1
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Nickerson JA, Momen-Heravi F. Long non-coding RNAs: roles in cellular stress responses and epigenetic mechanisms regulating chromatin. Nucleus 2024; 15:2350180. [PMID: 38773934 PMCID: PMC11123517 DOI: 10.1080/19491034.2024.2350180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/22/2024] [Indexed: 05/24/2024] Open
Abstract
Most of the genome is transcribed into RNA but only 2% of the sequence codes for proteins. Non-coding RNA transcripts include a very large number of long noncoding RNAs (lncRNAs). A growing number of identified lncRNAs operate in cellular stress responses, for example in response to hypoxia, genotoxic stress, and oxidative stress. Additionally, lncRNA plays important roles in epigenetic mechanisms operating at chromatin and in maintaining chromatin architecture. Here, we address three lncRNA topics that have had significant recent advances. The first is an emerging role for many lncRNAs in cellular stress responses. The second is the development of high throughput screening assays to develop causal relationships between lncRNAs across the genome with cellular functions. Finally, we turn to recent advances in understanding the role of lncRNAs in regulating chromatin architecture and epigenetics, advances that build on some of the earliest work linking RNA to chromatin architecture.
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Affiliation(s)
- Jeffrey A Nickerson
- Division of Genes & Development, Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Fatemeh Momen-Heravi
- College of Dental Medicine, Columbia University Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
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2
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Thayer M, Heskett MB, Smith LG, Spellman PT, Yates PA. ASAR lncRNAs control DNA replication timing through interactions with multiple hnRNP/RNA binding proteins. eLife 2024; 13:RP95898. [PMID: 38896448 PMCID: PMC11186638 DOI: 10.7554/elife.95898] [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: 06/21/2024] Open
Abstract
ASARs are a family of very-long noncoding RNAs that control replication timing on individual human autosomes, and are essential for chromosome stability. The eight known ASAR lncRNAs remain closely associated with their parent chromosomes. Analysis of RNA-protein interaction data (from ENCODE) revealed numerous RBPs with significant interactions with multiple ASAR lncRNAs, with several hnRNPs as abundant interactors. An ~7 kb domain within the ASAR6-141 lncRNA shows a striking density of RBP interaction sites. Genetic deletion and ectopic integration assays indicate that this ~7 kb RNA binding protein domain contains functional sequences for controlling replication timing of entire chromosomes in cis. shRNA-mediated depletion of 10 different RNA binding proteins, including HNRNPA1, HNRNPC, HNRNPL, HNRNPM, HNRNPU, or HNRNPUL1, results in dissociation of ASAR lncRNAs from their chromosome territories, and disrupts the synchronous replication that occurs on all autosome pairs, recapitulating the effect of individual ASAR knockouts on a genome-wide scale. Our results further demonstrate the role that ASARs play during the temporal order of genome-wide replication, and we propose that ASARs function as essential RNA scaffolds for the assembly of hnRNP complexes that help maintain the structural integrity of each mammalian chromosome.
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Affiliation(s)
- Mathew Thayer
- Department of Chemical Physiology and Biochemistry,Oregon Health & Science UniversityPortlandUnited States
| | - Michael B Heskett
- Department of Molecular and Medical Genetics, Oregon Health & Science UniversityPortlandUnited States
- Stanford Cancer InstituteStanfordUnited States
| | - Leslie G Smith
- Department of Chemical Physiology and Biochemistry,Oregon Health & Science UniversityPortlandUnited States
| | - Paul T Spellman
- Department of Molecular and Medical Genetics, Oregon Health & Science UniversityPortlandUnited States
- Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health & Science UniversityPortlandUnited States
| | - Phillip A Yates
- Department of Chemical Physiology and Biochemistry,Oregon Health & Science UniversityPortlandUnited States
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3
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Daugird TA, Shi Y, Holland KL, Rostamian H, Liu Z, Lavis LD, Rodriguez J, Strahl BD, Legant WR. Correlative single molecule lattice light sheet imaging reveals the dynamic relationship between nucleosomes and the local chromatin environment. Nat Commun 2024; 15:4178. [PMID: 38755200 PMCID: PMC11099156 DOI: 10.1038/s41467-024-48562-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/03/2024] [Indexed: 05/18/2024] Open
Abstract
In the nucleus, biological processes are driven by proteins that diffuse through and bind to a meshwork of nucleic acid polymers. To better understand this interplay, we present an imaging platform to simultaneously visualize single protein dynamics together with the local chromatin environment in live cells. Together with super-resolution imaging, new fluorescent probes, and biophysical modeling, we demonstrate that nucleosomes display differential diffusion and packing arrangements as chromatin density increases whereas the viscoelastic properties and accessibility of the interchromatin space remain constant. Perturbing nuclear functions impacts nucleosome diffusive properties in a manner that is dependent both on local chromatin density and on relative location within the nucleus. Our results support a model wherein transcription locally stabilizes nucleosomes while simultaneously allowing for the free exchange of nuclear proteins. Additionally, they reveal that nuclear heterogeneity arises from both active and passive processes and highlight the need to account for different organizational principles when modeling different chromatin environments.
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Affiliation(s)
- Timothy A Daugird
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yu Shi
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, North Carolina State University, Chapel Hill, NC, USA
| | - Katie L Holland
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Hosein Rostamian
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhe Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Joseph Rodriguez
- National Institute of Environmental Health Sciences, Durham, NC, 27709, USA
| | - Brian D Strahl
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Wesley R Legant
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, North Carolina State University, Chapel Hill, NC, USA.
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4
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Agrawal S, Buyan A, Severin J, Koido M, Alam T, Abugessaisa I, Chang HY, Dostie J, Itoh M, Kere J, Kondo N, Li Y, Makeev VJ, Mendez M, Okazaki Y, Ramilowski JA, Sigorskikh AI, Strug LJ, Yagi K, Yasuzawa K, Yip CW, Hon CC, Hoffman MM, Terao C, Kulakovskiy IV, Kasukawa T, Shin JW, Carninci P, de Hoon MJL. Annotation of nuclear lncRNAs based on chromatin interactions. PLoS One 2024; 19:e0295971. [PMID: 38709794 PMCID: PMC11073715 DOI: 10.1371/journal.pone.0295971] [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: 06/19/2023] [Accepted: 12/02/2023] [Indexed: 05/08/2024] Open
Abstract
The human genome is pervasively transcribed and produces a wide variety of long non-coding RNAs (lncRNAs), constituting the majority of transcripts across human cell types. Some specific nuclear lncRNAs have been shown to be important regulatory components acting locally. As RNA-chromatin interaction and Hi-C chromatin conformation data showed that chromatin interactions of nuclear lncRNAs are determined by the local chromatin 3D conformation, we used Hi-C data to identify potential target genes of lncRNAs. RNA-protein interaction data suggested that nuclear lncRNAs act as scaffolds to recruit regulatory proteins to target promoters and enhancers. Nuclear lncRNAs may therefore play a role in directing regulatory factors to locations spatially close to the lncRNA gene. We provide the analysis results through an interactive visualization web portal at https://fantom.gsc.riken.jp/zenbu/reports/#F6_3D_lncRNA.
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Affiliation(s)
- Saumya Agrawal
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Andrey Buyan
- Autosome.org, Russia
- FANTOM Consortium, Dolgoprudny, Russia
| | - Jessica Severin
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Masaru Koido
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tanvir Alam
- College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar
| | | | - Howard Y. Chang
- Center for Personal Dynamic Regulome, Stanford University, Stanford, California, United States of America
| | - Josée Dostie
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
| | - Masayoshi Itoh
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- RIKEN Preventive Medicine and Diagnosis Innovation Program, Wako, Japan
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- Stem Cells and Metabolism Research Program, University of Helsinki and Folkhälsan Research Center, Helsinki, Finland
| | - Naoto Kondo
- RIKEN Center for Life Science Technologies, Yokohama, Japan
| | - Yunjing Li
- Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | | | - Mickaël Mendez
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
| | - Yasushi Okazaki
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Jordan A. Ramilowski
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
| | | | - Lisa J. Strug
- Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
- Department of Statistical Sciences, University of Toronto, Ontario, Canada
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ken Yagi
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Kayoko Yasuzawa
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Chi Wai Yip
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Chung Chau Hon
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Michael M. Hoffman
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Vector Institute, Toronto, Ontario, Canada
| | - Chikashi Terao
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | | | - Takeya Kasukawa
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Jay W. Shin
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Piero Carninci
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Human Technopole, Milan, Italy
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5
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Han X, Xing L, Hong Y, Zhang X, Hao B, Lu JY, Huang M, Wang Z, Ma S, Zhan G, Li T, Hao X, Tao Y, Li G, Zhou S, Zheng Z, Shao W, Zeng Y, Ma D, Zhang W, Xie Z, Deng H, Yan J, Deng W, Shen X. Nuclear RNA homeostasis promotes systems-level coordination of cell fate and senescence. Cell Stem Cell 2024; 31:694-716.e11. [PMID: 38631356 DOI: 10.1016/j.stem.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/01/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Understanding cellular coordination remains a challenge despite knowledge of individual pathways. The RNA exosome, targeting a wide range of RNA substrates, is often downregulated in cellular senescence. Utilizing an auxin-inducible system, we observed that RNA exosome depletion in embryonic stem cells significantly affects the transcriptome and proteome, causing pluripotency loss and pre-senescence onset. Mechanistically, exosome depletion triggers acute nuclear RNA aggregation, disrupting nuclear RNA-protein equilibrium. This disturbance limits nuclear protein availability and hinders polymerase initiation and engagement, reducing gene transcription. Concurrently, it promptly disrupts nucleolar transcription, ribosomal processes, and nuclear exporting, resulting in a translational shutdown. Prolonged exosome depletion induces nuclear structural changes resembling senescent cells, including aberrant chromatin compaction, chromocenter disassembly, and intensified heterochromatic foci. These effects suggest that the dynamic turnover of nuclear RNA orchestrates crosstalk between essential processes to optimize cellular function. Disruptions in nuclear RNA homeostasis result in systemic functional decline, altering the cell state and promoting senescence.
