over genomic regions that can span megabases. On the other hand, the PRCs bind RNA with seemingly little sequence specificity, and at least in the case of PRC2, direct RNA-binding has the effect of inhibiting the enzyme. Thus, some RNAs appear to promote PRC activity, while others may inhibit it. The reasons behind this apparent dichotomy are unclear. The most potent PRC-activating lncRNAs associate with chromatin and are predominantly unspliced or harbor unusually long exons. Emerging data imply that these lncRNAs promote PRC activity through internal RNA sequence elements that arise and disappear rapidly in evolutionary time. These sequence elements may function by interacting with common subsets of RNA-binding proteins that recruit or stabilize PRCs on chromatin. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Jackson B. Trotman
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Keean C. A. Braceros
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Mechanistic, Interdisciplinary Studies of Biological Systems, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rachel E. Cherney
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - McKenzie M. Murvin
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - J. Mauro Calabrese
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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45
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Appel LM, Franke V, Bruno M, Grishkovskaya I, Kasiliauskaite A, Kaufmann T, Schoeberl UE, Puchinger MG, Kostrhon S, Ebenwaldner C, Sebesta M, Beltzung E, Mechtler K, Lin G, Vlasova A, Leeb M, Pavri R, Stark A, Akalin A, Stefl R, Bernecky C, Djinovic-Carugo K, Slade D. PHF3 regulates neuronal gene expression through the Pol II CTD reader domain SPOC. Nat Commun 2021; 12:6078. [PMID: 34667177 PMCID: PMC8526623 DOI: 10.1038/s41467-021-26360-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 09/29/2021] [Indexed: 12/16/2022] Open
Abstract
The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) is a regulatory hub for transcription and RNA processing. Here, we identify PHD-finger protein 3 (PHF3) as a regulator of transcription and mRNA stability that docks onto Pol II CTD through its SPOC domain. We characterize SPOC as a CTD reader domain that preferentially binds two phosphorylated Serine-2 marks in adjacent CTD repeats. PHF3 drives liquid-liquid phase separation of phosphorylated Pol II, colocalizes with Pol II clusters and tracks with Pol II across the length of genes. PHF3 knock-out or SPOC deletion in human cells results in increased Pol II stalling, reduced elongation rate and an increase in mRNA stability, with marked derepression of neuronal genes. Key neuronal genes are aberrantly expressed in Phf3 knock-out mouse embryonic stem cells, resulting in impaired neuronal differentiation. Our data suggest that PHF3 acts as a prominent effector of neuronal gene regulation by bridging transcription with mRNA decay.
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Affiliation(s)
- Lisa-Marie Appel
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Vedran Franke
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Berlin, Germany
| | - Melania Bruno
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Aiste Kasiliauskaite
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tanja Kaufmann
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Ursula E Schoeberl
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin G Puchinger
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Sebastian Kostrhon
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Carmen Ebenwaldner
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Marek Sebesta
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Etienne Beltzung
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Gen Lin
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Anna Vlasova
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Martin Leeb
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, Vienna Biocenter (VBC), Vienna, Austria
| | - Altuna Akalin
- The Berlin Institute for Medical Systems Biology, Max Delbrück Center, Berlin, Germany
| | - Richard Stefl
- CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Carrie Bernecky
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, Klosterneuburg, Austria
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Dea Slade
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria.
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
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46
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Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
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Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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47
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Exploring chromatin structural roles of non-coding RNAs at imprinted domains. Biochem Soc Trans 2021; 49:1867-1879. [PMID: 34338292 PMCID: PMC8421051 DOI: 10.1042/bst20210758] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 12/11/2022]
Abstract
Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.
