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:S1097-2765(24)00628-2. [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] [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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Briffa A, Menon G, Movilla Miangolarra A, Howard M. Dissecting Mechanisms of Epigenetic Memory Through Computational Modeling. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:265-290. [PMID: 38424070 DOI: 10.1146/annurev-arplant-070523-041445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Understanding the mechanistic basis of epigenetic memory has proven to be a difficult task due to the underlying complexity of the systems involved in its establishment and maintenance. Here, we review the role of computational modeling in helping to unlock this complexity, allowing the dissection of intricate feedback dynamics. We focus on three forms of epigenetic memory encoded in gene regulatory networks, DNA methylation, and histone modifications and discuss the important advantages offered by plant systems in their dissection. We summarize the main modeling approaches involved and highlight the principal conceptual advances that the modeling has enabled through iterative cycles of predictive modeling and experiments. Lastly, we discuss remaining gaps in our understanding and how intertwined theory and experimental approaches might help in their resolution.
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Affiliation(s)
- Amy Briffa
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
- Epigenetics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Govind Menon
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
| | - Ander Movilla Miangolarra
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom;
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3
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Menon G, Mateo-Bonmati E, Reeck S, Maple R, Wu Z, Ietswaart R, Dean C, Howard M. Proximal termination generates a transcriptional state that determines the rate of establishment of Polycomb silencing. Mol Cell 2024; 84:2255-2271.e9. [PMID: 38851186 DOI: 10.1016/j.molcel.2024.05.014] [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: 07/10/2023] [Revised: 02/28/2024] [Accepted: 05/14/2024] [Indexed: 06/10/2024]
Abstract
The mechanisms and timescales controlling de novo establishment of chromatin-mediated transcriptional silencing by Polycomb repressive complex 2 (PRC2) are unclear. Here, we investigate PRC2 silencing at Arabidopsis FLOWERING LOCUS C (FLC), known to involve co-transcriptional RNA processing, histone demethylation activity, and PRC2 function, but so far not mechanistically connected. We develop and test a computational model describing proximal polyadenylation/termination mediated by the RNA-binding protein FCA that induces H3K4me1 removal by the histone demethylase FLD. H3K4me1 removal feeds back to reduce RNA polymerase II (RNA Pol II) processivity and thus enhance early termination, thereby repressing productive transcription. The model predicts that this transcription-coupled repression controls the level of transcriptional antagonism to PRC2 action. Thus, the effectiveness of this repression dictates the timescale for establishment of PRC2/H3K27me3 silencing. We experimentally validate these mechanistic model predictions, revealing that co-transcriptional processing sets the level of productive transcription at the locus, which then determines the rate of the ON-to-OFF switch to PRC2 silencing.
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Affiliation(s)
- Govind Menon
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Eduardo Mateo-Bonmati
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Svenja Reeck
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Robert Maple
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Zhe Wu
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Robert Ietswaart
- Harvard Medical School, Department of Genetics, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Caroline Dean
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
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4
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Glancy E, Choy N, Eckersley-Maslin MA. Bivalent chromatin: a developmental balancing act tipped in cancer. Biochem Soc Trans 2024; 52:217-229. [PMID: 38385532 PMCID: PMC10903468 DOI: 10.1042/bst20230426] [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: 11/21/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 02/23/2024]
Abstract
Bivalent chromatin is defined by the co-occurrence of otherwise opposing H3K4me3 and H3K27me3 modifications and is typically located at unmethylated promoters of lowly transcribed genes. In embryonic stem cells, bivalent chromatin has been proposed to poise developmental genes for future activation, silencing or stable repression upon lineage commitment. Normally, bivalent chromatin is kept in tight balance in cells, in part through the activity of the MLL/COMPASS-like and Polycomb repressive complexes that deposit the H3K4me3 and H3K27me3 modifications, respectively, but also emerging novel regulators including DPPA2/4, QSER1, BEND3, TET1 and METTL14. In cancers, both the deregulation of existing domains and the creation of de novo bivalent states is associated with either the activation or silencing of transcriptional programmes. This may facilitate diverse aspects of cancer pathology including epithelial-to-mesenchymal plasticity, chemoresistance and immune evasion. Here, we review current methods for detecting bivalent chromatin and discuss the factors involved in the formation and fine-tuning of bivalent domains. Finally, we examine how the deregulation of chromatin bivalency in the context of cancer could facilitate and/or reflect cancer cell adaptation. We propose a model in which bivalent chromatin represents a dynamic balance between otherwise opposing states, where the underlying DNA sequence is primed for the future activation or repression. Shifting this balance in any direction disrupts the tight equilibrium and tips cells into an altered epigenetic and phenotypic space, facilitating both developmental and cancer processes.