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Affiliation(s)
- Xue Han
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Linqing Xing
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yantao Hong
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xuechun Zhang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Bo Hao
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - J Yuyang Lu
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Mengyuan Huang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Shaoqian Ma
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Ge Zhan
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Tong Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaowen Hao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yibing Tao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Guanwen Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Shuqin Zhou
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zheng Zheng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Wen Shao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yitian Zeng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Dacheng Ma
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Wenhao Zhang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhen Xie
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiangwei Yan
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xiaohua Shen
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China; SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China.
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6
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Ferrer J, Dimitrova N. Transcription regulation by long non-coding RNAs: mechanisms and disease relevance. Nat Rev Mol Cell Biol 2024; 25:396-415. [PMID: 38242953 PMCID: PMC11045326 DOI: 10.1038/s41580-023-00694-9] [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] [Accepted: 12/11/2023] [Indexed: 01/21/2024]
Abstract
Long non-coding RNAs (lncRNAs) outnumber protein-coding transcripts, but their functions remain largely unknown. In this Review, we discuss the emerging roles of lncRNAs in the control of gene transcription. Some of the best characterized lncRNAs have essential transcription cis-regulatory functions that cannot be easily accomplished by DNA-interacting transcription factors, such as XIST, which controls X-chromosome inactivation, or imprinted lncRNAs that direct allele-specific repression. A growing number of lncRNA transcription units, including CHASERR, PVT1 and HASTER (also known as HNF1A-AS1) act as transcription-stabilizing elements that fine-tune the activity of dosage-sensitive genes that encode transcription factors. Genetic experiments have shown that defects in such transcription stabilizers often cause severe phenotypes. Other lncRNAs, such as lincRNA-p21 (also known as Trp53cor1) and Maenli (Gm29348) contribute to local activation of gene transcription, whereas distinct lncRNAs influence gene transcription in trans. We discuss findings of lncRNAs that elicit a function through either activation of their transcription, transcript elongation and processing or the lncRNA molecule itself. We also discuss emerging evidence of lncRNA involvement in human diseases, and their potential as therapeutic targets.
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Affiliation(s)
- Jorge Ferrer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Nadya Dimitrova
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.
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7
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Lawrence J, Hall L. Exceptionally long-lived nuclear RNAs. Science 2024; 384:31-32. [PMID: 38574156 DOI: 10.1126/science.ado5751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
RNA labeled in young mice is detected 2 years later in adult mouse brains.
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Affiliation(s)
- Jeanne Lawrence
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Lisa Hall
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA
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8
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Healy E, Zhang Q, Gail EH, Agius SC, Sun G, Bullen M, Pandey V, Das PP, Polo JM, Davidovich C. The apparent loss of PRC2 chromatin occupancy as an artifact of RNA depletion. Cell Rep 2024; 43:113858. [PMID: 38416645 DOI: 10.1016/j.celrep.2024.113858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/08/2023] [Accepted: 02/08/2024] [Indexed: 03/01/2024] Open
Abstract
RNA has been implicated in the recruitment of chromatin modifiers, and previous studies have provided evidence in favor and against this idea. RNase treatment of chromatin is commonly used to study RNA-mediated regulation of chromatin modifiers, but the limitations of this approach remain unclear. RNase A treatment during chromatin immunoprecipitation (ChIP) reduces chromatin occupancy of the H3K27me3 methyltransferase Polycomb repressive complex 2 (PRC2). This led to suggestions of an "RNA bridge" between PRC2 and chromatin. Here, we show that RNase A treatment during ChIP causes the apparent loss of all facultative heterochromatin, including both PRC2 and H3K27me3 genome-wide. We track this observation to a gain of DNA from non-targeted chromatin, sequenced at the expense of DNA from facultative heterochromatin, which reduces ChIP signals. Our results emphasize substantial limitations in using RNase A treatment for mapping RNA-dependent chromatin occupancy and invalidate conclusions that were previously established for PRC2 based on this assay.
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Affiliation(s)
- Evan Healy
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Qi Zhang
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia; South Australian immunoGENomics Cancer Institute (SAiGENCI), Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia; EMBL-Australia at SAiGENCI, Adelaide, SA, Australia
| | - Emma H Gail
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Samuel C Agius
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Guizhi Sun
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Wellington Road, Clayton, VIC 3800, Australia
| | - Michael Bullen
- Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Varun Pandey
- Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Partha Pratim Das
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Wellington Road, Clayton, VIC 3800, Australia; Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Jose M Polo
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Wellington Road, Clayton, VIC 3800, Australia; Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia; Adelaide Centre for Epigenetics and South Australian immunoGENomics Cancer Institute, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia; EMBL-Australia, Clayton, VIC, Australia.
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9
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Gupta K, Czerminski JT, Lawrence JB. Trisomy silencing by XIST: translational prospects and challenges. Hum Genet 2024:10.1007/s00439-024-02651-8. [PMID: 38459355 DOI: 10.1007/s00439-024-02651-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/25/2024] [Indexed: 03/10/2024]
Abstract
XIST RNA is heavily studied for its role in fundamental epigenetics and X-chromosome inactivation; however, the translational potential of this singular RNA has been much less explored. This article combines elements of a review on XIST biology with our perspective on the translational prospects and challenges of XIST transgenics. We first briefly review aspects of XIST RNA basic biology that are key to its translational relevance, and then discuss recent efforts to develop translational utility of XIST for chromosome dosage disorders, particularly Down syndrome (DS). Remarkably, it was shown in vitro that expression of an XIST transgene inserted into one chromosome 21 can comprehensively silence that chromosome and "dosage compensate" Trisomy 21, the cause of DS. Here we summarize recent findings and discuss potential paths whereby ability to induce "trisomy silencing" can advance translational research for new therapeutic strategies. Despite its common nature, the underlying biology for various aspects of DS, including cell types and pathways impacted (and when), is poorly understood. Recent studies show that an inducible iPSC system to dosage-correct chromosome 21 can provide a powerful approach to unravel the cells and pathways directly impacted, and the developmental timing, information key to design pharmacotherapeutics. In addition, we discuss prospects of a more far-reaching and challenging possibility that XIST itself could be developed into a therapeutic agent, for targeted cellular "chromosome therapy". A few rare case studies of imbalanced X;autosome translocations indicate that natural XIST can rescue an otherwise lethal trisomy. The potential efficacy of XIST transgenes later in development faces substantial biological and technical challenges, although recent findings are encouraging, and technology is rapidly evolving. Hence, it is compelling to consider the transformative possibility that XIST-mediated chromosome therapy may ultimately be developed, for specific pathologies seen in DS, or other duplication disorders.
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Affiliation(s)
- Khusali Gupta
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Jan T Czerminski
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
- Medical Scientist Training Program, 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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10
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Kletzien OA, Wuttke DS, Batey RT. The RNA-Binding Domain of hnRNP U Extends beyond the RGG/RG Motifs. Biochemistry 2024. [PMID: 38329035 DOI: 10.1021/acs.biochem.3c00510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Heterogeneous nuclear ribonucleoprotein U (hnRNP U) is a ubiquitously expressed protein that regulates chromatin architecture through its interactions with numerous DNA, protein, and RNA partners. The RNA-binding domain (RBD) of hnRNP U was previously mapped to an RGG/RG motif within its disordered C-terminal region, but little is understood about its binding mode and potential for selective RNA recognition. Analysis of publicly available hnRNP U enhanced UV cross-linking and immunoprecipitation (eCLIP) data identified high-confidence binding sites within human RNAs. We synthesized a set of diverse RNAs encompassing 11 of these identified cross-link sites for biochemical characterization using a combination of fluorescence anisotropy and electrophoretic mobility shift assays. These in vitro binding experiments with a rationally designed set of RNAs and hnRNP U domains revealed that the RGG/RG motif is a small part of a more expansive RBD that encompasses most of the disordered C-terminal region. This RBD contains a second, previously experimentally uncharacterized RGG/RG motif with RNA-binding properties comparable to those of the canonical RGG/RG motif. These RGG/RG motifs serve redundant functions, with neither serving as the primary RBD. While in isolation, each RGG/RG motif has modest affinity for RNA, together they significantly enhance the association of hnRNP U with RNA, enabling the binding of most of the designed RNA set with low to midnanomolar binding affinities. Identification and characterization of the complete hnRNP U RBD highlight the perils of a reductionist approach to defining biochemical activities in this system and pave the way for a detailed investigation of its RNA-binding specificity.
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Affiliation(s)
- Otto A Kletzien
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80309-0596, United States
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80309-0596, United States
| | - Robert T Batey
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80309-0596, United States
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11
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Miglierina E, Ordanoska D, Le Noir S, Laffleur B. RNA processing mechanisms contribute to genome organization and stability in B cells. Oncogene 2024; 43:615-623. [PMID: 38287115 PMCID: PMC10890934 DOI: 10.1038/s41388-024-02952-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 01/31/2024]
Abstract
RNA processing includes post-transcriptional mechanisms controlling RNA quality and quantity to ensure cellular homeostasis. Noncoding (nc) RNAs that are regulated by these dynamic processes may themselves fulfill effector and/or regulatory functions, and recent studies demonstrated the critical role of RNAs in organizing both chromatin and genome architectures. Furthermore, RNAs can threaten genome integrity when accumulating as DNA:RNA hybrids, but could also facilitate DNA repair depending on the molecular context. Therefore, by qualitatively and quantitatively fine-tuning RNAs, RNA processing contributes directly or indirectly to chromatin states, genome organization, and genome stability. B lymphocytes represent a unique model to study these interconnected mechanisms as they express ncRNAs transcribed from key specific sequences before undergoing physiological genetic remodeling processes, including V(D)J recombination, somatic hypermutation, and class switch recombination. RNA processing actors ensure the regulation and degradation of these ncRNAs for efficient DNA repair and immunoglobulin gene remodeling while failure leads to B cell development alterations, aberrant DNA repair, and pathological translocations. This review highlights how RNA processing mechanisms contribute to genome architecture and stability, with emphasis on their critical roles during B cell development, enabling physiological DNA remodeling while preventing lymphomagenesis.
