1
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Tamburri S, Rustichelli S, Amato S, Pasini D. Navigating the complexity of Polycomb repression: Enzymatic cores and regulatory modules. Mol Cell 2024; 84:3381-3405. [PMID: 39178860 DOI: 10.1016/j.molcel.2024.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 07/12/2024] [Accepted: 07/30/2024] [Indexed: 08/26/2024]
Abstract
Polycomb proteins are a fundamental repressive system that plays crucial developmental roles by orchestrating cell-type-specific transcription programs that govern cell identity. Direct alterations of Polycomb activity are indeed implicated in human pathologies, including developmental disorders and cancer. General Polycomb repression is coordinated by three distinct activities that regulate the deposition of two histone post-translational modifications: tri-methylation of histone H3 lysine 27 (H3K27me3) and histone H2A at lysine 119 (H2AK119ub1). These activities exist in large and heterogeneous multiprotein ensembles consisting of common enzymatic cores regulated by heterogeneous non-catalytic modules composed of a large number of accessory proteins with diverse biochemical properties. Here, we have analyzed the current molecular knowledge, focusing on the functional interaction between the core enzymatic activities and their regulation mediated by distinct accessory modules. This provides a comprehensive analysis of the molecular details that control the establishment and maintenance of Polycomb repression, examining their underlying coordination and highlighting missing information and emerging new features of Polycomb-mediated transcriptional control.
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Affiliation(s)
- Simone Tamburri
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy; University of Milan, Department of Health Sciences, Via A. di Rudinì 8, 20142 Milan, Italy.
| | - Samantha Rustichelli
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Simona Amato
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Diego Pasini
- IEO, European Institute of Oncology IRCCS, Department of Experimental Oncology, Via Adamello 16, 20139 Milan, Italy; University of Milan, Department of Health Sciences, Via A. di Rudinì 8, 20142 Milan, Italy.
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2
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Yang JH, Hansen AS. Enhancer selectivity in space and time: from enhancer-promoter interactions to promoter activation. Nat Rev Mol Cell Biol 2024; 25:574-591. [PMID: 38413840 DOI: 10.1038/s41580-024-00710-6] [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: 01/30/2024] [Indexed: 02/29/2024]
Abstract
The primary regulators of metazoan gene expression are enhancers, originally functionally defined as DNA sequences that can activate transcription at promoters in an orientation-independent and distance-independent manner. Despite being crucial for gene regulation in animals, what mechanisms underlie enhancer selectivity for promoters, and more fundamentally, how enhancers interact with promoters and activate transcription, remain poorly understood. In this Review, we first discuss current models of enhancer-promoter interactions in space and time and how enhancers affect transcription activation. Next, we discuss different mechanisms that mediate enhancer selectivity, including repression, biochemical compatibility and regulation of 3D genome structure. Through 3D polymer simulations, we illustrate how the ability of 3D genome folding mechanisms to mediate enhancer selectivity strongly varies for different enhancer-promoter interaction mechanisms. Finally, we discuss how recent technical advances may provide new insights into mechanisms of enhancer-promoter interactions and how technical biases in methods such as Hi-C and Micro-C and imaging techniques may affect their interpretation.
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Affiliation(s)
- Jin H Yang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA.
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3
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Akilli N, Cheutin T, Cavalli G. Phase separation and inheritance of repressive chromatin domains. Curr Opin Genet Dev 2024; 86:102201. [PMID: 38701672 DOI: 10.1016/j.gde.2024.102201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/04/2024] [Accepted: 04/16/2024] [Indexed: 05/05/2024]
Abstract
Polycomb-associated chromatin and pericentromeric heterochromatin form genomic domains important for the epigenetic regulation of gene expression. Both Polycomb complexes and heterochromatin factors rely on 'read and write' mechanisms, which, on their own, are not sufficient to explain the formation and the maintenance of these epigenetic domains. Microscopy has revealed that they form specific nuclear compartments separated from the rest of the genome. Recently, some subunits of these molecular machineries have been shown to undergo phase separation, both in vitro and in vivo, suggesting that phase separation might play important roles in the formation and the function of these two kinds of repressive chromatin. In this review, we will present the recent advances in the field of facultative and constitutive heterochromatin formation and maintenance through phase separation.
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Affiliation(s)
- Nazli Akilli
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France. https://twitter.com/@sinmerank
| | - Thierry Cheutin
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France.
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4
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Guo JK, Blanco MR, Walkup WG, Bonesteele G, Urbinati CR, Banerjee AK, Chow A, Ettlin O, Strehle M, Peyda P, Amaya E, Trinh V, Guttman M. Denaturing purifications demonstrate that PRC2 and other widely reported chromatin proteins do not appear to bind directly to RNA in vivo. Mol Cell 2024; 84:1271-1289.e12. [PMID: 38387462 PMCID: PMC10997485 DOI: 10.1016/j.molcel.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/01/2023] [Accepted: 01/30/2024] [Indexed: 02/24/2024]
Abstract
Polycomb repressive complex 2 (PRC2) is reported to bind to many RNAs and has become a central player in reports of how long non-coding RNAs (lncRNAs) regulate gene expression. Yet, there is a growing discrepancy between the biochemical evidence supporting specific lncRNA-PRC2 interactions and functional evidence demonstrating that PRC2 is often dispensable for lncRNA function. Here, we revisit the evidence supporting RNA binding by PRC2 and show that many reported interactions may not occur in vivo. Using denaturing purification of in vivo crosslinked RNA-protein complexes in human and mouse cell lines, we observe a loss of detectable RNA binding to PRC2 and chromatin-associated proteins previously reported to bind RNA (CTCF, YY1, and others), despite accurately mapping bona fide RNA-binding sites across others (SPEN, TET2, and others). Taken together, these results argue for a critical re-evaluation of the broad role of RNA binding to orchestrate various chromatin regulatory mechanisms.
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Affiliation(s)
- Jimmy K Guo
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Mario R Blanco
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Ward G Walkup
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Grant Bonesteele
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Carl R Urbinati
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Biology, Loyola Marymount University, Los Angeles, CA 90045, USA
| | - Abhik K Banerjee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Amy Chow
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Olivia Ettlin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mackenzie Strehle
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Parham Peyda
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Enrique Amaya
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Vickie Trinh
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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5
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Seif E, Francis NJ. A Two-Step Mechanism for Creating Stable, Condensed Chromatin with the Polycomb Complex PRC1. Molecules 2024; 29:323. [PMID: 38257239 PMCID: PMC10821450 DOI: 10.3390/molecules29020323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
The Drosophila PRC1 complex regulates gene expression by modifying histone proteins and chromatin architecture. Two PRC1 subunits, PSC and Ph, are most implicated in chromatin architecture. In vitro, PRC1 compacts chromatin and inhibits transcription and nucleosome remodeling. The long disordered C-terminal region of PSC (PSC-CTR) is important for these activities, while Ph has little effect. In cells, Ph is important for condensate formation, long-range chromatin interactions, and gene regulation, and its polymerizing sterile alpha motif (SAM) is implicated in these activities. In vitro, truncated Ph containing the SAM and two other conserved domains (mini-Ph) undergoes phase separation with chromatin, suggesting a mechanism for SAM-dependent condensate formation in vivo. How the distinct activities of PSC and Ph on chromatin function together in PRC1 is not known. To address this question, we analyzed structures formed with large chromatin templates and PRC1 in vitro. PRC1 bridges chromatin into extensive fibrillar networks. Ph, its SAM, and SAM polymerization activity have little effect on these structures. Instead, the PSC-CTR controls their growth, and is sufficient for their formation. To understand how phase separation driven by Ph SAM intersects with the chromatin bridging activity of the PSC-CTR, we used mini-Ph to form condensates with chromatin and then challenged them with PRC1 lacking Ph (PRC1ΔPh). PRC1ΔPh converts mini-Ph chromatin condensates into clusters of small non-fusing condensates and bridged fibers. These condensates retain a high level of chromatin compaction and do not intermix. Thus, phase separation of chromatin by mini-Ph, followed by the action of the PSC-CTR, creates a unique chromatin organization with regions of high nucleosome density and extraordinary stability. We discuss how this coordinated sequential activity of two proteins found in the same complex may occur and the possible implications of stable chromatin architectures in maintaining transcription states.
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Affiliation(s)
- Elias Seif
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
| | - Nicole J. Francis
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montréal, QC H4A 3J1, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada
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6
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Chen F, Hou W, Yu X, Wu J, Li Z, Xu J, Deng Z, Chen G, Liu B, Yin X, Yu W, Zhang L, Xu G, Ji H, Liang C, Wang Z. CBX4 deletion promotes tumorigenesis under Kras G12D background by inducing genomic instability. Signal Transduct Target Ther 2023; 8:343. [PMID: 37696812 PMCID: PMC10495400 DOI: 10.1038/s41392-023-01623-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 08/03/2023] [Accepted: 08/22/2023] [Indexed: 09/13/2023] Open
Abstract
Chromobox protein homolog 4 (CBX4) is a component of the Polycomb group (PcG) multiprotein Polycomb repressive complexes 1 (PRC1), which is participated in several processes including growth, senescence, immunity, and tissue repair. CBX4 has been shown to have diverse, even opposite functions in different types of tissue and malignancy in previous studies. In this study, we found that CBX4 deletion promoted lung adenocarcinoma (LUAD) proliferation and progression in KrasG12D mutated background. In vitro, over 50% Cbx4L/L, KrasG12D mouse embryonic fibroblasts (MEFs) underwent apoptosis in the initial period after Adeno-Cre virus treatment, while a small portion of survival cells got increased proliferation and transformation abilities, which we called selected Cbx4-/-, KrasG12D cells. Karyotype analysis and RNA-seq data revealed chromosome instability and genome changes in selected Cbx4-/-, KrasG12D cells compared with KrasG12D cells. Further study showed that P15, P16 and other apoptosis-related genes were upregulated in the primary Cbx4-/-, KrasG12D cells due to chromosome instability, which led to the large population of cell apoptosis. In addition, multiple pathways including Hippo pathway and basal cell cancer-related signatures were altered in selected Cbx4-/-, KrasG12D cells, ultimately leading to cancer. We also found that low expression of CBX4 in LUAD was associated with poorer prognosis under Kras mutation background from the human clinical data. To sum up, CBX4 deletion causes genomic instability to induce tumorigenesis under KrasG12D background. Our study demonstrates that CBX4 plays an emerging role in tumorigenesis, which is of great importance in guiding the clinical treatment of lung adenocarcinoma.