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Affiliation(s)
- Eleanor Glancy
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Natalie Choy
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Melanie A. Eckersley-Maslin
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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5
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Li R, Huang D, Zhao Y, Yuan Y, Sun X, Dai Z, Huo D, Liu X, Helin K, Li MJ, Wu X. PR-DUB safeguards Polycomb repression through H2AK119ub1 restriction. Cell Prolif 2023; 56:e13457. [PMID: 36959757 PMCID: PMC10542648 DOI: 10.1111/cpr.13457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/01/2023] [Accepted: 03/11/2023] [Indexed: 03/25/2023] Open
Abstract
Polycomb group (PcG) proteins are critical chromatin regulators for cell fate control. The mono-ubiquitylation on histone H2AK119 (H2AK119ub1) is one of the well-recognized mechanisms for Polycomb repressive complex 1 (PRC1)-mediated transcription repression. Unexpectedly, the specific H2AK119 deubiquitylation complex composed by additional sex comb-like proteins and BAP1 has also been genetically characterized as Polycomb repressive deubiquitnase (PR-DUB) for unclear reasons. However, it remains a mystery whether and how PR-DUB deficiency affects chromatin states and cell fates through impaired PcG silencing. Here through a careful epigenomic analysis, we demonstrate that a bulk of H2AK119ub1 is diffusely distributed away from promoter regions and their enrichment is positively correlated with PRC1 occupancy. Upon deletion of Asxl2 in mouse embryonic stem cells (ESCs), a pervasive gain of H2AK119ub1 is coincident with increased PRC1 sampling at chromatin. Accordingly, PRC1 is significantly lost from a subset of highly occupied promoters, leading to impaired silencing of associated genes before and after lineage differentiation of Asxl2-null ESCs. Therefore, our study highlights the importance of genome-wide H2AK119ub1 restriction by PR-DUB in safeguarding robust PRC1 deposition and its roles in developmental regulation.
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Affiliation(s)
- Rui Li
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Dandan Huang
- Wuxi School of MedicineJiangnan UniversityWuxi214000China
| | - Yingying Zhao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Ye Yuan
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Xiaoyu Sun
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Zhongye Dai
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Dawei Huo
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
| | - Xiaozhi Liu
- Pediatric Center, Tianjin Key Laboratory of Epigenetics for Organ Development of Premature InfantsThe Fifth Central Hospital of TianjinTianjin300450China
| | - Kristian Helin
- Biotech Research and Innovation CentreUniversity of CopenhagenCopenhagenDenmark
- The Institute of Cancer Research (ICR)LondonUK
| | - Mulin Jun Li
- Department of Bioinformatics, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
- Department of Epidemiology and Biostatistics, National Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and HospitalTianjin Medical UniversityTianjin300070China
| | - Xudong Wu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co‐sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Cell Biology, School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China
- Department of OrthopedicsTianjin Medical University General HospitalTianjin300052China
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6
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Wu Q, Wu J, Karim K, Chen X, Wang T, Iwama S, Carobbio S, Keen P, Vidal-Puig A, Kotter MR, Bassett A. Massively parallel characterization of CRISPR activator efficacy in human induced pluripotent stem cells and neurons. Mol Cell 2023; 83:1125-1139.e8. [PMID: 36917981 PMCID: PMC10114495 DOI: 10.1016/j.molcel.2023.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 12/21/2022] [Accepted: 02/10/2023] [Indexed: 03/14/2023]
Abstract
CRISPR activation (CRISPRa) is an important tool to perturb transcription, but its effectiveness varies between target genes. We employ human pluripotent stem cells with thousands of randomly integrated barcoded reporters to assess epigenetic features that influence CRISPRa efficacy. Basal expression levels are influenced by genomic context and dramatically change during differentiation to neurons. Gene activation by dCas9-VPR is successful in most genomic contexts, including developmentally repressed regions, and activation level is anti-correlated with basal gene expression, whereas dCas9-p300 is ineffective in stem cells. Certain chromatin states, such as bivalent chromatin, are particularly sensitive to dCas9-VPR, whereas constitutive heterochromatin is less responsive. We validate these rules at endogenous genes and show that activation of certain genes elicits a change in the stem cell transcriptome, sometimes showing features of differentiated cells. Our data provide rules to predict CRISPRa outcome and highlight its utility to screen for factors driving stem cell differentiation.