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Affiliation(s)
- Emma Miglierina
- University of Rennes, Inserm, EFS Bretagne, CHU Rennes, UMR, 1236, Rennes, France
| | - Delfina Ordanoska
- University of Rennes, Inserm, EFS Bretagne, CHU Rennes, UMR, 1236, Rennes, France
| | - Sandrine Le Noir
- UMR CNRS 7276, Inserm 1262, Université de Limoges: Contrôle de la Réponse Immune B et des Lymphoproliférations, Team 2, B-NATION: B cell Nuclear Architecture, Immunoglobulin genes and Oncogenes, Limoges, France
| | - Brice Laffleur
- University of Rennes, Inserm, EFS Bretagne, CHU Rennes, UMR, 1236, Rennes, France.
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12
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Hall LL, Creamer KM, Byron M, Lawrence JB. Differences in Alu vs L1-rich chromosome bands underpin architectural reorganization of the inactive-X chromosome and SAHFs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574742. [PMID: 38260534 PMCID: PMC10802495 DOI: 10.1101/2024.01.09.574742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The linear DNA sequence of mammalian chromosomes is organized in large blocks of DNA with similar sequence properties, producing a pattern of dark and light staining bands on mitotic chromosomes. Cytogenetic banding is essentially invariant between people and cell-types and thus may be assumed unrelated to genome regulation. We investigate whether large blocks of Alu-rich R-bands and L1-rich G-bands provide a framework upon which functional genome architecture is built. We examine two models of large-scale chromatin condensation: X-chromosome inactivation and formation of senescence-associated heterochromatin foci (SAHFs). XIST RNA triggers gene silencing but also formation of the condensed Barr Body (BB), thought to reflect cumulative gene silencing. However, we find Alu-rich regions are depleted from the L1-rich BB, supporting it is a dense core but not the entire chromosome. Alu-rich bands are also gene-rich, affirming our earlier findings that genes localize at the outer periphery of the BB. SAHFs similarly form within each territory by coalescence of syntenic L1 regions depleted for highly Alu-rich DNA. Analysis of senescent cell Hi-C data also shows large contiguous blocks of G-band and R-band DNA remodel as a segmental unit. Entire dark-bands gain distal intrachromosomal interactions as L1-rich regions form the SAHF. Most striking is that sharp Alu peaks within R-bands resist these changes in condensation. We further show that Chr19, which is exceptionally Alu rich, fails to form a SAHF. Collective results show regulation of genome architecture corresponding to large blocks of DNA and demonstrate resistance of segments with high Alu to chromosome condensation.
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Affiliation(s)
- Lisa L. Hall
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Kevin M. Creamer
- 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
| | - Jeanne B. Lawrence
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
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13
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Bihani A, Avvaru AK, Mishra RK. Biochemical Deconstruction and Reconstruction of Nuclear Matrix Reveals the Layers of Nuclear Organization. Mol Cell Proteomics 2023; 22:100671. [PMID: 37863319 PMCID: PMC10687341 DOI: 10.1016/j.mcpro.2023.100671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/11/2023] [Accepted: 10/15/2023] [Indexed: 10/22/2023] Open
Abstract
Nuclear matrix (NuMat) is the fraction of the eukaryotic nucleus insoluble to detergents and high-salt extractions that manifests as a pan-nuclear fiber-granule network. NuMat consists of ribonucleoprotein complexes, members of crucial nuclear functional modules, and DNA fragments. Although NuMat captures the organization of nonchromatin nuclear space, very little is known about components organization within NuMat. To understand the organization of NuMat components, we subfractionated it with increasing concentrations of the chaotrope guanidinium hydrochloride (GdnHCl) and analyzed the proteomic makeup of the fractions. We observe that the solubilization of proteins at different concentrations of GdnHCl is finite and independent of the broad biophysical properties of the protein sequences. Looking at the extraction pattern of the nuclear envelope and nuclear pore complex, we surmise that this fractionation represents easily solubilized/loosely bound and difficultly solubilized/tightly bound components of NuMat. Microscopic analyses of the localization of key NuMat proteins across sequential GdnHCl extractions of in situ NuMat further elaborate on the divergent extraction patterns. Furthermore, we solubilized NuMat in 8M GdnHCl and upon removal of GdnHCl through dialysis, en masse renaturation leads to RNA-dependent self-assembly of fibrous structures. The major proteome component of the self-assembled fibers comes from the difficultly solubilized, tightly bound component. This fractionation of the NuMat reveals different organizational levels within it which may reflect the structural and functional organization of nuclear architecture.
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Affiliation(s)
- Ashish Bihani
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India.
| | - Akshay K Avvaru
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India; Tata Institute for Genetics and Society (TIGS), Bengaluru, India.
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14
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Daugird TA, Shi Y, Holland KL, Rostamian H, Liu Z, Lavis LD, Rodriguez J, Strahl BD, Legant WR. Correlative single molecule lattice light sheet imaging reveals the dynamic relationship between nucleosomes and the local chromatin environment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566470. [PMID: 38014222 PMCID: PMC10680651 DOI: 10.1101/2023.11.09.566470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
In the nucleus, biological processes are driven by proteins that diffuse through and bind to a meshwork of nucleic acid polymers. To better understand this interplay, we developed an imaging platform to simultaneously visualize single protein dynamics together with the local chromatin environment in live cells. Together with super-resolution imaging, new fluorescent probes, and biophysical modeling, we demonstrated that nucleosomes display differential diffusion and packing arrangements as chromatin density increases whereas the viscoelastic properties and accessibility of the interchromatin space remain constant. Perturbing nuclear functions impacted nucleosome diffusive properties in a manner that was dependent on local chromatin density and supportive of a model wherein transcription locally stabilizes nucleosomes while simultaneously allowing for the free exchange of nuclear proteins. Our results reveal that nuclear heterogeneity arises from both active and passive process and highlights the need to account for different organizational principals when modeling different chromatin environments.
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15
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Cherney RE, Eberhard QE, Giri G, Mills CA, Porrello A, Zhang Z, White D, Trotman JB, Herring LE, Dominguez D, Calabrese JM. SAFB associates with nascent RNAs and can promote gene expression in mouse embryonic stem cells. RNA (NEW YORK, N.Y.) 2023; 29:1535-1556. [PMID: 37468167 PMCID: PMC10578485 DOI: 10.1261/rna.079569.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/23/2023] [Indexed: 07/21/2023]
Abstract
Scaffold attachment factor B (SAFB) is a conserved RNA-binding protein that is essential for early mammalian development. However, the functions of SAFB in mouse embryonic stem cells (ESCs) have not been characterized. Using RNA immunoprecipitation followed by RNA-seq (RIP-seq), we examined the RNAs associated with SAFB in wild-type and SAFB/SAFB2 double-knockout ESCs. SAFB predominantly associated with introns of protein-coding genes through purine-rich motifs. The transcript most enriched in SAFB association was the lncRNA Malat1, which also contains a purine-rich region in its 5' end. Knockout of SAFB/SAFB2 led to differential expression of approximately 1000 genes associated with multiple biological processes, including apoptosis, cell division, and cell migration. Knockout of SAFB/SAFB2 also led to splicing changes in a set of genes that were largely distinct from those that exhibited changes in expression level. The spliced and nascent transcripts of many genes whose expression levels were positively regulated by SAFB also associated with high levels of SAFB, implying that SAFB binding promotes their expression. Reintroduction of SAFB into double-knockout cells restored gene expression toward wild-type levels, an effect again observable at the level of spliced and nascent transcripts. Proteomics analysis revealed a significant enrichment of nuclear speckle-associated and RS domain-containing proteins among SAFB interactors. Neither Xist nor Polycomb functions were dramatically altered in SAFB/2 knockout ESCs. Our findings suggest that among other potential functions in ESCs, SAFB promotes the expression of certain genes through its ability to bind nascent RNA.
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Affiliation(s)
- Rachel E Cherney
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Quinn E Eberhard
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Gilbert Giri
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Christine A Mills
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Proteomics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Alessandro Porrello
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Zhiyue Zhang
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - David White
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Jackson B Trotman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Laura E Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Proteomics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Daniel Dominguez
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - J Mauro Calabrese
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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16
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Limouse C, Smith OK, Jukam D, Fryer KA, Greenleaf WJ, Straight AF. Global mapping of RNA-chromatin contacts reveals a proximity-dominated connectivity model for ncRNA-gene interactions. Nat Commun 2023; 14:6073. [PMID: 37770513 PMCID: PMC10539311 DOI: 10.1038/s41467-023-41848-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 09/19/2023] [Indexed: 09/30/2023] Open
Abstract
Non-coding RNAs (ncRNAs) are transcribed throughout the genome and provide regulatory inputs to gene expression through their interaction with chromatin. Yet, the genomic targets and functions of most ncRNAs are unknown. Here we use chromatin-associated RNA sequencing (ChAR-seq) to map the global network of ncRNA interactions with chromatin in human embryonic stem cells and the dynamic changes in interactions during differentiation into definitive endoderm. We uncover general principles governing the organization of the RNA-chromatin interactome, demonstrating that nearly all ncRNAs exclusively interact with genes in close three-dimensional proximity to their locus and provide a model predicting the interactome. We uncover RNAs that interact with many loci across the genome and unveil thousands of unannotated RNAs that dynamically interact with chromatin. By relating the dynamics of the interactome to changes in gene expression, we demonstrate that activation or repression of individual genes is unlikely to be controlled by a single ncRNA.
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Affiliation(s)
- Charles Limouse
- Department of Biochemistry, Stanford University, Stanford, California, USA
| | - Owen K Smith
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, USA
| | - David Jukam
- Department of Biochemistry, Stanford University, Stanford, California, USA
| | - Kelsey A Fryer
- Department of Biochemistry, Stanford University, Stanford, California, USA
- Department of Genetics, Stanford University, Stanford, California, USA
| | | | - Aaron F Straight
- Department of Biochemistry, Stanford University, Stanford, California, USA.