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48
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Szanto A, Aguilar R, Kesner B, Blum R, Wang D, Cifuentes-Rojas C, Del Rosario BC, Kis-Toth K, Lee JT. A disproportionate impact of G9a methyltransferase deficiency on the X chromosome. Genes Dev 2021; 35:1035-1054. [PMID: 34168040 PMCID: PMC8247598 DOI: 10.1101/gad.337592.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/27/2021] [Indexed: 01/05/2023]
Abstract
In this study from Szanto et al., the authors investigated the role of G9a, a histone methyltransferase responsible for the dimethylation of histone H3 at lysine 9 (H3K9me2) that plays key roles in transcriptional silencing of developmentally regulated genes, in X-chromosome inactivation (XCI). They found a female-specific function of G9a and demonstrate that deleting G9a has a disproportionate impact on the X chromosome relative to the rest of the genome, and show RNA tethers G9a for allele-specific targeting of the H3K9me2 modification and the G9a–RNA interaction is essential for XCI. G9a is a histone methyltransferase responsible for the dimethylation of histone H3 at lysine 9 (H3K9me2). G9a plays key roles in transcriptional silencing of developmentally regulated genes, but its role in X-chromosome inactivation (XCI) has been under debate. Here, we uncover a female-specific function of G9a and demonstrate that deleting G9a has a disproportionate impact on the X chromosome relative to the rest of the genome. G9a deficiency causes a failure of XCI and female-specific hypersensitivity to drug inhibition of H3K9me2. We show that G9a interacts with Tsix and Xist RNAs, and that competitive inhibition of the G9a-RNA interaction recapitulates the XCI defect. During XCI, Xist recruits G9a to silence X-linked genes on the future inactive X. In parallel on the future Xa, Tsix recruits G9a to silence Xist in cis. Thus, RNA tethers G9a for allele-specific targeting of the H3K9me2 modification and the G9a-RNA interaction is essential for XCI.
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Affiliation(s)
- Attila Szanto
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Rodrigo Aguilar
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Barry Kesner
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Roy Blum
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Danni Wang
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Catherine Cifuentes-Rojas
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Brian C Del Rosario
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Katalin Kis-Toth
- Department of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, Massachusetts 02115, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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49
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Rodermund L, Coker H, Oldenkamp R, Wei G, Bowness J, Rajkumar B, Nesterova T, Susano Pinto DM, Schermelleh L, Brockdorff N. Time-resolved structured illumination microscopy reveals key principles of Xist RNA spreading. Science 2021; 372:372/6547/eabe7500. [PMID: 34112668 DOI: 10.1126/science.abe7500] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 05/07/2021] [Indexed: 01/23/2023]
Abstract
X-inactive specific transcript (Xist) RNA directs the process of X chromosome inactivation in mammals by spreading in cis along the chromosome from which it is transcribed and recruiting chromatin modifiers to silence gene transcription. To elucidate mechanisms of Xist RNA cis-confinement, we established a sequential dual-color labeling, super-resolution imaging approach to trace individual Xist RNA molecules over time, which enabled us to define fundamental parameters of spreading. We demonstrate a feedback mechanism linking Xist RNA synthesis and degradation and an unexpected physical coupling between preceding and newly synthesized Xist RNA molecules. Additionally, we find that the protein SPEN, a key factor for Xist-mediated gene silencing, has a distinct function in Xist RNA localization, stability, and coupling behaviors. Our results provide insights toward understanding the distinct dynamic properties of Xist RNA.
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Affiliation(s)
- Lisa Rodermund
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Heather Coker
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Roel Oldenkamp
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Guifeng Wei
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Joseph Bowness
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Bramman Rajkumar
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Tatyana Nesterova
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | | | - Neil Brockdorff
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
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50
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Wei G, Almeida M, Pintacuda G, Coker H, Bowness JS, Ule J, Brockdorff N. Acute depletion of METTL3 implicates N 6-methyladenosine in alternative intron/exon inclusion in the nascent transcriptome. Genome Res 2021; 31:1395-1408. [PMID: 34131006 PMCID: PMC8327914 DOI: 10.1101/gr.271635.120] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 06/10/2021] [Indexed: 01/15/2023]
Abstract
RNA N 6-methyladenosine (m6A) modification plays important roles in multiple aspects of RNA regulation. m6A is installed cotranscriptionally by the METTL3/14 complex, but its direct roles in RNA processing remain unclear. Here, we investigate the presence of m6A in nascent RNA of mouse embryonic stem cells. We find that around 10% of m6A peaks are located in alternative introns/exons, often close to 5' splice sites. m6A peaks significantly overlap with RBM15 RNA binding sites and the histone modification H3K36me3. Acute depletion of METTL3 disrupts inclusion of alternative introns/exons in the nascent transcriptome, particularly at 5' splice sites that are proximal to m6A peaks. For terminal or variable-length exons, m6A peaks are generally located on or immediately downstream from a 5' splice site that is suppressed in the presence of m6A and upstream of a 5' splice site that is promoted in the presence of m6A. Genes with the most immediate effects on splicing include several components of the m6A pathway, suggesting an autoregulatory function. Collectively, our findings demonstrate crosstalk between the m6A machinery and the regulation of RNA splicing.
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Affiliation(s)
- Guifeng Wei
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Mafalda Almeida
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Greta Pintacuda
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Heather Coker
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Joseph S Bowness
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jernej Ule
- The Francis Crick Institute, London NW1 1AT, United Kingdom.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Neil Brockdorff
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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