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Affiliation(s)
- Fangzhen Chen
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China
| | - Wulei Hou
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, Fudan University, Shanghai, 200031, China
| | - Xiangtian Yu
- Clinical Research Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jing Wu
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China
| | - Zhengda Li
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China
| | - Jietian Xu
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China
| | - Zimu Deng
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Gaobin Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Bo Liu
- CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Xiaoxing Yin
- Department of General Surgery, Jing'an District Central Hospital of Shanghai, Fudan University, Shanghai, China
| | - Wei Yu
- Key Laboratory of Respiratory Disease, People's Hospital of Yangjiang, Yangjiang, Guangdong, China
| | - Lei Zhang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Guoliang Xu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Hongbin Ji
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Chunmin Liang
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China.
| | - Zuoyun Wang
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences and Shanghai Xuhui Central Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China.
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7
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Kramer HM, Cook DE, Seidl MF, Thomma BP. Epigenetic regulation of nuclear processes in fungal plant pathogens. PLoS Pathog 2023; 19:e1011525. [PMID: 37535497 PMCID: PMC10399791 DOI: 10.1371/journal.ppat.1011525] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023] Open
Abstract
Through the association of protein complexes to DNA, the eukaryotic nuclear genome is broadly organized into open euchromatin that is accessible for enzymes acting on DNA and condensed heterochromatin that is inaccessible. Chemical and physical alterations to chromatin may impact its organization and functionality and are therefore important regulators of nuclear processes. Studies in various fungal plant pathogens have uncovered an association between chromatin organization and expression of in planta-induced genes that are important for pathogenicity. This review discusses chromatin-based regulation mechanisms as determined in the fungal plant pathogen Verticillium dahliae and relates the importance of epigenetic transcriptional regulation and other nuclear processes more broadly in fungal plant pathogens.
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Affiliation(s)
- H. Martin Kramer
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - David E. Cook
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas, United States of America
| | - Michael F. Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Theoretical Biology & Bioinformatics, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Bart P.H.J. Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
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8
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Regulation of Polyhomeotic Condensates by Intrinsically Disordered Sequences That Affect Chromatin Binding. EPIGENOMES 2022; 6:epigenomes6040040. [PMID: 36412795 PMCID: PMC9680516 DOI: 10.3390/epigenomes6040040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
The Polycomb group (PcG) complex PRC1 localizes in the nucleus in condensed structures called Polycomb bodies. The PRC1 subunit Polyhomeotic (Ph) contains an oligomerizing sterile alpha motif (SAM) that is implicated in both PcG body formation and chromatin organization in Drosophila and mammalian cells. A truncated version of Ph containing the SAM (mini-Ph) forms phase-separated condensates with DNA or chromatin in vitro, suggesting that PcG bodies may form through SAM-driven phase separation. In cells, Ph forms multiple small condensates, while mini-Ph typically forms a single large nuclear condensate. We therefore hypothesized that sequences outside of mini-Ph, which are predicted to be intrinsically disordered, are required for proper condensate formation. We identified three distinct low-complexity regions in Ph based on sequence composition. We systematically tested the role of each of these sequences in Ph condensates using live imaging of transfected Drosophila S2 cells. Each sequence uniquely affected Ph SAM-dependent condensate size, number, and morphology, but the most dramatic effects occurred when the central, glutamine-rich intrinsically disordered region (IDR) was removed, which resulted in large Ph condensates. Like mini-Ph condensates, condensates lacking the glutamine-rich IDR excluded chromatin. Chromatin fractionation experiments indicated that the removal of the glutamine-rich IDR reduced chromatin binding and that the removal of either of the other IDRs increased chromatin binding. Our data suggest that all three IDRs, and functional interactions among them, regulate Ph condensate size and number. Our results can be explained by a model in which tight chromatin binding by Ph IDRs antagonizes Ph SAM-driven phase separation. Our observations highlight the complexity of regulation of biological condensates housed in single proteins.
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9
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Wang C, Solberg T, Maurer-Alcalá XX, Swart EC, Gao F, Nowacki M. A small RNA-guided PRC2 complex eliminates DNA as an extreme form of transposon silencing. Cell Rep 2022; 40:111263. [PMID: 36001962 PMCID: PMC10073204 DOI: 10.1016/j.celrep.2022.111263] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 06/27/2022] [Accepted: 08/04/2022] [Indexed: 01/04/2023] Open
Abstract
In animal germlines, transposons are silenced at the transcriptional or post-transcriptional level to prevent deleterious expression. Ciliates employ a more direct approach by physically eliminating transposons from their soma, utilizing piRNAs to recognize transposons and imprecisely excise them. Ancient, mutated transposons often do not require piRNAs and are precisely eliminated. Here, we characterize the Polycomb Repressive Complex 2 (PRC2) in Paramecium and demonstrate its involvement in the removal of transposons and transposon-derived DNA. Our results reveal a striking difference between the elimination of new and ancient transposons at the chromatin level and show that the complex may be guided by Piwi-bound small RNAs (sRNAs). We propose that imprecise elimination in ciliates originates from an ancient transposon silencing mechanism, much like in plants and metazoans, through sRNAs, repressive methylation marks, and heterochromatin formation. However, it is taken a step further by eliminating DNA as an extreme form of transposon silencing.
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Affiliation(s)
- Chundi Wang
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Therese Solberg
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland
| | - Xyrus X Maurer-Alcalá
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland; Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY 10024, USA
| | - Estienne C Swart
- Max Planck Institute for Biology, Max Planck Ring 5, 72076 Tuebingen, Germany
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (OUC), Ministry of Education, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.
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10
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Razin SV, Zhegalova IV, Kantidze OL. Domain Model of Eukaryotic Genome Organization: From DNA Loops Fixed on the Nuclear Matrix to TADs. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:667-680. [PMID: 36154886 DOI: 10.1134/s0006297922070082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 06/16/2023]
Abstract
The article reviews the development of ideas on the domain organization of eukaryotic genome, with special attention on the studies of DNA loops anchored to the nuclear matrix and their role in the emergence of the modern model of eukaryotic genome spatial organization. Critical analysis of results demonstrating that topologically associated chromatin domains are structural-functional blocks of the genome supports the notion that these blocks are fundamentally different from domains whose existence was proposed by the domain hypothesis of eukaryotic genome organization formulated in the 1980s. Based on the discussed evidence, it is concluded that the model postulating that eukaryotic genome is built from uniformly organized structural-functional blocks has proven to be untenable.
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Affiliation(s)
- Sergey V Razin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Irina V Zhegalova
- Skolkovo Institute of Science and Technology, Moscow, 121205, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia
- Kharkevich Institute for Information Transmission Problems, Moscow, 127051, Russia
| | - Omar L Kantidze
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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11
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Hillje R, Luzi L, Amatori S, Persico G, Casciaro F, Rusin M, Fanelli M, Pelicci P, Giorgio M. Time makes histone H3 modifications drift in mouse liver. Aging (Albany NY) 2022; 14:4959-4975. [PMID: 35687897 PMCID: PMC9271290 DOI: 10.18632/aging.204107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 05/19/2022] [Indexed: 11/30/2022]
Abstract
To detect the epigenetic drift of time passing, we determined the genome-wide distributions of mono- and tri-methylated lysine 4 and acetylated and tri-methylated lysine 27 of histone H3 in the livers of healthy 3, 6 and 12 months old C57BL/6 mice. The comparison of different age profiles of histone H3 marks revealed global redistribution of histone H3 modifications with time, in particular in intergenic regions and near transcription start sites, as well as altered correlation between the profiles of different histone modifications. Moreover, feeding mice with caloric restriction diet, a treatment known to retard aging, reduced the extent of changes occurring during the first year of life in these genomic regions.