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17
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Kletzien OA, Wuttke DS, Batey RT. The RNA-binding domain of hnRNP U extends beyond the RGG/RG motifs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558674. [PMID: 37786719 PMCID: PMC10541603 DOI: 10.1101/2023.09.20.558674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Heterogeneous nuclear ribonucleoprotein U (hnRNP U) is a ubiquitously expressed protein that regulates chromatin architecture through its interactions with numerous DNA, protein, and RNA partners. The RNA-binding domain (RBD) of hnRNP U was previously mapped to an RGG/RG element within its disordered C-terminal region, but little is understood about its binding mode and potential for selective RNA recognition. Analysis of publicly available hnRNP U enhanced UV crosslinking and immunoprecipitation (eCLIP) data identified high-confidence binding sites within human RNAs. We synthesized a set of diverse RNAs encompassing eleven of these identified crosslink sites for biochemical characterization using a combination of fluorescence anisotropy and electrophoretic mobility shift assays. These in vitro binding experiments with a rationally designed set of RNAs and hnRNP U domains revealed that the RGG/RG element is a small part of a more expansive RBD that encompasses most of the disordered C-terminal region. This RBD contains a second, previously experimentally uncharacterized RGG/RG element with RNA-binding properties comparable to the canonical RGG/RG element. These RGG/RG elements serve redundant functions, with neither serving as the primary RBD. While in isolation each RGG/RG element has modest affinity for RNA, together they significantly enhance the association of hnRNP U with RNA, enabling binding of most of the designed RNA set with low to mid-nanomolar binding affinities. Identification and characterization of the complete hnRNP U RBD highlights the perils of a reductionist approach to defining biochemical activities in this system and paves the way for a detailed investigation of its RNA-binding specificity.
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Affiliation(s)
- Otto A. Kletzien
- Department of Biochemistry, University of Colorado, Boulder, CO 80309-0596, USA
| | - Deborah S. Wuttke
- Department of Biochemistry, University of Colorado, Boulder, CO 80309-0596, USA
| | - Robert T. Batey
- Department of Biochemistry, University of Colorado, Boulder, CO 80309-0596, USA
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18
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Sapir T, Reiner O. HNRNPU's multi-tasking is essential for proper cortical development. Bioessays 2023; 45:e2300039. [PMID: 37439444 DOI: 10.1002/bies.202300039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 05/27/2023] [Accepted: 06/12/2023] [Indexed: 07/14/2023]
Abstract
Heterogeneous nuclear ribonucleoprotein U (HNRNPU) is a nuclear protein that plays a crucial role in various biological functions, such as RNA splicing and chromatin organization. HNRNPU/scaffold attachment factor A (SAF-A) activities are essential for regulating gene expression, DNA replication, genome integrity, and mitotic fidelity. These functions are critical to ensure the robustness of developmental processes, particularly those involved in shaping the human brain. As a result, HNRNPU is associated with various neurodevelopmental disorders (HNRNPU-related neurodevelopmental disorder, HNRNPU-NDD) characterized by developmental delay and intellectual disability. Our research demonstrates that the loss of HNRNPU function results in the death of both neural progenitor cells and post-mitotic neurons, with a higher sensitivity observed in the former. We reported that HNRNPU truncation leads to the dysregulation of gene expression and alternative splicing of genes that converge on several signaling pathways, some of which are likely to be involved in the pathology of HNRNPU-related NDD.
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Affiliation(s)
- Tamar Sapir
- Weizmann Institute of Science, Molecular Genetics and Molecular Neuroscience, Rehovot, Central, Israel
| | - Orly Reiner
- Weizmann Institute of Science, Molecular Genetics and Molecular Neuroscience, Rehovot, Central, Israel
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19
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Lim YH, Yoon G, Ryu Y, Jeong D, Song J, Kim YS, Ahn Y, Kook H, Kim YK. Human lncRNA SUGCT-AS1 Regulates the Proinflammatory Response of Macrophage. Int J Mol Sci 2023; 24:13315. [PMID: 37686120 PMCID: PMC10487982 DOI: 10.3390/ijms241713315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/20/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
Macrophages are the major primary immune cells that mediate the inflammatory response. In this process, long non-coding RNAs (lncRNAs) play an important, yet largely unknown role. Therefore, utilizing several publicly available RNA sequencing datasets, we predicted and selected lncRNAs that are differentially expressed in M1 or M2 macrophages and involved in the inflammatory response. We identified SUGCT-AS1, which is a human macrophage-specific lncRNA whose expression is increased upon M1 macrophage stimulation. Conditioned media of SUGCT-AS1-depleted M1 macrophages induced an inflammatory phenotype of vascular smooth muscle cells, which included increased expression of inflammatory genes (IL1B and IL6), decreased contractile marker proteins (ACTA2 and SM22α), and increased cell migration. Depletion of SUGCT-AS1 promoted the expression and secretion of proinflammatory cytokines, such as TNF, IL1B, and IL6, in M1 macrophages, and transcriptomic analysis showed that SUGCT-AS1 has functions related to inflammatory responses and cytokines. Furthermore, we found that SUGCT-AS1 directly binds to hnRNPU and regulates its nuclear-cytoplasmic translocation. This translocation of hnRNPU altered the proportion of the MALT1 isoforms by regulating the alternative splicing of MALT1, a mediator of NF-κB signaling. Overall, our findings suggest that lncRNAs can be used for future studies on macrophage regulation. Moreover, they establish the SUGCT-AS1/hnRNPU/MALT1 axis, which is a novel inflammatory regulatory mechanism in macrophages.
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Affiliation(s)
- Yeong-Hwan Lim
- Basic Research Laboratory for Vascular Remodeling, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- Department of Biochemistry, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
| | - Gwangho Yoon
- Division of Brain Disease Research, Department for Chronic Disease Convergence Research, Korea National Institute of Health, Cheongju 28159, Republic of Korea
| | - Yeongseo Ryu
- Department of Biochemistry, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
| | - Dahee Jeong
- Department of Biochemistry, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
| | - Juhyun Song
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
| | - Yong Sook Kim
- Basic Research Laboratory for Vascular Remodeling, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- Cell Regeneration Research Center, Chonnam National University Hospital, Gwangju 61469, Republic of Korea
- Biomedical Research Institute, Chonnam National University Hospital, Gwangju 61469, Republic of Korea
| | - Youngkeun Ahn
- Basic Research Laboratory for Vascular Remodeling, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- Cell Regeneration Research Center, Chonnam National University Hospital, Gwangju 61469, Republic of Korea
- Department of Cardiology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea
| | - Hyun Kook
- Basic Research Laboratory for Vascular Remodeling, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
- Department of Pharmacology, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
| | - Young-Kook Kim
- Basic Research Laboratory for Vascular Remodeling, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- Department of Biochemistry, Chonnam National University Medical School, Hwasun 58128, Republic of Korea
- BioMedical Sciences Graduate Program (BMSGP), Chonnam National University, Hwasun 58128, Republic of Korea
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20
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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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21
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Schede HH, Natarajan P, Chakraborty AK, Shrinivas K. A model for organization and regulation of nuclear condensates by gene activity. Nat Commun 2023; 14:4152. [PMID: 37438363 DOI: 10.1038/s41467-023-39878-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 07/03/2023] [Indexed: 07/14/2023] Open
Abstract
Condensation by phase separation has recently emerged as a mechanism underlying many nuclear compartments essential for cellular functions. Nuclear condensates enrich nucleic acids and proteins, localize to specific genomic regions, and often promote gene expression. How diverse properties of nuclear condensates are shaped by gene organization and activity is poorly understood. Here, we develop a physics-based model to interrogate how spatially-varying transcription activity impacts condensate properties and dynamics. Our model predicts that spatial clustering of active genes can enable precise localization and de novo nucleation of condensates. Strong clustering and high activity results in aspherical condensate morphologies. Condensates can flow towards distant gene clusters and competition between multiple clusters lead to stretched morphologies and activity-dependent repositioning. Overall, our model predicts and recapitulates morphological and dynamical features of diverse nuclear condensates and offers a unified mechanistic framework to study the interplay between non-equilibrium processes, spatially-varying transcription, and multicomponent condensates in cell biology.
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Affiliation(s)
- Halima H Schede
- School of Life Sciences, École Polytechnique Fédérale Lausanne, CH-1015, Lausanne, Switzerland
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pradeep Natarajan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Arup K Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Krishna Shrinivas
- NSF-Simons Center for Mathematical & Statistical Analysis of Biology, Harvard University, Cambridge, MA, USA.
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22
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Mattick JS, Amaral PP, Carninci P, Carpenter S, Chang HY, Chen LL, Chen R, Dean C, Dinger ME, Fitzgerald KA, Gingeras TR, Guttman M, Hirose T, Huarte M, Johnson R, Kanduri C, Kapranov P, Lawrence JB, Lee JT, Mendell JT, Mercer TR, Moore KJ, Nakagawa S, Rinn JL, Spector DL, Ulitsky I, Wan Y, Wilusz JE, Wu M. Long non-coding RNAs: definitions, functions, challenges and recommendations. Nat Rev Mol Cell Biol 2023; 24:430-447. [PMID: 36596869 PMCID: PMC10213152 DOI: 10.1038/s41580-022-00566-8] [Citation(s) in RCA: 403] [Impact Index Per Article: 403.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 01/05/2023]
Abstract
Genes specifying long non-coding RNAs (lncRNAs) occupy a large fraction of the genomes of complex organisms. The term 'lncRNAs' encompasses RNA polymerase I (Pol I), Pol II and Pol III transcribed RNAs, and RNAs from processed introns. The various functions of lncRNAs and their many isoforms and interleaved relationships with other genes make lncRNA classification and annotation difficult. Most lncRNAs evolve more rapidly than protein-coding sequences, are cell type specific and regulate many aspects of cell differentiation and development and other physiological processes. Many lncRNAs associate with chromatin-modifying complexes, are transcribed from enhancers and nucleate phase separation of nuclear condensates and domains, indicating an intimate link between lncRNA expression and the spatial control of gene expression during development. lncRNAs also have important roles in the cytoplasm and beyond, including in the regulation of translation, metabolism and signalling. lncRNAs often have a modular structure and are rich in repeats, which are increasingly being shown to be relevant to their function. In this Consensus Statement, we address the definition and nomenclature of lncRNAs and their conservation, expression, phenotypic visibility, structure and functions. We also discuss research challenges and provide recommendations to advance the understanding of the roles of lncRNAs in development, cell biology and disease.
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Affiliation(s)
- John S Mattick
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.