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Affiliation(s)
- Qianxin Wu
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.
| | - Junjing Wu
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Kaiser Karim
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Xi Chen
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Southern University of Science and Technology, 1088 Xueyuan Ave, Nanshan, Shenzhen, Guangdong 518055, China
| | - Tengyao Wang
- Department of Statistics, London School of Economics and Political Science, London WC2B 4RR, UK
| | - Sho Iwama
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Stefania Carobbio
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Metabolic Research Laboratories, Addenbrooke's Treatment Center, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK; Centro de Investigacion Principe Felipe, 46012 Valencia, Spain
| | - Peter Keen
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Antonio Vidal-Puig
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Metabolic Research Laboratories, Addenbrooke's Treatment Center, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK; Centro de Investigacion Principe Felipe, 46012 Valencia, Spain
| | - Mark R Kotter
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Andrew Bassett
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.
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7
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Scholl A, De S. Epigenetic Regulation by Polycomb Complexes from Drosophila to Human and Its Relation to Communicable Disease Pathogenesis. Int J Mol Sci 2022; 23:ijms232012285. [PMID: 36293135 PMCID: PMC9603650 DOI: 10.3390/ijms232012285] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/04/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Although all cells in the human body are made of the same DNA, these cells undergo differentiation and behave differently during development, through integration of external and internal stimuli via 'specific mechanisms.' Epigenetics is one such mechanism that comprises DNA/RNA, histone modifications, and non-coding RNAs that regulate transcription without changing the genetic code. The discovery of the first Polycomb mutant phenotype in Drosophila started the study of epigenetics more than 80 years ago. Since then, a considerable number of Polycomb Group (PcG) genes in Drosophila have been discovered to be preserved in mammals, including humans. PcG proteins exert their influence through gene repression by acting in complexes, modifying histones, and compacting the chromatin within the nucleus. In this article, we discuss how our knowledge of the PcG repression mechanism in Drosophila translates to human communicable disease research.
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8
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Mikulski P, Wolff P, Lu T, Nielsen M, Echevarria EF, Zhu D, Questa JI, Saalbach G, Martins C, Dean C. VAL1 acts as an assembly platform co-ordinating co-transcriptional repression and chromatin regulation at Arabidopsis FLC. Nat Commun 2022; 13:5542. [PMID: 36130923 PMCID: PMC9492735 DOI: 10.1038/s41467-022-32897-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/23/2022] [Indexed: 12/04/2022] Open
Abstract
Polycomb (PcG) silencing is crucial for development, but how targets are specified remains incompletely understood. The cold-induced Polycomb Repressive Complex 2 (PRC2) silencing of Arabidopsis thaliana FLOWERING LOCUS C (FLC) provides an excellent system to elucidate PcG regulation. Association of the DNA binding protein VAL1 to FLC PcG nucleation regionis an important step. VAL1 co-immunoprecipitates APOPTOSIS AND SPLICING ASSOCIATED PROTEIN (ASAP) complex and PRC1. Here, we show that ASAP and PRC1 are necessary for co-transcriptional repression and chromatin regulation at FLC. ASAP mutants affect FLC transcription in warm conditions, but the rate of FLC silencing in the cold is unaffected. PRC1-mediated H2Aub accumulation increases at the FLC nucleation region during cold, but unlike the PRC2-delivered H3K27me3, does not spread across the locus. H2Aub thus involved in the transition to epigenetic silencing at FLC, facilitating H3K27me3 accumulation and long-term epigenetic memory. Overall, our work highlights the importance of VAL1 as an assembly platform co-ordinating activities necessary for epigenetic silencing at FLC.