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Affiliation(s)
- Roman Hillje
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy
| | - Lucilla Luzi
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy
| | - Stefano Amatori
- Department of Biomolecular Sciences, Molecular Pathology Lab, University of Urbino 'Carlo Bo', Fano 61032, Italy
| | - Giuseppe Persico
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy
| | - Francesca Casciaro
- Department of Biomedical Sciences, University of Padua, Padova 35131, Italy
| | - Martina Rusin
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy.,Department of Biomolecular Sciences, Molecular Pathology Lab, University of Urbino 'Carlo Bo', Fano 61032, Italy
| | - Mirco Fanelli
- Department of Biomolecular Sciences, Molecular Pathology Lab, University of Urbino 'Carlo Bo', Fano 61032, Italy
| | - Piergiuseppe Pelicci
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy.,Department of Oncology and Hemato-Oncology, University of Milan, Milano 20122, Italy
| | - Marco Giorgio
- Department of Experimental Oncology, IRCCS - European Institute of Oncology, Milano 20139, Italy.,Department of Biomedical Sciences, University of Padua, Padova 35131, Italy
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Abstract
Enhancers control the establishment of spatiotemporal gene expression patterns throughout development. Over the past decade, the development of new technologies has improved our capacity to link enhancers with their target genes based on their colocalization within the same topological domains. However, the mechanisms that regulate how enhancers specifically activate some genes but not others within a given domain remain unclear. In this Review, we discuss recent insights into the factors controlling enhancer specificity, including the genetic composition of enhancers and promoters, the linear and 3D distance between enhancers and their target genes, and cell-type specific chromatin landscapes. We also discuss how elucidating the molecular principles of enhancer specificity might help us to better understand and predict the pathological consequences of human genetic, epigenetic and structural variants.
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Affiliation(s)
- Tomás Pachano
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), CSIC/Universidad de Cantabria/SODERCAN, Albert Einstein 22, 39011 Santander, Spain
| | - Endika Haro
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), CSIC/Universidad de Cantabria/SODERCAN, Albert Einstein 22, 39011 Santander, Spain
| | - Alvaro Rada-Iglesias
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), CSIC/Universidad de Cantabria/SODERCAN, Albert Einstein 22, 39011 Santander, Spain
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13
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Thulabandu V, Nehila T, Ferguson JW, Atit RP. Dermal EZH2 orchestrates dermal differentiation and epidermal proliferation during murine skin development. Dev Biol 2021; 478:25-40. [PMID: 34166654 PMCID: PMC8384472 DOI: 10.1016/j.ydbio.2021.06.008] [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: 03/08/2021] [Revised: 05/28/2021] [Accepted: 06/18/2021] [Indexed: 10/21/2022]
Abstract
Skin development and patterning is dependent on factors that regulate the stepwise differentiation of dermal fibroblasts concomitant with dermal-epidermal reciprocal signaling, two processes that are poorly understood. Here we show that dermal EZH2, the methyltransferase enzyme of the epigenetic Polycomb Repressive Complex 2 (PRC2), is a new coordinator of both these processes. Dermal EZH2 activity is present during dermal fibroblast differentiation and is required for spatially restricting Wnt/β-catenin signaling to reinforce dermal fibroblast cell fate. Later in development, dermal EZH2 regulates the expression of reticular dermal markers and initiation of secondary hair follicles. Embryos lacking dermal Ezh2 have elevated epidermal proliferation and differentiation that can be rescued by small molecule inhibition of retinoic acid (RA) signaling. Together, our study reveals that dermal EZH2 is acting like a rheostat to control the levels of Wnt/β-catenin and RA signaling to impact fibroblast differentiation cell autonomously and epidermal keratinocyte development non-cell autonomously, respectively.
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Affiliation(s)
| | - Timothy Nehila
- Dept. of Biology, Case Western Reserve University, Cleveland, OH, USA
| | - James W Ferguson
- Dept. of Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Radhika P Atit
- Dept. of Biology, Case Western Reserve University, Cleveland, OH, USA; Dept. of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA; Dept. of Dermatology, Case Western Reserve University, Cleveland, OH, USA.
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14
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Moretti C, Stévant I, Ghavi-Helm Y. 3D genome organisation in Drosophila. Brief Funct Genomics 2021; 19:92-100. [PMID: 31796947 DOI: 10.1093/bfgp/elz029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/02/2019] [Accepted: 09/20/2019] [Indexed: 12/17/2022] Open
Abstract
Ever since Thomas Hunt Morgan's discovery of the chromosomal basis of inheritance by using Drosophila melanogaster as a model organism, the fruit fly has remained an essential model system in studies of genome biology, including chromatin organisation. Very much as in vertebrates, in Drosophila, the genome is organised in territories, compartments and topologically associating domains (TADs). However, these domains might be formed through a slightly different mechanism than in vertebrates due to the presence of a large and potentially redundant set of insulator proteins and the minor role of dCTCF in TAD boundary formation. Here, we review the different levels of chromatin organisation in Drosophila and discuss mechanisms and factors that might be involved in TAD formation. The dynamics of TADs and enhancer-promoter interactions in the context of transcription are covered in the light of currently conflicting results. Finally, we illustrate the value of polymer modelling approaches to infer the principles governing the three-dimensional organisation of the Drosophila genome.
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Affiliation(s)
- Charlotte Moretti
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
| | - Isabelle Stévant
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
| | - Yad Ghavi-Helm
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, 46 allée d'Italie F-69364 Lyon, France
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15
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Xiao Y, Yuan Y, Jimenez M, Soni N, Yadlapalli S. Clock proteins regulate spatiotemporal organization of clock genes to control circadian rhythms. Proc Natl Acad Sci U S A 2021; 118:e2019756118. [PMID: 34234015 PMCID: PMC8285898 DOI: 10.1073/pnas.2019756118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Circadian clocks regulate ∼24-h oscillations in gene expression, behavior, and physiology. While the genetic and molecular mechanisms of circadian rhythms are well characterized, what remains poorly understood are the intracellular dynamics of circadian clock components and how they affect circadian rhythms. Here, we elucidate how spatiotemporal organization and dynamics of core clock proteins and genes affect circadian rhythms in Drosophila clock neurons. Using high-resolution imaging and DNA-fluorescence in situ hybridization techniques, we demonstrate that Drosophila clock proteins (PERIOD and CLOCK) are organized into a few discrete foci at the nuclear envelope during the circadian repression phase and play an important role in the subnuclear localization of core clock genes to control circadian rhythms. Specifically, we show that core clock genes, period and timeless, are positioned close to the nuclear periphery by the PERIOD protein specifically during the repression phase, suggesting that subnuclear localization of core clock genes might play a key role in their rhythmic gene expression. Finally, we show that loss of Lamin B receptor, a nuclear envelope protein, leads to disruption of PER foci and per gene peripheral localization and results in circadian rhythm defects. These results demonstrate that clock proteins play a hitherto unexpected role in the subnuclear reorganization of core clock genes to control circadian rhythms, revealing how clocks function at the subcellular level. Our results further suggest that clock protein foci might regulate dynamic clustering and spatial reorganization of clock-regulated genes over the repression phase to control circadian rhythms in behavior and physiology.
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Affiliation(s)
- Yangbo Xiao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ye Yuan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109
| | - Mariana Jimenez
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Neeraj Soni
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Swathi Yadlapalli
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109;
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16
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Huang Y, Sicar S, Ramirez-Prado JS, Manza-Mianza D, Antunez-Sanchez J, Brik-Chaouche R, Rodriguez-Granados NY, An J, Bergounioux C, Mahfouz MM, Hirt H, Crespi M, Concia L, Barneche F, Amiard S, Probst AV, Gutierrez-Marcos J, Ariel F, Raynaud C, Latrasse D, Benhamed M. Polycomb-dependent differential chromatin compartmentalization determines gene coregulation in Arabidopsis. Genome Res 2021; 31:1230-1244. [PMID: 34083408 PMCID: PMC8256866 DOI: 10.1101/gr.273771.120] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 05/20/2021] [Indexed: 11/24/2022]
Abstract
In animals, distant H3K27me3-marked Polycomb targets can establish physical interactions forming repressive chromatin hubs. In plants, growing evidence suggests that H3K27me3 acts directly or indirectly to regulate chromatin interactions, although how this histone modification modulates 3D chromatin architecture remains elusive. To decipher the impact of the dynamic deposition of H3K27me3 on the Arabidopsis thaliana nuclear interactome, we combined genetics, transcriptomics, and several 3D epigenomic approaches. By analyzing mutants defective for histone H3K27 methylation or demethylation, we uncovered the crucial role of this chromatin mark in short- and previously unnoticed long-range chromatin loop formation. We found that a reduction in H3K27me3 levels led to a decrease in the interactions within Polycomb-associated repressive domains. Regions with lower H3K27me3 levels in the H3K27 methyltransferase clf mutant established new interactions with regions marked with H3K9ac, a histone modification associated with active transcription, indicating that a reduction in H3K27me3 levels induces a global reconfiguration of chromatin architecture. Altogether, our results reveal that the 3D genome organization is tightly linked to reversible histone modifications that govern chromatin interactions. Consequently, nuclear organization dynamics shapes the transcriptional reprogramming during plant development and places H3K27me3 as a key feature in the coregulation of distant genes.