- UNSW RNA Institute, UNSW, Sydney, NSW, Australia.
| | - Paulo P Amaral
- INSPER Institute of Education and Research, São Paulo, Brazil
| | - Piero Carninci
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Human Technopole, Milan, Italy
| | - Susan Carpenter
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Howard Y Chang
- Center for Personal Dynamics Regulomes, Stanford University School of Medicine, Stanford, CA, USA
- Department of Dermatology, Stanford, CA, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Ling-Ling Chen
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Runsheng Chen
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich, UK
| | - Marcel E Dinger
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia
- UNSW RNA Institute, UNSW, Sydney, NSW, Australia
| | - Katherine A Fitzgerald
- Division of Innate Immunity, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | | | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Maite Huarte
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra, Pamplona, Spain
| | - Rory Johnson
- School of Biology and Environmental Science, University College Dublin, Dublin, Ireland
- Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Chandrasekhar Kanduri
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Philipp Kapranov
- Institute of Genomics, School of Medicine, Huaqiao University, Xiamen, China
| | - Jeanne B Lawrence
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Joshua T Mendell
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Timothy R Mercer
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Kathryn J Moore
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, USA
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - John L Rinn
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - David L Spector
- Cold Spring Harbour Laboratory, Cold Spring Harbour, NY, USA
| | - Igor Ulitsky
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Yue Wan
- Laboratory of RNA Genomics and Structure, Genome Institute of Singapore, A*STAR, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Jeremy E Wilusz
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX, USA
| | - Mian Wu
- Translational Research Institute, Henan Provincial People's Hospital, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
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23
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Wang B, Ji L, Bian Q. SATB1 regulates 3D genome architecture in T cells by constraining chromatin interactions surrounding CTCF-binding sites. Cell Rep 2023; 42:112323. [PMID: 37000624 DOI: 10.1016/j.celrep.2023.112323] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 01/20/2023] [Accepted: 03/16/2023] [Indexed: 04/01/2023] Open
Abstract
Special AT-rich sequence binding protein 1 (SATB1) has long been proposed to act as a global chromatin loop organizer in T cells. However, the exact functions of SATB1 in spatial genome organization remain elusive. Here we show that the depletion of SATB1 in human and murine T cells leads to transcriptional dysregulation for genes involved in T cell activation, as well as alterations of 3D genome architecture at multiple levels, including compartments, topologically associating domains, and loops. Importantly, SATB1 extensively colocalizes with CTCF throughout the genome. Depletion of SATB1 leads to increased chromatin contacts among and across the SATB1/CTCF co-occupied sites, thereby affecting the transcription of critical regulators of T cell activation. The loss of SATB1 does not affect CTCF occupancy but significantly reduces the retention of CTCF in the nuclear matrix. Collectively, our data show that SATB1 contributes to 3D genome organization by constraining chromatin topology surrounding CTCF-binding sites.
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Affiliation(s)
- Bao Wang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China; Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Luzhang Ji
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China; Shanghai Institute of Precision Medicine, Shanghai 200125, China
| | - Qian Bian
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China; Shanghai Institute of Precision Medicine, Shanghai 200125, China; Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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24
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Sharif J, Koseki H, Parrish NF. Bridging multiple dimensions: roles of transposable elements in higher-order genome regulation. Curr Opin Genet Dev 2023; 80:102035. [PMID: 37028152 DOI: 10.1016/j.gde.2023.102035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/01/2023] [Accepted: 03/05/2023] [Indexed: 04/09/2023]
Abstract
Transposable elements (TEs) such as endogenous retroviruses (ERVs), long interspersed nuclear elements (LINEs), and short interspersed nuclear elements (SINEs) occupy nearly half of typical mammalian genomes. Previous studies show that these parasitic elements, especially LINEs and ERVs, provide important activities promoting host germ cell and placental development, preimplantation embryogenesis, and maintenance of pluripotent stem cells. Despite being the most numerically abundant type of TEs in the genome, the consequences of SINEs on host genome regulation are less well characterized than those of ERVs and LINEs. Interestingly, recent findings reveal that SINEs recruit the key architectural protein CTCF (CCCTC-binding factor), indicating a role of these elements for 3D genome regulation. Higher-order nuclear structures are linked with important cellular functions such as gene regulation and DNA replication. SINEs and other TEs, therefore, may mediate distinct physiological processes with benefits to the host by modulating the 3D genome.
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Affiliation(s)
- Jafar Sharif
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Haruhiko Koseki
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan; Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Nicholas F Parrish
- Genome Immunobiology RIKEN Hakubi Research Team, RIKEN Center for Integrative Medical Sciences and RIKEN Cluster for Pioneering Research, Yokohama, Japan.
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25
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Schaeffer M, Nollmann M. Contributions of 3D chromatin structure to cell-type-specific gene regulation. Curr Opin Genet Dev 2023; 79:102032. [PMID: 36893484 DOI: 10.1016/j.gde.2023.102032] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/05/2023] [Accepted: 02/06/2023] [Indexed: 03/09/2023]
Abstract
Eukaryotic genomes are organized in 3D in a multiscale manner, and different mechanisms acting at each of these scales can contribute to transcriptional regulation. However, the large single-cell variability in 3D chromatin structures represents a challenge to understand how transcription may be differentially regulated between cell types in a robust and efficient manner. Here, we describe the different mechanisms by which 3D chromatin structure was shown to contribute to cell-type-specific transcriptional regulation. Excitingly, several novel methodologies able to measure 3D chromatin conformation and transcription in single cells in their native tissue context, or to detect the dynamics of cis-regulatory interactions, are starting to allow quantitative dissection of chromatin structure noise and relate it to how transcription may be regulated between different cell types and cell states.
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Affiliation(s)
- Marie Schaeffer
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, Montpellier, France
| | - Marcelo Nollmann
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, Montpellier, France.
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26
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Refaat AM, Nakata M, Husain A, Kosako H, Honjo T, Begum NA. HNRNPU facilitates antibody class-switch recombination through C-NHEJ promotion and R-loop suppression. Cell Rep 2023; 42:112284. [PMID: 36943867 DOI: 10.1016/j.celrep.2023.112284] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 10/23/2022] [Accepted: 03/03/2023] [Indexed: 03/22/2023] Open
Abstract
B cells generate functionally different classes of antibodies through class-switch recombination (CSR), which requires classical non-homologous end joining (C-NHEJ) to join the DNA breaks at the donor and acceptor switch (S) regions. We show that the RNA-binding protein HNRNPU promotes C-NHEJ-mediated S-S joining through the 53BP1-shieldin DNA-repair complex. Notably, HNRNPU binds to the S region RNA/DNA G-quadruplexes, contributing to regulating R-loop and single-stranded DNA (ssDNA) accumulation. HNRNPU is an intrinsically disordered protein that interacts with both C-NHEJ and R-loop complexes in an RNA-dependent manner. Strikingly, recruitment of HNRNPU and the C-NHEJ factors is highly sensitive to liquid-liquid phase separation inhibitors, suggestive of DNA-repair condensate formation. We propose that HNRNPU facilitates CSR by forming and stabilizing the C-NHEJ ribonucleoprotein complex and preventing excessive R-loop accumulation, which otherwise would cause persistent DNA breaks and aberrant DNA repair, leading to genomic instability.
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Affiliation(s)
- Ahmed M Refaat
- Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan; Zoology Department, Faculty of Science, Minia University, El-Minia 61519, Egypt
| | - Mikiyo Nakata
- Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Afzal Husain
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh 202002, India
| | - Hidetaka Kosako
- Division of Cell Signaling, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Tasuku Honjo
- Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
| | - Nasim A Begum
- Department of Immunology and Genomic Medicine, Center for Cancer Immunotherapy and Immunobiology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
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27
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Long noncoding RNAs in cardiovascular disease. Curr Opin Cardiol 2023; 38:179-192. [PMID: 36930221 PMCID: PMC10090314 DOI: 10.1097/hco.0000000000001041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
PURPOSE OF REVIEW Here, we review recent findings on the role of long noncoding RNAs (lncRNAs) in cardiovascular disease (CVD). In addition, we highlight some of the latest findings in lncRNA biology, providing an outlook for future avenues of lncRNA research in CVD. RECENT FINDINGS Recent publications provide translational evidence from patient studies and animal models for the role of specific lncRNAs in CVD. The molecular effector mechanisms of these lncRNAs are diverse. Overall, cell-type selective modulation of gene expression is the largest common denominator. New methods, such as single-cell profiling and CRISPR/Cas9-screening, reveal additional novel mechanistic principles: For example, many lncRNAs establish RNA-based spatial compartments that concentrate effector proteins. Also, RNA modifications and splicing features can be determinants of lncRNA function. SUMMARY lncRNA research is passing the stage of enumerating lncRNAs or recording simplified on-off expression switches. Mechanistic analyses are starting to reveal overarching principles of how lncRNAs can function. Exploring these principles with decisive genetic testing in vivo remains the ultimate test to discern how lncRNA loci, by RNA motifs or DNA elements, affect CVD pathophysiology.
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28
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Chen LJ, Chen X, Niu XH, Peng XF. LncRNAs in colorectal cancer: Biomarkers to therapeutic targets. Clin Chim Acta 2023; 543:117305. [PMID: 36966964 DOI: 10.1016/j.cca.2023.117305] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
Colorectal cancer (CRC) is the third leading cause of cancer-related death in men and women worldwide. As early detection is associated with lower mortality, novel biomarkers are urgently needed for timely diagnosis and appropriate management of patients to achieve the best therapeutic response. Long noncoding RNAs (lncRNAs) have been reported to play essential roles in CRC progression. Accordingly, the regulatory roles of lncRNAs should be better understood in general and for identifying diagnostic, prognostic and predictive biomarkers in CRC specifically. In this review, the latest advances on the potential diagnostic and prognostic lncRNAs as biomarkers in CRC samples were highlighted, Current knowledge on dysregulated lncRNAs and their potential molecular mechanisms were summarized. The potential therapeutic implications and challenges for future and ongoing research in the field were also discussed. Finally, novel insights on the underlying mechanisms of lncRNAs were examined as to their potential role as biomarkers and therapeutic targets in CRC. This review may be used to design future studies and advanced investigations on lncRNAs as biomarkers for the diagnosis, prognosis and therapy in CRC.