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Affiliation(s)
- Pawel Mikulski
- Cell and Developmental Biology, John Innes Centre, Norwich, UK. .,Department of Biochemistry, University of Oxford, Oxford, UK.
| | - Philip Wolff
- Cell and Developmental Biology, John Innes Centre, Norwich, UK
| | - Tiancong Lu
- Cell and Developmental Biology, John Innes Centre, Norwich, UK.,State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Mathias Nielsen
- Cell and Developmental Biology, John Innes Centre, Norwich, UK
| | | | - Danling Zhu
- Cell and Developmental Biology, John Innes Centre, Norwich, UK.,SUSTech-PKU Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Julia I Questa
- Cell and Developmental Biology, John Innes Centre, Norwich, UK.,Centre for Research in Agricultural Genomics, Barcelona, Spain
| | | | - Carlo Martins
- Biological Chemistry, John Innes Centre, Norwich, UK
| | - Caroline Dean
- Cell and Developmental Biology, John Innes Centre, Norwich, UK. .,MRC Laboratory of Molecular Biology, Cambridge, UK.
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9
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De Novo Polycomb Recruitment and Repressive Domain Formation. EPIGENOMES 2022; 6:epigenomes6030025. [PMID: 35997371 PMCID: PMC9397058 DOI: 10.3390/epigenomes6030025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Every cell of an organism shares the same genome; even so, each cellular lineage owns a different transcriptome and proteome. The Polycomb group proteins (PcG) are essential regulators of gene repression patterning during development and homeostasis. However, it is unknown how the repressive complexes, PRC1 and PRC2, identify their targets and elicit new Polycomb domains during cell differentiation. Classical recruitment models consider the pre-existence of repressive histone marks; still, de novo target binding overcomes the absence of both H3K27me3 and H2AK119ub. The CpG islands (CGIs), non-core proteins, and RNA molecules are involved in Polycomb recruitment. Nonetheless, it is unclear how de novo targets are identified depending on the physiological context and developmental stage and which are the leading players stabilizing Polycomb complexes at domain nucleation sites. Here, we examine the features of de novo sites and the accessory elements bridging its recruitment and discuss the first steps of Polycomb domain formation and transcriptional regulation, comprehended by the experimental reconstruction of the repressive domains through time-resolved genomic analyses in mammals.
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10
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Karn V, Sandhya S, Hsu W, Parashar D, Singh HN, Jha NK, Gupta S, Dubey NK, Kumar S. CRISPR/Cas9 system in breast cancer therapy: advancement, limitations and future scope. Cancer Cell Int 2022; 22:234. [PMID: 35879772 PMCID: PMC9316746 DOI: 10.1186/s12935-022-02654-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/12/2022] [Indexed: 12/13/2022] Open
Abstract
Cancer is one of the major causes of mortality worldwide, therefore it is considered a major health concern. Breast cancer is the most frequent type of cancer which affects women on a global scale. Various current treatment strategies have been implicated for breast cancer therapy that includes surgical removal, radiation therapy, hormonal therapy, chemotherapy, and targeted biological therapy. However, constant effort is being made to introduce novel therapies with minimal toxicity. Gene therapy is one of the promising tools, to rectify defective genes and cure various cancers. In recent years, a novel genome engineering technology, namely the clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein-9 (Cas9) has emerged as a gene-editing tool and transformed genome-editing techniques in a wide range of biological domains including human cancer research and gene therapy. This could be attributed to its versatile characteristics such as high specificity, precision, time-saving and cost-effective methodologies with minimal risk. In the present review, we highlight the role of CRISPR/Cas9 as a targeted therapy to tackle drug resistance, improve immunotherapy for breast cancer.