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Affiliation(s)
- Ying Huang
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Sanchari Sicar
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Juan S Ramirez-Prado
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Deborah Manza-Mianza
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | | | - Rim Brik-Chaouche
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Natalia Y Rodriguez-Granados
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Jing An
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Catherine Bergounioux
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Magdy M Mahfouz
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Heribert Hirt
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Martin Crespi
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Lorenzo Concia
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), ENS, CNRS UMR8197, INSERM U1024, PSL Research University, 75005, Paris, France
| | - Fredy Barneche
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), ENS, CNRS UMR8197, INSERM U1024, PSL Research University, 75005, Paris, France
| | - Simon Amiard
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | - Aline V Probst
- GReD, Université Clermont Auvergne, CNRS, INSERM, BP 38, 63001, Clermont-Ferrand, France
| | | | - Federico Ariel
- Instituto de Agrobiotecnología del Litoral, CONICET, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina
| | - Cécile Raynaud
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - David Latrasse
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
| | - Moussa Benhamed
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
- Université de Paris, Institute of Plant Sciences Paris-Saclay (IPS2), F-75006 Paris, France
- Institut Universitaire de France (IUF)
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17
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Wang M, Li Z, Zhang Y, Zhang Y, Xie Y, Ye L, Zhuang Y, Lin K, Zhao F, Guo J, Teng W, Zhang W, Tong Y, Xue Y, Zhang Y. An atlas of wheat epigenetic regulatory elements reveals subgenome divergence in the regulation of development and stress responses. THE PLANT CELL 2021; 33:865-881. [PMID: 33594406 PMCID: PMC8226296 DOI: 10.1093/plcell/koab028] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/25/2021] [Indexed: 05/22/2023]
Abstract
Wheat (Triticum aestivum) has a large allohexaploid genome. Subgenome-divergent regulation contributed to genome plasticity and the domestication of polyploid wheat. However, the specificity encoded in the wheat genome determining subgenome-divergent spatio-temporal regulation has been largely unexplored. The considerable size and complexity of the genome are major obstacles to dissecting the regulatory specificity. Here, we compared the epigenomes and transcriptomes from a large set of samples under diverse developmental and environmental conditions. Thousands of distal epigenetic regulatory elements (distal-epiREs) were specifically linked to their target promoters with coordinated epigenomic changes. We revealed that subgenome-divergent activity of homologous regulatory elements is affected by specific epigenetic signatures. Subgenome-divergent epiRE regulation of tissue specificity is associated with dynamic modulation of H3K27me3 mediated by Polycomb complex and demethylases. Furthermore, quantitative epigenomic approaches detected key stress responsive cis- and trans-acting factors validated by DNA Affinity Purification and sequencing, and demonstrated the coordinated interplay between epiRE sequence contexts, epigenetic factors, and transcription factors in regulating subgenome divergent transcriptional responses to external changes. Together, this study provides a wealth of resources for elucidating the epiRE regulomics and subgenome-divergent regulation in hexaploid wheat, and gives new clues for interpreting genetic and epigenetic interplay in regulating the benefits of polyploid wheat.
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Affiliation(s)
| | | | | | | | - Yilin Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Luhuan Ye
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yili Zhuang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Kande Lin
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Fei Zhao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jingyu Guo
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- Henan University, School of Life Science, Kaifeng, Henan 457000, China
| | - Wan Teng
- University of the Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, and The Innovation Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenli Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Yiping Tong
- University of the Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, and The Innovation Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
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18
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Spatial modeling of biological patterns shows multiscale organization of Arabidopsis thaliana heterochromatin. Sci Rep 2021; 11:323. [PMID: 33431919 PMCID: PMC7801681 DOI: 10.1038/s41598-020-79158-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/01/2020] [Indexed: 01/29/2023] Open
Abstract
The spatial organization in the cell nucleus is tightly linked to genome functions such as gene regulation. Similarly, specific spatial arrangements of biological components such as macromolecular complexes, organelles and cells are involved in many biological functions. Spatial interactions among elementary components of biological systems define their relative positioning and are key determinants of spatial patterns. However, biological variability and the lack of appropriate spatial statistical methods and models limit our current ability to analyze these interactions. Here, we developed a framework to dissect spatial interactions and organization principles by combining unbiased statistical tests, multiple spatial descriptors and new spatial models. We used plant constitutive heterochromatin as a model system to demonstrate the potential of our framework. Our results challenge the common view of a peripheral organization of chromocenters, showing that chromocenters are arranged along both radial and lateral directions in the nuclear space and obey a multiscale organization with scale-dependent antagonistic effects. The proposed generic framework will be useful to identify determinants of spatial organizations and to question their interplay with biological functions.
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19
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Penagos-Puig A, Furlan-Magaril M. Heterochromatin as an Important Driver of Genome Organization. Front Cell Dev Biol 2020; 8:579137. [PMID: 33072761 PMCID: PMC7530337 DOI: 10.3389/fcell.2020.579137] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Heterochromatin is a constituent of eukaryotic genomes with functions spanning from gene expression silencing to constraining DNA replication and repair. Inside the nucleus, heterochromatin segregates spatially from euchromatin and is localized preferentially toward the nuclear periphery and surrounding the nucleolus. Despite being an abundant nuclear compartment, little is known about how heterochromatin regulates and participates in the mechanisms driving genome organization. Here, we review pioneer and recent evidence that explores the functional role of heterochromatin in the formation of distinct chromatin compartments and how failure of the molecular mechanisms forming heterochromatin leads to disarray of genome conformation and disease.
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Affiliation(s)
- Andrés Penagos-Puig
- Department of Molecular Genetics, Institute of Cellular Physiology, National Autonomous University of Mexico, Mexico City, Mexico
| | - Mayra Furlan-Magaril
- Department of Molecular Genetics, Institute of Cellular Physiology, National Autonomous University of Mexico, Mexico City, Mexico
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20
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Huang Y, Rodriguez-Granados NY, Latrasse D, Raynaud C, Benhamed M, Ramirez-Prado JS. The matrix revolutions: towards the decoding of the plant chromatin three-dimensional reality. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5129-5147. [PMID: 32639553 DOI: 10.1093/jxb/eraa322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
In recent years, we have witnessed a significant increase in studies addressing the three-dimensional (3D) chromatin organization of the plant nucleus. Important advances in chromatin conformation capture (3C)-derived and related techniques have allowed the exploration of the nuclear topology of plants with large and complex genomes, including various crops. In addition, the increase in their resolution has permitted the depiction of chromatin compartmentalization and interactions at the gene scale. These studies have revealed the highly complex mechanisms governing plant nuclear architecture and the remarkable knowledge gaps in this field. Here we discuss the state-of-the-art in plant chromosome architecture, including our knowledge of the hierarchical organization of the genome in 3D space and regarding other nuclear components. Furthermore, we highlight the existence in plants of topologically associated domain (TAD)-like structures that display striking differences from their mammalian counterparts, proposing the concept of ICONS-intergenic condensed spacers. Similarly, we explore recent advances in the study of chromatin loops and R-loops, and their implication in the regulation of gene activity. Finally, we address the impact that polyploidization has had on the chromatin topology of modern crops, and how this is related to phenomena such as subgenome dominance and biased gene retention in these organisms.
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Affiliation(s)
- Ying Huang
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - Natalia Yaneth Rodriguez-Granados
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - David Latrasse
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - Cecile Raynaud
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
| | - Moussa Benhamed
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
- Institut Universitaire de France (IUF), France
| | - Juan Sebastian Ramirez-Prado
- Institute of Plant Sciences Paris of Saclay (IPS2), UMR 9213/UMR1403, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Orsay, France
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21
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Santos AP, Gaudin V, Mozgová I, Pontvianne F, Schubert D, Tek AL, Dvořáčková M, Liu C, Fransz P, Rosa S, Farrona S. Tidying-up the plant nuclear space: domains, functions, and dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5160-5178. [PMID: 32556244 PMCID: PMC8604271 DOI: 10.1093/jxb/eraa282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/12/2020] [Indexed: 05/07/2023]
Abstract
Understanding how the packaging of chromatin in the nucleus is regulated and organized to guide complex cellular and developmental programmes, as well as responses to environmental cues is a major question in biology. Technological advances have allowed remarkable progress within this field over the last years. However, we still know very little about how the 3D genome organization within the cell nucleus contributes to the regulation of gene expression. The nuclear space is compartmentalized in several domains such as the nucleolus, chromocentres, telomeres, protein bodies, and the nuclear periphery without the presence of a membrane around these domains. The role of these domains and their possible impact on nuclear activities is currently under intense investigation. In this review, we discuss new data from research in plants that clarify functional links between the organization of different nuclear domains and plant genome function with an emphasis on the potential of this organization for gene regulation.
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Affiliation(s)
- Ana Paula Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova
de Lisboa, Oeiras, Portugal
| | - Valérie Gaudin
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université
Paris-Saclay, Versailles, France
| | - Iva Mozgová
- Biology Centre of the Czech Academy of Sciences, České
Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České
Budějovice, Czech Republic
| | - Frédéric Pontvianne
- CNRS, Laboratoire Génome et Développement des Plantes (LGDP), Université de
Perpignan Via Domitia, Perpignan, France
| | - Daniel Schubert
- Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Ahmet L Tek
- Agricultural Genetic Engineering Department, Niğde Ömer Halisdemir
University, Niğde, Turkey
| | | | - Chang Liu
- Center for Plant Molecular Biology (ZMBP), University of
Tübingen, Tübingen, Germany
- Institute of Biology, University of Hohenheim, Stuttgart,
Germany
| | - Paul Fransz
- University of Amsterdam, Amsterdam, The
Netherlands
| | - Stefanie Rosa
- Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Farrona
- Plant and AgriBiosciences Centre, Ryan Institute, NUI Galway,
Galway, Ireland
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22
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Heurteau A, Perrois C, Depierre D, Fosseprez O, Humbert J, Schaak S, Cuvier O. Insulator-based loops mediate the spreading of H3K27me3 over distant micro-domains repressing euchromatin genes. Genome Biol 2020; 21:193. [PMID: 32746892 PMCID: PMC7397589 DOI: 10.1186/s13059-020-02106-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 07/14/2020] [Indexed: 12/16/2022] Open
Abstract
Abstract
Background
Chromosomes are subdivided spatially to delimit long-range interactions into topologically associating domains (TADs). TADs are often flanked by chromatin insulators and transcription units that may participate in such demarcation. Remarkably, single-cell Drosophila TAD units correspond to dynamic heterochromatin nano-compartments that can self-assemble. The influence of insulators on such dynamic compartmentalization remains unclear. Moreover, to what extent heterochromatin domains are fully compartmentalized away from active genes remains unclear from Drosophila to human.