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Affiliation(s)
- Ling-Juan Chen
- Department of Clinical Laboratory, Qingyuan People's Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan 511518, Guangdong Province, China
| | - Xiang Chen
- Department of General Surgery, Qingyuan People's Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan 511518, Guangdong Province, China
| | - Xiao-Hua Niu
- Department of General Surgery, Qingyuan People's Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan 511518, Guangdong Province, China
| | - Xiao-Fei Peng
- Department of General Surgery, Qingyuan People's Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan 511518, Guangdong Province, China.
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29
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Stamidis N, Żylicz JJ. RNA-mediated heterochromatin formation at repetitive elements in mammals. EMBO J 2023; 42:e111717. [PMID: 36847618 PMCID: PMC10106986 DOI: 10.15252/embj.2022111717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/12/2022] [Accepted: 02/07/2023] [Indexed: 03/01/2023] Open
Abstract
The failure to repress transcription of repetitive genomic elements can lead to catastrophic genome instability and is associated with various human diseases. As such, multiple parallel mechanisms cooperate to ensure repression and heterochromatinization of these elements, especially during germline development and early embryogenesis. A vital question in the field is how specificity in establishing heterochromatin at repetitive elements is achieved. Apart from trans-acting protein factors, recent evidence points to a role of different RNA species in targeting repressive histone marks and DNA methylation to these sites in mammals. Here, we review recent discoveries on this topic and predominantly focus on the role of RNA methylation, piRNAs, and other localized satellite RNAs.
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Affiliation(s)
- Nikolaos Stamidis
- Novo Nordisk Foundation Center for Stem Cell Medicine, reNEW, University of Copenhagen, Copenhagen, Denmark
| | - Jan Jakub Żylicz
- Novo Nordisk Foundation Center for Stem Cell Medicine, reNEW, University of Copenhagen, Copenhagen, Denmark
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30
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Tang J, Wang X, Xiao D, Liu S, Tao Y. The chromatin-associated RNAs in gene regulation and cancer. Mol Cancer 2023; 22:27. [PMID: 36750826 PMCID: PMC9903551 DOI: 10.1186/s12943-023-01724-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/16/2023] [Indexed: 02/09/2023] Open
Abstract
Eukaryotic genomes are prevalently transcribed into many types of RNAs that translate into proteins or execute gene regulatory functions. Many RNAs associate with chromatin directly or indirectly and are called chromatin-associated RNAs (caRNAs). To date, caRNAs have been found to be involved in gene and transcriptional regulation through multiple mechanisms and have important roles in different types of cancers. In this review, we first present different categories of caRNAs and the modes of interaction between caRNAs and chromatin. We then detail the mechanisms of chromatin-associated nascent RNAs, chromatin-associated noncoding RNAs and emerging m6A on caRNAs in transcription and gene regulation. Finally, we discuss the roles of caRNAs in cancer as well as epigenetic and epitranscriptomic mechanisms contributing to cancer, which could provide insights into the relationship between different caRNAs and cancer, as well as tumor treatment and intervention.
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Affiliation(s)
- Jun Tang
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078 Hunan China ,grid.216417.70000 0001 0379 7164Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), NHC Key Laboratory of Carcinogenesis (Central South University), Cancer Research Institute and School of Basic Medicine, Central South University, Changsha, 410078 Hunan China
| | - Xiang Wang
- grid.216417.70000 0001 0379 7164Department of Thoracic Surgery, Hunan Key Laboratory of Early Diagnosis and Precision Therapy in Lung Cancer, Second Xiangya Hospital, Central South University, Changsha, 410011 China
| | - Desheng Xiao
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
| | - Shuang Liu
- Department of Oncology, Institute of Medical Sciences, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
| | - Yongguang Tao
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410078, Hunan, China. .,Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), NHC Key Laboratory of Carcinogenesis (Central South University), Cancer Research Institute and School of Basic Medicine, Central South University, Changsha, 410078, Hunan, China. .,Department of Thoracic Surgery, Hunan Key Laboratory of Early Diagnosis and Precision Therapy in Lung Cancer, Second Xiangya Hospital, Central South University, Changsha, 410011, China. .,Department of Pathology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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31
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Soujanya M, Bihani A, Hajirnis N, Pathak RU, Mishra RK. Nuclear architecture and the structural basis of mitotic memory. CHROMOSOME RESEARCH : AN INTERNATIONAL JOURNAL ON THE MOLECULAR, SUPRAMOLECULAR AND EVOLUTIONARY ASPECTS OF CHROMOSOME BIOLOGY 2023; 31:8. [PMID: 36725757 DOI: 10.1007/s10577-023-09714-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023]
Abstract
The nucleus is a complex organelle that hosts the genome and is essential for vital processes like DNA replication, DNA repair, transcription, and splicing. The genome is non-randomly organized in the three-dimensional space of the nucleus. This functional sub-compartmentalization was thought to be organized on the framework of nuclear matrix (NuMat), a non-chromatin scaffold that functions as a substratum for various molecular processes of the nucleus. More recently, nuclear bodies or membrane-less subcompartments of the nucleus are thought to arise due to phase separation of chromatin, RNA, and proteins. The nuclear architecture is an amalgamation of the relative organization of chromatin, epigenetic landscape, the nuclear bodies, and the nucleoskeleton in the three-dimensional space of the nucleus. During mitosis, the nucleus undergoes drastic changes in morphology to the degree that it ceases to exist as such; various nuclear components, including the envelope that defines the nucleus, disintegrate, and the chromatin acquires mitosis-specific epigenetic marks and condenses to form chromosome. Upon mitotic exit, chromosomes are decondensed, re-establish hierarchical genome organization, and regain epigenetic and transcriptional status similar to that of the mother cell. How this mitotic memory is inherited during cell division remains a puzzle. NuMat components that are a part of the mitotic chromosome in the form of mitotic chromosome scaffold (MiCS) could potentially be the seeds that guide the relative re-establishment of the epigenome, chromosome territories, and the nuclear bodies. Here, we synthesize the advances towards understanding cellular memory of nuclear architecture across mitosis and propose a hypothesis that a subset of NuMat proteome essential for nucleation of various nuclear bodies are retained in MiCS to serve as seeds of mitotic memory, thus ensuring the daughter cells re-establish the complex status of nuclear architecture similar to that of the mother cells, thereby maintaining the pre-mitotic transcriptional status.
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Affiliation(s)
- Mamilla Soujanya
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Ashish Bihani
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Nikhil Hajirnis
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, USA
| | - Rashmi U Pathak
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India.
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India.
- TIGS - Tata Institute for Genetics and Society, Bangalore, India.
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32
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Moreno-Andrés D, Holl K, Antonin W. The second half of mitosis and its implications in cancer biology. Semin Cancer Biol 2023; 88:1-17. [PMID: 36436712 DOI: 10.1016/j.semcancer.2022.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/26/2022]
Abstract
The nucleus undergoes dramatic structural and functional changes during cell division. With the entry into mitosis, in human cells the nuclear envelope breaks down, chromosomes rearrange into rod-like structures which are collected and segregated by the spindle apparatus. While these processes in the first half of mitosis have been intensively studied, much less is known about the second half of mitosis, when a functional nucleus reforms in each of the emerging cells. Here we review our current understanding of mitotic exit and nuclear reformation with spotlights on the links to cancer biology.
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Affiliation(s)
- Daniel Moreno-Andrés
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany.
| | - Kristin Holl
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
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33
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Shen W, Zhang Y, Shi M, Ye B, Yin M, Li P, Shi S, Jin Y, Zhang Z, Zhang MQ, Chen Y, Zhao Z. Profiling and characterization of constitutive chromatin-enriched RNAs. iScience 2022; 25:105349. [DOI: 10.1016/j.isci.2022.105349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/29/2022] [Accepted: 10/11/2022] [Indexed: 10/31/2022] Open
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Ponting CP, Haerty W. Genome-Wide Analysis of Human Long Noncoding RNAs: A Provocative Review. Annu Rev Genomics Hum Genet 2022; 23:153-172. [PMID: 35395170 DOI: 10.1146/annurev-genom-112921-123710] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Do long noncoding RNAs (lncRNAs) contribute little or substantively to human biology? To address how lncRNA loci and their transcripts, structures, interactions, and functions contribute to human traits and disease, we adopt a genome-wide perspective. We intend to provoke alternative interpretation of questionable evidence and thorough inquiry into unsubstantiated claims. We discuss pitfalls of lncRNA experimental and computational methods as well as opposing interpretations of their results. The majority of evidence, we argue, indicates that most lncRNA transcript models reflect transcriptional noise or provide minor regulatory roles, leaving relatively few human lncRNAs that contribute centrally to human development, physiology, or behavior. These important few tend to be spliced and better conserved but lack a simple syntax relating sequence to structure and mechanism, and so resist simple categorization. This genome-wide view should help investigators prioritize individual lncRNAs based on their likely contribution to human biology.
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Affiliation(s)
- Chris P Ponting
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom;
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35
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Abstract
Virtually all cell types have the same DNA, yet each type exhibits its own cell-specific pattern of gene expression. During the brief period of mitosis, the chromosomes exhibit changes in protein composition and modifications, a marked condensation, and a consequent reduction in transcription. Yet as cells exit mitosis, they reactivate their cell-specific programs with high fidelity. Initially, the field focused on the subset of transcription factors that are selectively retained in, and hence bookmark, chromatin in mitosis. However, recent studies show that many transcription factors can be retained in mitotic chromatin and that, surprisingly, such retention can be due to nonspecific chromatin binding. Here, we review the latest studies focusing on low-level transcription via promoters, rather than enhancers, as contributing to mitotic memory, as well as new insights into chromosome structure dynamics, histone modifications, cell cycle signaling, and nuclear envelope proteins that together ensure the fidelity of gene expression through a round of mitosis.