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Affiliation(s)
- Vamika Karn
- Department of Biotechnology, Amity University, Mumbai, 410221, India
| | - Sandhya Sandhya
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Wayne Hsu
- Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei, 110, Taiwan
| | - Deepak Parashar
- Department of Obstetrics and Gynaecology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Himanshu Narayan Singh
- Department of System Biology, Columbia University Irving Medical Centre, New York, NY, 10032, USA
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida, 201310, India.,Department of Biotechnology, School of Applied & Life Sciences (SALS), Uttaranchal University, Dehradun, 248007, India.,Department of Biotechnology Engineering and Food Technology, Chandigarh University, Mohali, 140413, India
| | - Saurabh Gupta
- Department of Biotechnology, GLA University, Mathura, Uttar Pradesh, India
| | - Navneet Kumar Dubey
- Victory Biotechnology Co., Ltd., Taipei, 114757, Taiwan. .,ShiNeo Technology Co., Ltd., New Taipei City, 24262, Taiwan.
| | - Sanjay Kumar
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida, 201310, India.
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11
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CpG island reconfiguration for the establishment and synchronization of polycomb functions upon exit from naive pluripotency. Mol Cell 2022; 82:1169-1185.e7. [PMID: 35202573 DOI: 10.1016/j.molcel.2022.01.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/03/2021] [Accepted: 01/27/2022] [Indexed: 12/12/2022]
Abstract
Polycomb group (PcG) proteins are essential for post-implantation development by depositing repressive histone modifications at promoters, mainly CpG islands (CGIs), of developmental regulator genes. However, promoter PcG marks are erased after fertilization and de novo established in peri-implantation embryos, coinciding with the transition from naive to primed pluripotency. Nevertheless, the molecular basis for this establishment remains unknown. In this study, we show that the expression of the long KDM2B isoform (KDM2BLF), which contains the demethylase domain, is specifically induced at peri-implantation and that its H3K36me2 demethylase activity is required for PcG enrichment at CGIs. Moreover, KDM2BLF interacts with BRG1/BRM-associated factor (BAF) and stabilizes BAF occupancy at CGIs for subsequent gain of accessibility, which precedes PcG enrichment. Consistently, KDM2BLF inactivation results in significantly delayed post-implantation development. In summary, our data unveil dynamic chromatin configuration of CGIs during exit from naive pluripotency and provide a conceptual framework for the spatiotemporal establishment of PcG functions.
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12
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Meanor JN, Keung AJ, Rao BM. Modified Histone Peptides Linked to Magnetic Beads Reduce Binding Specificity. Int J Mol Sci 2022; 23:ijms23031691. [PMID: 35163614 PMCID: PMC8836101 DOI: 10.3390/ijms23031691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/20/2022] [Accepted: 01/29/2022] [Indexed: 12/03/2022] Open
Abstract
Histone post-translational modifications are small chemical changes to the histone protein structure that have cascading effects on diverse cellular functions. Detecting histone modifications and characterizing their binding partners are critical steps in understanding chromatin biochemistry and have been accessed using common reagents such as antibodies, recombinant assays, and FRET-based systems. High-throughput platforms could accelerate work in this field, and also could be used to engineer de novo histone affinity reagents; yet, published studies on their use with histones have been noticeably sparse. Here, we describe specific experimental conditions that affect binding specificities of post-translationally modified histones in classic protein engineering platforms and likely explain the relative difficulty with histone targets in these platforms. We also show that manipulating avidity of binding interactions may improve specificity of binding.
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Affiliation(s)
- Jenna N. Meanor
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Campus Box 7905, Raleigh, NC 27606, USA;
| | - Albert J. Keung
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Campus Box 7905, Raleigh, NC 27606, USA;
- Correspondence: (A.J.K.); (B.M.R.)
| | - Balaji M. Rao
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Campus Box 7905, Raleigh, NC 27606, USA;
- Golden LEAF Biomanufacturing Training and Education Center (BTEC), North Carolina State University, Raleigh, NC 27695, USA
- Correspondence: (A.J.K.); (B.M.R.)