Results
Here, we identify H3K27me3 micro-domains genome-wide in Drosophila, which are attributed to the three-dimensional spreading of heterochromatin marks into euchromatin. Whereas depletion of insulator proteins increases H3K27me3 spreading locally, across heterochromatin borders, it concomitantly decreases H3K27me3 levels at distant micro-domains discrete sites. Quantifying long-range interactions suggests that random interactions between heterochromatin TADs and neighbor euchromatin cannot predict the presence of micro-domains, arguing against the hypothesis that they reflect defects in self-folding or in insulating repressive TADs. Rather, micro-domains are predicted by specific long-range interactions with the TAD borders bound by insulator proteins and co-factors required for looping. Accordingly, H3K27me3 spreading to distant sites is impaired by insulator mutants that compromise recruitment of looping co-factors. Both depletions and insulator mutants significantly reduce H3K27me3 micro-domains, deregulating the flanking genes.
Conclusions
Our data highlight a new regulatory mode of H3K27me3 by insulator-based long-range interactions controlling distant euchromatic genes.
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Affiliation(s)
- Alexandre Heurteau
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
| | - Charlène Perrois
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
| | - David Depierre
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
| | - Olivier Fosseprez
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
| | - Jonathan Humbert
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
- St. Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Centre Hospitalier Universitaire de Québec City, Quebec, QC, G1R 3S3, Canada
| | - Stéphane Schaak
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France
| | - Olivier Cuvier
- Chromatin Dynamics and Cell Proliferation, Center of Integrative Biology (CBI), Laboratoire de Biologie Moléculaire Eucaryote (LBME), CNRS, Université Fédérale Paul Sabatier de Toulouse (UPS), F-31000, Toulouse, France.
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23
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RNA is essential for PRC2 chromatin occupancy and function in human pluripotent stem cells. Nat Genet 2020; 52:931-938. [PMID: 32632336 DOI: 10.1038/s41588-020-0662-x] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/08/2020] [Indexed: 12/11/2022]
Abstract
Many chromatin-binding proteins and protein complexes that regulate transcription also bind RNA. One of these, Polycomb repressive complex 2 (PRC2), deposits the H3K27me3 mark of facultative heterochromatin and is required for stem cell differentiation. PRC2 binds RNAs broadly in vivo and in vitro. Yet, the biological importance of this RNA binding remains unsettled. Here, we tackle this question in human induced pluripotent stem cells by using multiple complementary approaches. Perturbation of RNA-PRC2 interaction by RNase A, by a chemical inhibitor of transcription or by an RNA-binding-defective mutant all disrupted PRC2 chromatin occupancy and localization genome wide. The physiological relevance of PRC2-RNA interactions is further underscored by a cardiomyocyte differentiation defect upon genetic disruption. We conclude that PRC2 requires RNA binding for chromatin localization in human pluripotent stem cells and in turn for defining cellular state.
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24
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Pachano T, Crispatzu G, Rada-Iglesias A. Polycomb proteins as organizers of 3D genome architecture in embryonic stem cells. Brief Funct Genomics 2020; 18:358-366. [PMID: 31673701 DOI: 10.1093/bfgp/elz022] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/14/2019] [Accepted: 08/22/2019] [Indexed: 12/29/2022] Open
Abstract
Polycomb group proteins (PcGs) control the epigenetic and transcriptional state of developmental genes and regulatory elements during mammalian embryogenesis. Moreover, PcGs can also contribute to 3D genome organization, adding an additional layer of complexity to their regulatory functions. Understanding the mechanistic basis and the dynamics of PcG-dependent chromatin structures will help us untangle the full complexity of PcG function during development. Since most studies concerning the 3D organization of PcG-bound chromatin in mammals have been performed in embryonic stem cells (ESCs), here we will focus on this cell type characterized by its unique self-renewal and pluripotency properties. More specifically, we will highlight recent findings and discuss open questions regarding how PcG-dependent changes in 3D chromatin architecture control gene expression, cellular identity and differentiation potential in ESCs. We believe that this can serve to illustrate the diverse regulatory mechanisms by which PcG proteins control the proper execution of gene expression programs during mammalian embryogenesis.
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Affiliation(s)
- Tomas Pachano
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany
| | - Giuliano Crispatzu
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany.,Department II of Internal Medicine, University Hospital Cologne, Germany
| | - Alvaro Rada-Iglesias
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany.,Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany.,Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), University of Cantabria, Spain
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25
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Epigenomic analysis of gastrulation identifies a unique chromatin state for primed pluripotency. Nat Genet 2019; 52:95-105. [PMID: 31844322 DOI: 10.1038/s41588-019-0545-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022]
Abstract
Around implantation, the epiblast (Epi) transits from naïve to primed pluripotency, before giving rise to the three germ layers. How chromatin is reconfigured during this developmental window remains poorly understood. We performed a genome-wide investigation of chromatin landscapes during this period. We find that enhancers in ectoderm are already pre-accessible in embryonic day 6.5 (E6.5) Epi when cells enter a primed pluripotent state. Unexpectedly, strong trimethylation of histone H3 at lysine 4 (H3K4me3) emerges at developmental gene promoters in E6.5 Epi and positively correlates with H3K27me3, thus establishing bivalency. These genes also show enhanced spatial interactions. Both the strong bivalency and spatial clustering are virtually absent in preimplantation embryos and are markedly reduced in fate-committed lineages. Finally, we show that KMT2B is essential for establishing bivalent H3K4me3 at E6.5 but becomes partially dispensable later. Its deficiency leads to impaired activation of developmental genes and subsequent embryonic lethality. Thus, our data characterize lineage-specific chromatin reconfiguration and a unique chromatin state for primed pluripotency.
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26
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Bredesen BA, Rehmsmeier M. DNA sequence models of genome-wide Drosophila melanogaster Polycomb binding sites improve generalization to independent Polycomb Response Elements. Nucleic Acids Res 2019; 47:7781-7797. [PMID: 31340029 PMCID: PMC6735708 DOI: 10.1093/nar/gkz617] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/01/2019] [Accepted: 07/11/2019] [Indexed: 12/12/2022] Open
Abstract
Polycomb Response Elements (PREs) are cis-regulatory DNA elements that maintain gene transcription states through DNA replication and mitosis. PREs have little sequence similarity, but are enriched in a number of sequence motifs. Previous methods for modelling Drosophila melanogaster PRE sequences (PREdictor and EpiPredictor) have used a set of 7 motifs and a training set of 12 PREs and 16-23 non-PREs. Advances in experimental methods for mapping chromatin binding factors and modifications has led to the publication of several genome-wide sets of Polycomb targets. In addition to the seven motifs previously used, PREs are enriched in the GTGT motif, recently associated with the sequence-specific DNA binding protein Combgap. We investigated whether models trained on genome-wide Polycomb sites generalize to independent PREs when trained with control sequences generated by naive PRE models and including the GTGT motif. We also developed a new PRE predictor: SVM-MOCCA. Training PRE predictors with genome-wide experimental data improves generalization to independent data, and SVM-MOCCA predicts the majority of PREs in three independent experimental sets. We present 2908 candidate PREs enriched in sequence and chromatin signatures. 2412 of these are also enriched in H3K4me1, a mark of Trithorax activated chromatin, suggesting that PREs/TREs have a common sequence code.
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Affiliation(s)
- Bjørn André Bredesen
- Computational Biology Unit, Department of Informatics, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway
| | - Marc Rehmsmeier
- Computational Biology Unit, Department of Informatics, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway.,Integrated Research Institute (IRI) for the Life Sciences and Department of Biology, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany
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27
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Gozalo A, Duke A, Lan Y, Pascual-Garcia P, Talamas JA, Nguyen SC, Shah PP, Jain R, Joyce EF, Capelson M. Core Components of the Nuclear Pore Bind Distinct States of Chromatin and Contribute to Polycomb Repression. Mol Cell 2019; 77:67-81.e7. [PMID: 31784359 DOI: 10.1016/j.molcel.2019.10.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/04/2019] [Accepted: 10/11/2019] [Indexed: 12/15/2022]
Abstract
Interactions between the genome and the nuclear pore complex (NPC) have been implicated in multiple gene regulatory processes, but the underlying logic of these interactions remains poorly defined. Here, we report high-resolution chromatin binding maps of two core components of the NPC, Nup107 and Nup93, in Drosophila cells. Our investigation uncovered differential binding of these NPC subunits, where Nup107 preferentially targets active genes while Nup93 associates primarily with Polycomb-silenced regions. Comparison to Lamin-associated domains (LADs) revealed that NPC binding sites can be found within LADs, demonstrating a linear binding of the genome along the nuclear envelope. Importantly, we identified a functional role of Nup93 in silencing of Polycomb target genes and in spatial folding of Polycomb domains. Our findings lend to a model where different nuclear pores bind different types of chromatin via interactions with specific NPC sub-complexes, and a subset of Polycomb domains is stabilized by interactions with Nup93.