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Affiliation(s)
- Kenji Ito
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
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36
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Podgornaya OI. Nuclear organization by satellite DNA, SAF-A/hnRNPU and matrix attachment regions. Semin Cell Dev Biol 2022; 128:61-68. [PMID: 35484025 DOI: 10.1016/j.semcdb.2022.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 12/15/2022]
Abstract
The need of large-scale chromatin organization in the nucleus has become more and more appreciated. The higher order nuclear organization ultimately regulate a plethora of biological processes including transcription, DNA replication, and DNA repair. In this context, it is of critical importance to understand the mechanisms that allow higher order nuclear organization. Scaffold Attachment Factor A (SAF-A/hnRNPU), which was originally identified as the component of nuclear matrix, has emerged as an important regulator of higher order nuclear organization. It is shown that SAF-A/hnRNPU binds to tandem repeats (TRs) and scaffold/matrix attachment regions (S/MAR) in a sequence-non-specific, but structure-specific manner (e.g. DNA curvature). Recent studies showed that SAF-A interacts with chromatin-associated RNAs (caRNAs) to regulate interphase chromatin structures in a transcription-dependent manner. It is proposed that SAF-A/hnRNPU and caRNAs form a dynamic, transcriptionally responsive chromatin mesh that organizes chromatin in a large scale. The common structural features of S/MAR and pericentromeric (periCEN) TR promotes SAF-A-mediated association with each other. Collectively a model is presented wherein SAF-A/hnRNPU and periCEN TR are the key players in large-scale nuclear organization that supports general transcription.
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Affiliation(s)
- O I Podgornaya
- Institute of Cytology RAS, St. Petersburg State University, Russia.
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37
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Nickerson JA. The ribonucleoprotein network of the nucleus: a historical perspective. Curr Opin Genet Dev 2022; 75:101940. [PMID: 35777349 DOI: 10.1016/j.gde.2022.101940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 05/16/2022] [Accepted: 05/24/2022] [Indexed: 11/28/2022]
Abstract
There is a long experimental history supporting the principle that RNA is essential for normal nuclear and chromatin architecture. Most of the genome is transcribed into RNA but only 2% of the sequence codes for proteins. In the nucleus, most non-coding RNA, packaged in proteins, is bound into structures including chromatin and a non-chromatin scaffolding, the nuclear matrix, which was first observed by electron microscopy. Removing nuclear RNA or inhibiting its transcription causes the condensation of chromatin, showing the importance of RNA in spatially and functionally organizing the genome. Today, powerful techniques for the molecular characterization of RNA and for mapping its spatial organization in the nucleus have provided molecular detail to these principles.
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Affiliation(s)
- Jeffrey A Nickerson
- Division of Genes & Development, Department of Pediatrics, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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38
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A lifelong duty: how Xist maintains the inactive X chromosome. Curr Opin Genet Dev 2022; 75:101927. [PMID: 35717799 PMCID: PMC9472561 DOI: 10.1016/j.gde.2022.101927] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/10/2022] [Accepted: 05/14/2022] [Indexed: 11/22/2022]
Abstract
Female eutherians transcriptionally silence one X chromosome to balance gene dosage between the sexes. X-chromosome inactivation (XCI) is initiated by the lncRNA Xist, which assembles many proteins within the inactive X chromosome (Xi) to trigger gene silencing and heterochromatin formation. It is well established that gene silencing on the Xi is maintained through repressive epigenetic processes, including histone deacetylation and DNA methylation. Recent studies revealed a new mechanism where RNA-binding proteins that interact directly with the RNA contribute to the maintenance of Xist localization and gene silencing. In addition, a surprising plasticity of the Xi was uncovered with many genes becoming upregulated upon experimental deletion of Xist. Intriguingly, immune cells normally lose Xist from the Xi, suggesting that thisXist dependence is utilized in vivo to dynamically regulate gene expression from the Xi. These new studies expose fundamental regulatory mechanisms for the chromatin association of RNAs, highlight the need for studying the maintenance of XCI and Xist localization in a gene- and cell-type-specific manner, and are likely to have clinical impact.
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39
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Huang X, Bashkenova N, Hong Y, Lyu C, Guallar D, Hu Z, Malik V, Li D, Wang H, Shen X, Zhou H, Wang J. A TET1-PSPC1-Neat1 molecular axis modulates PRC2 functions in controlling stem cell bivalency. Cell Rep 2022; 39:110928. [PMID: 35675764 PMCID: PMC9214724 DOI: 10.1016/j.celrep.2022.110928] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 03/29/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
TET1 maintains hypomethylation at bivalent promoters through its catalytic activity in embryonic stem cells (ESCs). However, TET1 catalytic activity-independent function in regulating bivalent genes is not well understood. Using a proteomics approach, we map the TET1 interactome in ESCs and identify PSPC1 as a TET1 partner. Genome-wide location analysis reveals that PSPC1 functionally associates with TET1 and Polycomb repressive complex-2 (PRC2). We establish that PSPC1 and TET1 repress, and the lncRNA Neat1 activates, bivalent gene expression. In ESCs, Neat1 is preferentially bound to PSPC1 alongside its PRC2 association at bivalent promoters. During the ESC-to-epiblast-like stem cell (EpiLC) transition, PSPC1 and TET1 maintain PRC2 chromatin occupancy at bivalent gene promoters, while Neat1 facilitates the activation of certain bivalent genes by promoting PRC2 binding to their mRNAs. Our study demonstrates a TET1-PSPC1-Neat1 molecular axis that modulates PRC2-binding affinity to chromatin and bivalent gene transcripts in controlling stem cell bivalency.
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Affiliation(s)
- Xin Huang
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Nazym Bashkenova
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Yantao Hong
- Tsinghua Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Cong Lyu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Diana Guallar
- Center for Research in Molecular Medicine and Chronic Diseases (CiMUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Zhe Hu
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Vikas Malik
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Dan Li
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Hailin Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaohua Shen
- Tsinghua Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongwei Zhou
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jianlong Wang
- Department of Medicine, Columbia Center for Human Development, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA.
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40
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Maccaroni K, La Torre M, Burla R, Saggio I. Phase Separation in the Nucleus and at the Nuclear Periphery during Post-Mitotic Nuclear Envelope Reformation. Cells 2022; 11:cells11111749. [PMID: 35681444 PMCID: PMC9179440 DOI: 10.3390/cells11111749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
Membrane-enclosed organelle compartmentalization is not the only way by which cell processes are spatially organized. Phase separation is emerging as a new driver in the organization of membrane-less compartments and biological processes. Liquid–liquid phase separation has been indicated as a new way to control the kinetics of molecular reactions and is based on weak multivalent interactions affecting the stoichiometry of the molecules involved. In the nucleus, liquid–liquid phase separation may represent an ancestral means of controlling genomic activity by forming discrete chromatin regions, regulating transcriptional activity, contributing to the assembly of DNA damage response foci, and controlling the organization of chromosomes. Liquid–liquid phase separation also contributes to chromatin function through its role in the reorganization of the nuclear periphery in the post-mitotic phase. Herein, we describe the basic principles regulating liquid–liquid phase separation, analyze examples of phase separation occurring in the nucleus, and dedicate attention to the implication of liquid–liquid phase separation in the reorganization of the nuclear periphery by the endosomal sorting complexes required for transport (ESCRT) machinery. Although some caution is warranted, current scientific knowledge allows for the hypothesis that many factors and processes in the cell are yet to be discovered which are functionally associated with phase separation.
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Affiliation(s)
- Klizia Maccaroni
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Mattia La Torre
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
| | - Romina Burla
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Isabella Saggio
- Department of Biology and Biotechnology, Sapienza University, 00185 Rome, Italy; (K.M.); (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
- Institute of Structural Biology, Nanyang Technological University, Singapore 639798, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore
- Correspondence:
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41
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Razin SV, Ulianov SV. Genome-Directed Cell Nucleus Assembly. BIOLOGY 2022; 11:biology11050708. [PMID: 35625436 PMCID: PMC9138775 DOI: 10.3390/biology11050708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Speckles and other nuclear bodies, the nucleolus and perinucleolar zone, transcription/replication factories and the lamina-associated compartment, serve as a structural basis for various genomic functions. In turn, genome activity and specific chromatin 3D organization directly impact the integrity of intranuclear assemblies, initiating/facilitating their formation and dictating their composition. Thus, the large-scale nucleus structure and genome activity mutually influence each other. The cell nucleus is frequently considered a compartment in which the genome is placed to protect it from external forces. Here, we discuss the evidence demonstrating that the cell nucleus should be considered, rather, as structure built around the folded genome. Decondensing chromosomes provide a scaffold for the assembly of the nuclear envelope after mitosis, whereas genome activity directs the assembly of various nuclear compartments, including nucleolus, speckles and transcription factories. Abstract The cell nucleus is frequently considered a cage in which the genome is placed to protect it from various external factors. Inside the nucleus, many functional compartments have been identified that are directly or indirectly involved in implementing genomic DNA’s genetic functions. For many years, it was assumed that these compartments are assembled on a proteinaceous scaffold (nuclear matrix), which provides a structural milieu for nuclear compartmentalization and genome folding while simultaneously offering some rigidity to the cell nucleus. The results of research in recent years have made it possible to consider the cell nucleus from a different angle. From the “box” in which the genome is placed, the nucleus has become a kind of mobile exoskeleton, which is formed around the packaged genome, under the influence of transcription and other processes directly related to the genome activity. In this review, we summarize the main arguments in favor of this point of view by analyzing the mechanisms that mediate cell nucleus assembly and support its resistance to mechanical stresses.
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Affiliation(s)
- Sergey V. Razin
- Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
- Correspondence: or
| | - Sergey V. Ulianov
- Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
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42
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An added layer of repression for human genes. Nature 2022; 604:41-42. [PMID: 35354969 DOI: 10.1038/d41586-022-00519-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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43
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Systematic mapping of nuclear domain-associated transcripts reveals speckles and lamina as hubs of functionally distinct retained introns. Mol Cell 2022; 82:1035-1052.e9. [PMID: 35182477 DOI: 10.1016/j.molcel.2021.12.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 12/22/2022]
Abstract
The nucleus is highly compartmentalized through the formation of distinct classes of membraneless domains. However, the composition and function of many of these structures are not well understood. Using APEX2-mediated proximity labeling and RNA sequencing, we surveyed human transcripts associated with nuclear speckles, several additional domains, and the lamina. Remarkably, speckles and lamina are associated with distinct classes of retained introns enriched in genes that function in RNA processing, translation, and the cell cycle, among other processes. In contrast to the lamina-proximal introns, retained introns associated with speckles are relatively short, GC-rich, and enriched for functional sites of RNA-binding proteins that are concentrated in these domains. They are also highly differentially regulated across diverse cellular contexts, including the cell cycle. Thus, our study provides a resource of nuclear domain-associated transcripts and further reveals speckles and lamina as hubs of distinct populations of retained introns linked to gene regulation and cell cycle progression.