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13
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Blackledge NP, Klose RJ. The molecular principles of gene regulation by Polycomb repressive complexes. Nat Rev Mol Cell Biol 2021; 22:815-833. [PMID: 34400841 PMCID: PMC7612013 DOI: 10.1038/s41580-021-00398-y] [Citation(s) in RCA: 178] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2021] [Indexed: 12/12/2022]
Abstract
Precise control of gene expression is fundamental to cell function and development. Although ultimately gene expression relies on DNA-binding transcription factors to guide the activity of the transcription machinery to genes, it has also become clear that chromatin and histone post-translational modification have fundamental roles in gene regulation. Polycomb repressive complexes represent a paradigm of chromatin-based gene regulation in animals. The Polycomb repressive system comprises two central protein complexes, Polycomb repressive complex 1 (PRC1) and PRC2, which are essential for normal gene regulation and development. Our early understanding of Polycomb function relied on studies in simple model organisms, but more recently it has become apparent that this system has expanded and diverged in mammals. Detailed studies are now uncovering the molecular mechanisms that enable mammalian PRC1 and PRC2 to identify their target sites in the genome, communicate through feedback mechanisms to create Polycomb chromatin domains and control transcription to regulate gene expression. In this Review, we discuss and contextualize the emerging principles that define how this fascinating chromatin-based system regulates gene expression in mammals.
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Affiliation(s)
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, UK.
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14
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Dobrinić P, Szczurek AT, Klose RJ. PRC1 drives Polycomb-mediated gene repression by controlling transcription initiation and burst frequency. Nat Struct Mol Biol 2021; 28:811-824. [PMID: 34608337 PMCID: PMC7612713 DOI: 10.1038/s41594-021-00661-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 08/10/2021] [Indexed: 12/15/2022]
Abstract
The Polycomb repressive system plays a fundamental role in controlling gene expression during mammalian development. To achieve this, Polycomb repressive complexes 1 and 2 (PRC1 and PRC2) bind target genes and use histone modification-dependent feedback mechanisms to form Polycomb chromatin domains and repress transcription. The inter-relatedness of PRC1 and PRC2 activity at these sites has made it difficult to discover the specific components of Polycomb chromatin domains that drive gene repression and to understand mechanistically how this is achieved. Here, by exploiting rapid degron-based approaches and time-resolved genomics, we kinetically dissect Polycomb-mediated repression and discover that PRC1 functions independently of PRC2 to counteract RNA polymerase II binding and transcription initiation. Using single-cell gene expression analysis, we reveal that PRC1 acts uniformly within the cell population and that repression is achieved by controlling transcriptional burst frequency. These important new discoveries provide a mechanistic and conceptual framework for Polycomb-dependent transcriptional control.
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Affiliation(s)
- Paula Dobrinić
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, UK.
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15
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Keeping your options open: insights from Dppa2/4 into how epigenetic priming factors promote cell plasticity. Biochem Soc Trans 2021; 48:2891-2902. [PMID: 33336687 PMCID: PMC7752079 DOI: 10.1042/bst20200873] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
The concept of cellular plasticity is particularly apt in early embryonic development, where there is a tug-of-war between the stability and flexibility of cell identity. This balance is controlled in part through epigenetic mechanisms. Epigenetic plasticity dictates how malleable cells are to change by adjusting the potential to initiate new transcriptional programmes. The higher the plasticity of a cell, the more readily it can adapt and change its identity in response to external stimuli such as differentiation cues. Epigenetic plasticity is regulated in part through the action of epigenetic priming factors which establish this permissive epigenetic landscape at genomic regulatory elements to enable future transcriptional changes. Recent studies on the DNA binding proteins Developmental Pluripotency Associated 2 and 4 (Dppa2/4) support their roles as epigenetic priming factors in facilitating cell fate transitions. Here, using Dppa2/4 as a case study, the concept of epigenetic plasticity and molecular mechanism of epigenetic priming factors will be explored. Understanding how epigenetic priming factors function is key not only to improve our understanding of the tight control of development, but also to give insights into how this goes awry in diseases of cell identity, such as cancer.