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Affiliation(s)
- Alejandro Gozalo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ashley Duke
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yemin Lan
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pau Pascual-Garcia
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jessica A Talamas
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Son C Nguyen
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Parisha P Shah
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rajan Jain
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric F Joyce
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maya Capelson
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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28
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Cheutin T, Cavalli G. The multiscale effects of polycomb mechanisms on 3D chromatin folding. Crit Rev Biochem Mol Biol 2019; 54:399-417. [PMID: 31698957 DOI: 10.1080/10409238.2019.1679082] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 12/30/2022]
Abstract
Polycomb group (PcG) proteins silence master regulatory genes required to properly confer cell identity during the development of both Drosophila and mammals. They may act through chromatin compaction and higher-order folding of chromatin inside the cell nucleus. During the last decade, analysis on interphase chromosome architecture discovered self-interacting regions named topologically associated domains (TADs). TADs result from the 3D chromatin folding of a succession of transcribed and repressed epigenomic domains and from loop extrusion mediated by cohesin/CTCF in mammals. Polycomb silenced chromatin constitutes one type of repressed epigenomic domains which form compacted nano-compartments inside cell nuclei. Recruitment of canonical PcG proteins on chromatin relies on initial binding to discrete elements and further spreading into large chromatin domains covered with H3K27me3. Some of these discrete elements have a bivalent nature both in mammals and Drosophila and are dynamically regulated during development. Loops can occur between them, suggesting that their interaction plays both functional and structural roles. Formation of large chromatin domains covered by H3K27me3 seems crucial for PcG silencing and PcG proteins might exert their function through compaction of these domains in both mammals and flies, rather than by directly controlling the nucleosomal accessibility of discrete regulatory elements. In addition, PcG chromatin domains interact over long genomic distances, shaping a higher-order chromatin network. Therefore, PcG silencing might rely on multiscale chromatin folding to maintain cell identity during differentiation.
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Affiliation(s)
- Thierry Cheutin
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France
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29
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Żylicz JJ, Bousard A, Žumer K, Dossin F, Mohammad E, da Rocha ST, Schwalb B, Syx L, Dingli F, Loew D, Cramer P, Heard E. The Implication of Early Chromatin Changes in X Chromosome Inactivation. Cell 2018; 176:182-197.e23. [PMID: 30595450 PMCID: PMC6333919 DOI: 10.1016/j.cell.2018.11.041] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/20/2018] [Accepted: 11/26/2018] [Indexed: 12/24/2022]
Abstract
During development, the precise relationships between transcription and chromatin modifications often remain unclear. We use the X chromosome inactivation (XCI) paradigm to explore the implication of chromatin changes in gene silencing. Using female mouse embryonic stem cells, we initiate XCI by inducing Xist and then monitor the temporal changes in transcription and chromatin by allele-specific profiling. This reveals histone deacetylation and H2AK119 ubiquitination as the earliest chromatin alterations during XCI. We show that HDAC3 is pre-bound on the X chromosome and that, upon Xist coating, its activity is required for efficient gene silencing. We also reveal that first PRC1-associated H2AK119Ub and then PRC2-associated H3K27me3 accumulate initially at large intergenic domains that can then spread into genes only in the context of histone deacetylation and gene silencing. Our results reveal the hierarchy of chromatin events during the initiation of XCI and identify key roles for chromatin in the early steps of transcriptional silencing.
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Affiliation(s)
- Jan Jakub Żylicz
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 75005 Paris, France; University of Cambridge, Department of Physiology, Development and Neuroscience, Cambridge CB2 3EG, UK
| | - Aurélie Bousard
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 75005 Paris, France
| | - Kristina Žumer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, 37077 Göttingen, Germany
| | - Francois Dossin
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 75005 Paris, France
| | - Eusra Mohammad
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, 37077 Göttingen, Germany
| | - Simão Teixeira da Rocha
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Björn Schwalb
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, 37077 Göttingen, Germany
| | - Laurène Syx
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 75005 Paris, France
| | - Florent Dingli
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, Paris 75248 Cedex 05, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, Paris 75248 Cedex 05, France
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, 37077 Göttingen, Germany
| | - Edith Heard
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, UPMC Paris-Sorbonne, 75005 Paris, France.
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30
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Cheutin T, Cavalli G. Loss of PRC1 induces higher-order opening of Hox loci independently of transcription during Drosophila embryogenesis. Nat Commun 2018; 9:3898. [PMID: 30254245 PMCID: PMC6156336 DOI: 10.1038/s41467-018-05945-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 07/30/2018] [Indexed: 12/14/2022] Open
Abstract
Polycomb-group proteins are conserved chromatin factors that maintain the silencing of key developmental genes, notably the Hox gene clusters, outside of their expression domains. Depletion of Polycomb repressive complex 1 (PRC1) proteins typically results in chromatin unfolding, as well as ectopic transcription. To disentangle these two phenomena, here we analyze the temporal function of two PRC1 proteins, Polyhomeotic (Ph) and Polycomb (Pc), on Hox gene clusters during Drosophila embryogenesis. We show that the absence of Ph or Pc affects the higher-order chromatin folding of Hox clusters prior to ectopic Hox gene transcription, demonstrating that PRC1 primary function during early embryogenesis is to compact its target chromatin. Moreover, the differential effects of Ph and Pc on Hox cluster folding match the differences in ectopic Hox gene expression observed in these two mutants. Our data suggest that PRC1 maintains gene silencing by folding chromatin domains and impose architectural layer to gene regulation. Loss of Polycomb repressive complex 1 (PRC1) proteins usually results in both chromatin unfolding and ectopic transcription. Here, the authors analyze the temporal function of two PRC1 proteins during Drosophila embryogenesis and provide evidence that PRC1 maintains gene silencing by folding chromatin domains.
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Affiliation(s)
- Thierry Cheutin
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France.
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France.
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31
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Polycomb-Dependent Chromatin Looping Contributes to Gene Silencing during Drosophila Development. Mol Cell 2018; 71:73-88.e5. [DOI: 10.1016/j.molcel.2018.05.032] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/12/2018] [Accepted: 05/24/2018] [Indexed: 01/21/2023]
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32
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33
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Kundu S, Ji F, Sunwoo H, Jain G, Lee JT, Sadreyev RI, Dekker J, Kingston RE. Polycomb Repressive Complex 1 Generates Discrete Compacted Domains that Change during Differentiation. Mol Cell 2017; 65:432-446.e5. [PMID: 28157505 DOI: 10.1016/j.molcel.2017.01.009] [Citation(s) in RCA: 221] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 11/08/2016] [Accepted: 01/05/2017] [Indexed: 12/27/2022]
Abstract
Master regulatory genes require stable silencing by the polycomb group (PcG) to prevent misexpression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in ESCs and neural progenitors using 5C and super-resolution microscopy. The genomic loci of repressed PcG targets formed discrete, small (20-140 Kb) domains of tight interaction that corresponded to locations bound by canonical polycomb repressive complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1 and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in size and boundary characteristics. These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher-order structure.
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Affiliation(s)
- Sharmistha Kundu
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Fei Ji
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hongjae Sunwoo
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Gaurav Jain
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Job Dekker
- Howard Hughes Medical Institute, Boston, MA 02115, USA; Program in Systems Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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34
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Buzas DM. Capturing Environmental Plant Memories in DNA, with a Little Help from Chromatin. PLANT & CELL PHYSIOLOGY 2017; 58:1302-1312. [PMID: 28961992 DOI: 10.1093/pcp/pcx092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/28/2017] [Indexed: 05/11/2023]
Abstract
Plants are eukaryotes living mostly immotile in harsh environments. On occasion, it is beneficial for their survival to maintain a transcriptional response to an environmental stress longer than the stress lasts (transcriptional memory) and even to reiterate such a response more quickly or more strongly when the same stress is re-encountered (priming memory). In eukaryotes, transcription takes place in the context of chromatin, the packaging material of DNA. Chromatin regulation is often invoked when it comes to environmental transcriptional and priming memory in plants, but rarely chromatin-based regulation can be accurately assigned to a given aspect of transcription in vivo. The conserved eukaryotic chromatin-modifying system Polycomb/Trithorax can support both long-term stability and flexibility of gene expression in Drosophila. The main principles of Polycomb/Trithorax regulation will be outlined and illustrated with the best-studied case of environmental memory from Arabidopsis. Despite being complex, the Polycomb/Trithorax system relies on experimentally tractable elements in the form of DNA, termed Polycomb/Trithorax Responsive Elements. PREs/TREs are essentially memory DNA elements. Here, relevant information to identify PRE/TRE-like elements in plants is highlighted. Examples of priming memory in plants are discussed in relation to the first two reported putative memory DNA elements. Arguably, similar cases from plants can be conducive in dissecting the contribution of DNA-based from chromatin-based regulation of transcription, when two types of DNA elements are defined: those representing binding sites for the transcription factors determining the environmental response and those controlling memory by regulating chromatin modification dynamics, ultimately maintaining the corresponding transcriptional state.
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Affiliation(s)
- Diana Mihaela Buzas
- Life and Environmental Sciences and Gene Research Centre, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan
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35
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Du J, Zhang J, He T, Li Y, Su Y, Tie F, Liu M, Harte PJ, Zhu AJ. Stuxnet Facilitates the Degradation of Polycomb Protein during Development. Dev Cell 2017; 37:507-19. [PMID: 27326929 DOI: 10.1016/j.devcel.2016.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/29/2016] [Accepted: 05/18/2016] [Indexed: 10/21/2022]
Abstract
Polycomb-group (PcG) proteins function to ensure correct deployment of developmental programs by epigenetically repressing target gene expression. Despite the importance, few studies have been focused on the regulation of PcG activity itself. Here, we report a Drosophila gene, stuxnet (stx), that controls Pc protein stability. We find that heightened stx activity leads to homeotic transformation, reduced Pc activity, and de-repression of PcG targets. Conversely, stx mutants, which can be rescued by decreased Pc expression, display developmental defects resembling hyperactivation of Pc. Our biochemical analyses provide a mechanistic basis for the interaction between stx and Pc; Stx facilitates Pc degradation in the proteasome, independent of ubiquitin modification. Furthermore, this mode of regulation is conserved in vertebrates. Mouse stx promotes degradation of Cbx4, an orthologous Pc protein, in vertebrate cells and induces homeotic transformation in Drosophila. Our results highlight an evolutionarily conserved mechanism of regulated protein degradation on PcG homeostasis and epigenetic activity.