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44
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Wang D, Ye R, Cai Z, Xue Y. Emerging roles of RNA-RNA interactions in transcriptional regulation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2022; 13:e1712. [PMID: 35042277 DOI: 10.1002/wrna.1712] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 12/07/2021] [Accepted: 12/16/2021] [Indexed: 12/26/2022]
Abstract
Pervasive transcription of the human genome generates a massive amount of noncoding RNAs (ncRNAs) that lack protein-coding potential but play crucial roles in development, differentiation, and tumorigenesis. To achieve these biological functions, ncRNAs must first fold into intricate structures via intramolecular RNA-RNA interactions (RRIs) and then interact with different RNA substrates via intermolecular RRIs. RRIs are usually facilitated, stabilized, or mediated by RNA-binding proteins. With this guiding principle, several protein-based high-throughput methods have been developed for unbiased mapping of defined or all RNA-binding protein-mediated RRIs in various species and cell lines. In addition, some chemical-based approaches are also powerful to detect RRIs globally based on the fact that RNA duplex can be cross-linked by psoralen or its derivative 4'-aminomethyltrioxsalen. These efforts have significantly expanded our understanding of RRIs in determining the specificity and variability of gene regulation. Here, we review the current knowledge of the regulatory roles of RRI, focusing on their emerging roles in transcriptional regulation and nuclear body formation. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Di Wang
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Rong Ye
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhaokui Cai
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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45
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Faber MW, Vo TV. Long RNA-Mediated Chromatin Regulation in Fission Yeast and Mammals. Int J Mol Sci 2022; 23:968. [PMID: 35055152 PMCID: PMC8778201 DOI: 10.3390/ijms23020968] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/07/2022] [Accepted: 01/13/2022] [Indexed: 12/12/2022] Open
Abstract
As part of a complex network of genome control, long regulatory RNAs exert significant influences on chromatin dynamics. Understanding how this occurs could illuminate new avenues for disease treatment and lead to new hypotheses that would advance gene regulatory research. Recent studies using the model fission yeast Schizosaccharomyces pombe (S. pombe) and powerful parallel sequencing technologies have provided many insights in this area. This review will give an overview of key findings in S. pombe that relate long RNAs to multiple levels of chromatin regulation: histone modifications, gene neighborhood regulation in cis and higher-order chromosomal ordering. Moreover, we discuss parallels recently found in mammals to help bridge the knowledge gap between the study systems.
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Affiliation(s)
| | - Tommy V. Vo
- Department of Biochemistry and Molecular Biology, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA;
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46
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Connolly C, Takahashi S, Miura H, Hiratani I, Gilbert N, Donaldson AD, Hiraga SI. SAF-A promotes origin licensing and replication fork progression to ensure robust DNA replication. J Cell Sci 2022; 135:jcs258991. [PMID: 34888666 DOI: 10.1242/jcs.258991] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 12/02/2021] [Indexed: 11/20/2022] Open
Abstract
The organisation of chromatin is closely intertwined with biological activities of chromosome domains, including transcription and DNA replication status. Scaffold-attachment factor A (SAF-A), also known as heterogeneous nuclear ribonucleoprotein U (HNRNPU), contributes to the formation of open chromatin structure. Here, we demonstrate that SAF-A promotes the normal progression of DNA replication and enables resumption of replication after inhibition. We report that cells depleted of SAF-A show reduced origin licensing in G1 phase and, consequently, reduced origin activation frequency in S phase. Replication forks also progress less consistently in cells depleted of SAF-A, contributing to reduced DNA synthesis rate. Single-cell replication timing analysis revealed two distinct effects of SAF-A depletion: first, the boundaries between early- and late-replicating domains become more blurred; and second, SAF-A depletion causes replication timing changes that tend to bring regions of discordant domain compartmentalisation and replication timing into concordance. Associated with these defects, SAF-A-depleted cells show elevated formation of phosphorylated histone H2AX (γ-H2AX) and tend to enter quiescence. Overall, we find that SAF-A protein promotes robust DNA replication to ensure continuing cell proliferation.
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Affiliation(s)
- Caitlin Connolly
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Saori Takahashi
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Hisashi Miura
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Ichiro Hiratani
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Nick Gilbert
- MRC Human Genetics Unit, The University of Edinburgh, Crewe Rd, Edinburgh EH4 2XU, UK
| | - Anne D Donaldson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Shin-Ichiro Hiraga
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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47
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Palacio M, Taatjes DJ. Merging Established Mechanisms with New Insights: Condensates, Hubs, and the Regulation of RNA Polymerase II Transcription. J Mol Biol 2022; 434:167216. [PMID: 34474085 PMCID: PMC8748285 DOI: 10.1016/j.jmb.2021.167216] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 01/17/2023]
Abstract
The regulation of RNA polymerase II (pol II) transcription requires a complex and context-specific array of proteins and protein complexes, as well as nucleic acids and metabolites. Every major physiological process requires coordinated transcription of specific sets of genes at the appropriate time, and a breakdown in this regulation is a hallmark of human disease. A proliferation of recent studies has revealed that many general transcription components, including sequence-specific, DNA-binding transcription factors, Mediator, and pol II itself, are capable of liquid-liquid phase separation, to form condensates that partition these factors away from the bulk aqueous phase. These findings hold great promise for next-level understanding of pol II transcription; however, many mechanistic aspects align with more conventional models, and whether phase separation per se regulates pol II activity in cells remains controversial. In this review, we describe the conventional and condensate-dependent models, and why their similarities and differences are important. We also compare and contrast these models in the context of genome organization and pol II transcription (initiation, elongation, and termination), and highlight the central role of RNA in these processes. Finally, we discuss mutations that disrupt normal partitioning of transcription factors, and how this may contribute to disease.
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Affiliation(s)
- Megan Palacio
- Dept. of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Dylan J. Taatjes
- Dept. of Biochemistry, University of Colorado, Boulder, CO, USA,corresponding author;
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48
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RNA gradients: Shapers of 3D genome architecture. Curr Opin Cell Biol 2022; 74:7-12. [PMID: 34998095 DOI: 10.1016/j.ceb.2021.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 01/13/2023]
Abstract
A growing body of evidence points to a role of nuclear RNAs (nucRNAs) in shaping the three-dimensional (3D) architecture of the genome within the nucleus of a eukaryotic cell. nucRNAs are non-homogeneously distributed within the nucleus where they can form global and local gradients that might contribute to instructing the formation and coordinating the function of different types of 3D genome structures. In this article, we highlight the available literature supporting a role of nucRNAs as 3D genome shapers and propose that nucRNA gradients are key mediators of genome structure and function.
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49
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Kolpa HJ, Creamer KM, Hall LL, Lawrence JB. SAF-A mutants disrupt chromatin structure through dominant negative effects on RNAs associated with chromatin. Mamm Genome 2021; 33:366-381. [PMID: 34859278 PMCID: PMC9114059 DOI: 10.1007/s00335-021-09935-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/02/2021] [Indexed: 11/21/2022]
Abstract
Here we provide a brief review of relevant background before presenting results of our investigation into the interplay between scaffold attachment factor A (SAF-A), chromatin-associated RNAs, and DNA condensation. SAF-A, also termed heterogenous nuclear protein U (hnRNP U), is a ubiquitous nuclear scaffold protein that was implicated in XIST RNA localization to the inactive X-chromosome (Xi) but also reported to maintain open DNA packaging in euchromatin. Here we use several means to perturb SAF-A and examine potential impacts on the broad association of RNAs on euchromatin, and on chromatin compaction. SAF-A has an N-terminal DNA binding domain and C-terminal RNA binding domain, and a prominent model has been that the protein provides a single-molecule bridge between XIST RNA and chromatin. Here analysis of the impact of SAF-A on broad RNA-chromatin interactions indicate greater biological complexity. We focus on SAF-A's role with repeat-rich C0T-1 hnRNA (repeat-rich heterogeneous nuclear RNA), shown recently to comprise mostly intronic sequences of pre-mRNAs and diverse long non-coding RNAs (lncRNAs). Our results show that SAF-A mutants cause dramatic changes to cytological chromatin condensation through dominant negative effects on C0T-1 RNA's association with euchromatin, and likely other nuclear scaffold factors. In contrast, depletion of SAF-A by RNA interference (RNAi) had no discernible impact on C0T-1 RNA, nor did it cause similarly marked chromatin changes as did three different SAF-A mutations. Overall results support the concept that repeat-rich, chromatin-associated RNAs interact with multiple RNA binding proteins (RBPs) in a complex dynamic meshwork that is integral to larger-scale chromatin architecture and collectively influences cytological-scale DNA condensation.
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Affiliation(s)
- Heather J Kolpa
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.,Ashfield MedComms, Lyndhurst, NJ, 07071, USA
| | - Kevin M Creamer
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.,Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Lisa L Hall
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA. .,Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
| | - Jeanne B Lawrence
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, 01655, USA. .,Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01655, USA.
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Marenda M, Lazarova E, Gilbert N. The role of SAF-A/hnRNP U in regulating chromatin structure. Curr Opin Genet Dev 2021; 72:38-44. [PMID: 34823151 DOI: 10.1016/j.gde.2021.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/15/2021] [Accepted: 10/27/2021] [Indexed: 01/01/2023]
Abstract
Scaffold attachment factor A (SAF-A) or hnRNP U is a nuclear RNA-binding protein with a well-documented role in processing newly transcribed RNA. Recent studies also indicate that SAF-A can oligomerise in an ATP-dependent manner and interact with RNA to form a dynamic nuclear mesh. This mesh is thought to regulate nuclear and chromatin architecture, yet a mechanistic understanding is lacking. Here, we review developments in the field to understand how the SAF-A/RNA mesh affects chromatin organisation in interphase and mitosis. As SAF-A has an intrinsically disordered domain we discuss how the chromatin mesh is related to nuclear phase-separated condensates, which in other situations have been shown to regulate transcription and cell functions. Finally, we infer possible links between diseases emerging from SAF-A mutations and its role in chromatin organisation and regulation.
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Affiliation(s)
- Mattia Marenda
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Elena Lazarova
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Nick Gilbert
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK.
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