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Affiliation(s)
- Juan Du
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Junzheng Zhang
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Tao He
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yajuan Li
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ying Su
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Feng Tie
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Min Liu
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Peter J Harte
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alan Jian Zhu
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
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36
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Three-Dimensional Genome Organization and Function in Drosophila. Genetics 2017; 205:5-24. [PMID: 28049701 PMCID: PMC5223523 DOI: 10.1534/genetics.115.185132] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/15/2016] [Indexed: 12/18/2022] Open
Abstract
Understanding how the metazoan genome is used during development and cell differentiation is one of the major challenges in the postgenomic era. Early studies in Drosophila suggested that three-dimensional (3D) chromosome organization plays important regulatory roles in this process and recent technological advances started to reveal connections at the molecular level. Here we will consider general features of the architectural organization of the Drosophila genome, providing historical perspective and insights from recent work. We will compare the linear and spatial segmentation of the fly genome and focus on the two key regulators of genome architecture: insulator components and Polycomb group proteins. With its unique set of genetic tools and a compact, well annotated genome, Drosophila is poised to remain a model system of choice for rapid progress in understanding principles of genome organization and to serve as a proving ground for development of 3D genome-engineering techniques.
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37
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Affiliation(s)
- Shalaka Chitale
- Laboratory of Molecular Epigenetics, Institute of Molecular Biology, Ackermannweg, Mainz, Germany
| | - Holger Richly
- Laboratory of Molecular Epigenetics, Institute of Molecular Biology, Ackermannweg, Mainz, Germany
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38
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Grob S, Grossniklaus U. Chromosome conformation capture-based studies reveal novel features of plant nuclear architecture. CURRENT OPINION IN PLANT BIOLOGY 2017; 36:149-157. [PMID: 28411415 DOI: 10.1016/j.pbi.2017.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 06/07/2023]
Abstract
Nuclear genome organization has recently received increasing attention due to its manifold functions in basic nuclear processes, such as replication, transcription, and the maintenance of genome integrity. Using technologies based on chromosome conformation capture, such as Hi-C, we now have the possibility to study the three-dimensional organization of the genome at unprecedented resolution, shedding light onto a previously unexplored level of nuclear architecture. In plants, research in this field is still in its infancy but a number of publications provided first insights into basic principles of nuclear genome organization and the factors that influence it. Apart from general aspects, newly discovered three-dimensional conformations, such as the KNOT, raise special interest on how nuclear organization may influence the function of the genome in previously unexpected ways.
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Affiliation(s)
- Stefan Grob
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland.
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
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39
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Connelly KE, Dykhuizen EC. Compositional and functional diversity of canonical PRC1 complexes in mammals. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:233-245. [PMID: 28007606 DOI: 10.1016/j.bbagrm.2016.12.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 12/17/2022]
Abstract
The compositional complexity of Polycomb Repressive Complex 1 (PRC1) increased dramatically during vertebrate evolution. What is considered the "canonical" PRC1 complex consists of four subunits originally identified as regulators of body segmentation in Drosophila. In mammals, each of these four canonical subunits consists of two to six paralogs that associate in a combinatorial manner to produce over a hundred possible distinct PRC1 complexes with unknown function. Genetic studies have begun to define the phenotypic roles for different PRC1 paralogs; however, relating these phenotypes to unique biochemical and transcriptional function for the different paralogs has been challenging. In this review, we attempt to address how the compositional diversity of canonical PRC1 complexes relates to unique roles for individual PRC1 paralogs in transcriptional regulation. This review focuses primarily on PRC1 complex composition, genome targeting, and biochemical function.
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Affiliation(s)
- Katelyn E Connelly
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA
| | - Emily C Dykhuizen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 201 S. University St., West Lafayette, IN 47907, USA; Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907, USA.
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40
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H3K27 methylation: a promiscuous repressive chromatin mark. Curr Opin Genet Dev 2016; 43:31-37. [PMID: 27940208 DOI: 10.1016/j.gde.2016.11.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022]
Abstract
Polycomb Repressive Complex 2 (PRC2) is a multiprotein complex that catalyzes the methylation of lysine 27 on histone H3 (H3K27me). This histone modification is a feature of facultative heterochromatin in many eukaryotes and maintains transcriptional repression established during early development. Understanding how PRC2 targets regions of the genome to be methylated remains poorly understood. Different cell types can show disparate patterns of H3K27me, and chromatin perturbations, such as loss of marks of constitutive heterochromatin, can cause redistribution of H3K27me, implying that DNA sequence, per se, is not sufficient to define the distribution of this mark. Emerging information supports the idea that the chromatin context-including histone modifications, DNA methylation, transcription, chromatin structure and organization within the nucleus-informs PRC2 target selection.
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41
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Han Y, He X. Integrating Epigenomics into the Understanding of Biomedical Insight. Bioinform Biol Insights 2016; 10:267-289. [PMID: 27980397 PMCID: PMC5138066 DOI: 10.4137/bbi.s38427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/01/2016] [Accepted: 11/06/2016] [Indexed: 12/13/2022] Open
Abstract
Epigenetics is one of the most rapidly expanding fields in biomedical research, and the popularity of the high-throughput next-generation sequencing (NGS) highlights the accelerating speed of epigenomics discovery over the past decade. Epigenetics studies the heritable phenotypes resulting from chromatin changes but without alteration on DNA sequence. Epigenetic factors and their interactive network regulate almost all of the fundamental biological procedures, and incorrect epigenetic information may lead to complex diseases. A comprehensive understanding of epigenetic mechanisms, their interactions, and alterations in health and diseases genome widely has become a priority in biological research. Bioinformatics is expected to make a remarkable contribution for this purpose, especially in processing and interpreting the large-scale NGS datasets. In this review, we introduce the epigenetics pioneering achievements in health status and complex diseases; next, we give a systematic review of the epigenomics data generation, summarize public resources and integrative analysis approaches, and finally outline the challenges and future directions in computational epigenomics.
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Affiliation(s)
- Yixing Han
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, USA.; Present address: Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ximiao He
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.; Present address: Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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42
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Olivares-Chauvet P, Mukamel Z, Lifshitz A, Schwartzman O, Elkayam NO, Lubling Y, Deikus G, Sebra RP, Tanay A. Capturing pairwise and multi-way chromosomal conformations using chromosomal walks. Nature 2016; 540:296-300. [DOI: 10.1038/nature20158] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 10/13/2016] [Indexed: 12/12/2022]
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43
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Long non-coding RNAs: spatial amplifiers that control nuclear structure and gene expression. Nat Rev Mol Cell Biol 2016; 17:756-770. [DOI: 10.1038/nrm.2016.126] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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44
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Mas G, Di Croce L. The role of Polycomb in stem cell genome architecture. Curr Opin Cell Biol 2016; 43:87-95. [PMID: 27690123 DOI: 10.1016/j.ceb.2016.09.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/02/2016] [Accepted: 09/12/2016] [Indexed: 02/06/2023]
Abstract
Polycomb-group proteins maintain embryonic stem cell identity by repressing genes that encode for developmental regulatory factors. Failure to properly control developmental transcription programs by Polycomb proteins is linked to disease and embryonic lethality. Recent technological advances have revealed that developmentally repressed genes tend to cluster in the three-dimensional space of the nucleus. Importantly, spatial clustering of developmental genes is fundamental for the correct regulation of gene expression during early development. Here, we outline novel insights and perspectives regarding the function of Polycomb complexes in shaping the stem cell genome architecture, and discuss how this function might be required to properly orchestrate transcriptional programs during differentiation.
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Affiliation(s)
- Gloria Mas
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
| | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; ICREA, Pg. Lluis Companys 23, 08010 Barcelona, Spain.
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45
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Buxa MK, Slotman JA, van Royen ME, Paul MW, Houtsmuller AB, Renkawitz R. Insulator speckles associated with long-distance chromatin contacts. Biol Open 2016; 5:1266-74. [PMID: 27464669 PMCID: PMC5051650 DOI: 10.1242/bio.019455] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nuclear foci of chromatin binding factors are, in many cases, discussed as sites of long-range chromatin interaction in the three-dimensional nuclear space. Insulator binding proteins have been shown to aggregate into insulator bodies, which are large structures not involved in insulation; however, the more diffusely distributed insulator speckles have not been analysed in this respect. Furthermore, insulator binding proteins have been shown to drive binding sites for Polycomb group proteins into Polycomb bodies. Here we find that insulator speckles, marked by the insulator binding protein dCTCF, and Polycomb bodies show differential association with the insulator protein CP190. They differ in number and three-dimensional location with only 26% of the Polycomb bodies overlapping with CP190. By using fluorescence in situ hybridization (FISH) probes to identify long-range interaction (kissing) of the Hox gene clusters Antennapedia complex (ANT-C) and Bithorax complex (BX-C), we found the frequency of interaction to be very low. However, these rare kissing events were associated with insulator speckles at a significantly shorter distance and an increased speckle number. This suggests that insulator speckles are associated with long-distance interaction.
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Affiliation(s)
- Melanie K Buxa
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58, Giessen D35392, Germany
| | - Johan A Slotman
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Postbus 2040, Rotterdam 3000 CA, The Netherlands
| | - Martin E van Royen
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Postbus 2040, Rotterdam 3000 CA, The Netherlands
| | - Maarten W Paul
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Postbus 2040, Rotterdam 3000 CA, The Netherlands
| | - Adriaan B Houtsmuller
- Department of Pathology, Josephine Nefkens Institute, Erasmus Optical Imaging Centre, Erasmus MC, Postbus 2040, Rotterdam 3000 CA, The Netherlands
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58, Giessen D35392, Germany
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46
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Entrevan M, Schuettengruber B, Cavalli G. Regulation of Genome Architecture and Function by Polycomb Proteins. Trends Cell Biol 2016; 26:511-525. [PMID: 27198635 DOI: 10.1016/j.tcb.2016.04.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 12/13/2022]
Abstract
Polycomb group (PcG) proteins dynamically define cellular identities through the epigenetic repression of key developmental regulatory genes. PcG proteins are recruited to specific regulatory elements to modify the chromatin surrounding them. In addition, they regulate the organization of their target genes in the 3D space of the nucleus, and this regulatory function of the 3D genome architecture is involved in cell differentiation and the maintenance of cellular memory. In this review we discuss recent advances in our understanding of how PcG proteins are recruited to chromatin to induce local and global changes in chromosome conformation and regulate their target genes.
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Affiliation(s)
- Marianne Entrevan
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Bernd Schuettengruber
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France.
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France.
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47
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Salminen A, Kaarniranta K, Kauppinen A. Hypoxia-Inducible Histone Lysine Demethylases: Impact on the Aging Process and Age-Related Diseases. Aging Dis 2016; 7:180-200. [PMID: 27114850 PMCID: PMC4809609 DOI: 10.14336/ad.2015.0929] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/29/2015] [Indexed: 12/18/2022] Open
Abstract
Hypoxia is an environmental stress at high altitude and underground conditions but it is also present in many chronic age-related diseases, where blood flow into tissues is impaired. The oxygen-sensing system stimulates gene expression protecting tissues against hypoxic insults. Hypoxia stabilizes the expression of hypoxia-inducible transcription factor-1α (HIF-1α), which controls the expression of hundreds of survival genes related to e.g. enhanced energy metabolism and autophagy. Moreover, many stress-related signaling mechanisms, such as oxidative stress and energy metabolic disturbances, as well as the signaling cascades via ceramide, mTOR, NF-κB, and TGF-β pathways, can also induce the expression of HIF-1α protein to facilitate cell survival in normoxia. Hypoxia is linked to prominent epigenetic changes in chromatin landscape. Screening studies have indicated that the stabilization of HIF-1α increases the expression of distinct histone lysine demethylases (KDM). HIF-1α stimulates the expression of KDM3A, KDM4B, KDM4C, and KDM6B, which enhance gene transcription by demethylating H3K9 and H3K27 sites (repressive epigenetic marks). In addition, HIF-1α induces the expression of KDM2B and KDM5B, which repress transcription by demethylating H3K4me2,3 sites (activating marks). Hypoxia-inducible KDMs support locally the gene transcription induced by HIF-1α, although they can also control genome-wide chromatin landscape, especially KDMs which demethylate H3K9 and H3K27 sites. These epigenetic marks have important role in the control of heterochromatin segments and 3D folding of chromosomes, as well as the genetic loci regulating cell type commitment, proliferation, and cellular senescence, e.g. the INK4 box. A chronic stimulation of HIF-1α can provoke tissue fibrosis and cellular senescence, which both are increasingly present with aging and age-related diseases. We will review the regulation of HIF-1α-dependent induction of KDMs and clarify their role in pathological processes emphasizing that long-term stress-related insults can impair the maintenance of chromatin landscape and provoke cellular senescence and tissue fibrosis associated with aging and age-related diseases.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Kuopio University Hospital, Finland; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
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48
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Solovei I, Thanisch K, Feodorova Y. How to rule the nucleus: divide et impera. Curr Opin Cell Biol 2016; 40:47-59. [PMID: 26938331 DOI: 10.1016/j.ceb.2016.02.014] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/04/2016] [Accepted: 02/14/2016] [Indexed: 01/14/2023]
Abstract
Genome-wide molecular studies have provided new insights into the organization of nuclear chromatin by revealing the presence of chromatin domains of differing transcriptional activity, frequency of cis-interactions, proximity to scaffolding structures and replication timing. These studies have not only brought our understanding of genome function to a new level, but also offered functional insight for many phenomena observed in microscopic studies. In this review, we discuss the major principles of nuclear organization based on the spatial segregation of euchromatin and heterochromatin, as well as the dynamic genome rearrangements occurring during cell differentiation and development. We hope to unite the existing molecular and microscopic data on genome organization to get a holistic view of the nucleus, and propose a model, in which repeat repertoire together with scaffolding structures blueprint the functional nuclear architecture.
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Affiliation(s)
- Irina Solovei
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany.
| | - Katharina Thanisch
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany
| | - Yana Feodorova
- Department of Biology II, Ludwig Maximilians University Munich, Grosshadernerstrasse 2, Planegg-Martinsried 82152, Germany; Department of Medical Biology, Medical University-Plovdiv, Boulevard Vasil Aprilov 15A, Plovdiv 4000, Bulgaria
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49
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Marullo F, Cesarini E, Antonelli L, Gregoretti F, Oliva G, Lanzuolo C. Nucleoplasmic Lamin A/C and Polycomb group of proteins: An evolutionarily conserved interplay. Nucleus 2016; 7:103-11. [PMID: 26930442 PMCID: PMC4916880 DOI: 10.1080/19491034.2016.1157675] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nuclear lamins are the main components of the nuclear lamina at the nuclear periphery, providing mechanical support to the nucleus. However, recent findings suggest that lamins also reside in the nuclear interior, as a distinct and dynamic pool with critical roles in transcriptional regulation. In our work we found a functional and evolutionary conserved crosstalk between Lamin A/C and the Polycomb group (PcG) of proteins, this being required for the maintenance of the PcG repressive functions. Indeed, Lamin A/C knock-down causes PcG foci dispersion and defects in PcG-mediated higher order structures, thereby leading to impaired PcG mediated transcriptional repression. By using ad-hoc algorithms for image analysis and PLA approaches we hereby show that PcG proteins are preferentially located in the nuclear interior where they interact with nucleoplasmic Lamin A/C. Taken together, our findings suggest that nuclear components, such as Lamin A/C, functionally interact with epigenetic factors to ensure the correct transcriptional program maintenance.
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Affiliation(s)
- F Marullo
- a CNR Institute of Cell Biology and Neurobiology, IRCCS Santa Lucia Foundation , Rome , Italy
| | - E Cesarini
- a CNR Institute of Cell Biology and Neurobiology, IRCCS Santa Lucia Foundation , Rome , Italy
| | - L Antonelli
- b CNR Institute for High Performance Computing and Networking (ICAR) , Naples, Italy
| | - F Gregoretti
- b CNR Institute for High Performance Computing and Networking (ICAR) , Naples, Italy
| | - G Oliva
- b CNR Institute for High Performance Computing and Networking (ICAR) , Naples, Italy
| | - C Lanzuolo
- a CNR Institute of Cell Biology and Neurobiology, IRCCS Santa Lucia Foundation , Rome , Italy.,c Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
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50
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Wijchers PJ, Krijger PHL, Geeven G, Zhu Y, Denker A, Verstegen MJAM, Valdes-Quezada C, Vermeulen C, Janssen M, Teunissen H, Anink-Groenen LCM, Verschure PJ, de Laat W. Cause and Consequence of Tethering a SubTAD to Different Nuclear Compartments. Mol Cell 2016; 61:461-473. [PMID: 26833089 PMCID: PMC4747903 DOI: 10.1016/j.molcel.2016.01.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/30/2015] [Accepted: 12/22/2015] [Indexed: 12/11/2022]
Abstract
Detailed genomic contact maps have revealed that chromosomes are structurally organized in megabase-sized topologically associated domains (TADs) that encompass smaller subTADs. These domains segregate in the nuclear space to form active and inactive nuclear compartments, but cause and consequence of compartmentalization are largely unknown. Here, we combined lacO/lacR binding platforms with allele-specific 4C technologies to track their precise position in the three-dimensional genome upon recruitment of NANOG, SUV39H1, or EZH2. We observed locked genomic loci resistant to spatial repositioning and unlocked loci that could be repositioned to different nuclear subcompartments with distinct chromatin signatures. Focal protein recruitment caused the entire subTAD, but not surrounding regions, to engage in new genomic contacts. Compartment switching was found uncoupled from transcription changes, and the enzymatic modification of histones per se was insufficient for repositioning. Collectively, this suggests that trans-associated factors influence three-dimensional compartmentalization independent of their cis effect on local chromatin composition and activity.
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Affiliation(s)
- Patrick J Wijchers
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Peter H L Krijger
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Geert Geeven
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Yun Zhu
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Annette Denker
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Marjon J A M Verstegen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Christian Valdes-Quezada
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Carlo Vermeulen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Mark Janssen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Hans Teunissen
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands
| | - Lisette C M Anink-Groenen
- Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Pernette J Verschure
- Synthetic Systems Biology and Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Wouter de Laat
- Hubrecht Institute-KNAW & University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
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