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16
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Brown K, Andrianakos H, Ingersoll S, Ren X. Single-molecule imaging of epigenetic complexes in living cells: insights from studies on Polycomb group proteins. Nucleic Acids Res 2021; 49:6621-6637. [PMID: 34009336 PMCID: PMC8266577 DOI: 10.1093/nar/gkab304] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 04/09/2021] [Accepted: 04/13/2021] [Indexed: 12/30/2022] Open
Abstract
Chromatin-associated factors must locate, bind to, and assemble on specific chromatin regions to execute chromatin-templated functions. These dynamic processes are essential for understanding how chromatin achieves regulation, but direct quantification in living mammalian cells remains challenging. Over the last few years, live-cell single-molecule tracking (SMT) has emerged as a new way to observe trajectories of individual chromatin-associated factors in living mammalian cells, providing new perspectives on chromatin-templated activities. Here, we discuss the relative merits of live-cell SMT techniques currently in use. We provide new insights into how Polycomb group (PcG) proteins, master regulators of development and cell differentiation, decipher genetic and epigenetic information to achieve binding stability and highlight that Polycomb condensates facilitate target-search efficiency. We provide perspectives on liquid-liquid phase separation in organizing Polycomb targets. We suggest that epigenetic complexes integrate genetic and epigenetic information for target binding and localization and achieve target-search efficiency through nuclear organization.
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Affiliation(s)
- Kyle Brown
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
| | | | - Steven Ingersoll
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Xiaojun Ren
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
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17
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Ghotbi E, Ye P, Ervin T, Kum A, Benes J, Jones RS. Polycomb-group recruitment to a Drosophila target gene is the default state that is inhibited by a transcriptional activator. SCIENCE ADVANCES 2021; 7:7/29/eabg1556. [PMID: 34272248 PMCID: PMC8284896 DOI: 10.1126/sciadv.abg1556] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/25/2021] [Indexed: 06/13/2023]
Abstract
Polycomb-group (PcG) proteins are epigenetic regulators that maintain the transcriptional repression of target genes following their initial repression by transcription factors. PcG target genes are repressed in some cells, but active in others. Therefore, a mechanism must exist by which PcG proteins distinguish between the repressed and active states and only assemble repressive chromatin environments at target genes that are repressed. Here, we present experimental evidence that the repressed state of a Drosophila PcG target gene, giant (gt), is not identified by the presence of a repressor. Rather, de novo establishment of PcG-mediated silencing at gt is the default state that is prevented by the presence of an activator or coactivator, which may inhibit the catalytic activity of Polycomb-repressive complex 2 (PRC2).
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Affiliation(s)
- Elnaz Ghotbi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Piao Ye
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Taylor Ervin
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Anni Kum
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Judith Benes
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Richard S Jones
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA.
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18
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IMITATION SWITCH is required for normal chromatin structure and gene repression in PRC2 target domains. Proc Natl Acad Sci U S A 2021; 118:2010003118. [PMID: 33468665 DOI: 10.1073/pnas.2010003118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Polycomb Group (PcG) proteins are part of an epigenetic cell memory system that plays essential roles in multicellular development, stem cell biology, X chromosome inactivation, and cancer. In animals, plants, and many fungi, Polycomb Repressive Complex 2 (PRC2) catalyzes trimethylation of histone H3 lysine 27 (H3K27me3) to assemble transcriptionally repressed facultative heterochromatin. PRC2 is structurally and functionally conserved in the model fungus Neurospora crassa, and recent work in this organism has generated insights into PRC2 control and function. To identify components of the facultative heterochromatin pathway, we performed a targeted screen of Neurospora deletion strains lacking individual ATP-dependent chromatin remodeling enzymes. We found the Neurospora homolog of IMITATION SWITCH (ISW) is critical for normal transcriptional repression, nucleosome organization, and establishment of typical histone methylation patterns in facultative heterochromatin domains. We also found that stable interaction between PRC2 and chromatin depends on ISW. A functional ISW ATPase domain is required for gene repression and normal H3K27 methylation. ISW homologs interact with accessory proteins to form multiple complexes with distinct functions. Using proteomics and molecular approaches, we identified three distinct Neurospora ISW-containing complexes. A triple mutant lacking three ISW accessory factors and disrupting multiple ISW complexes led to widespread up-regulation of PRC2 target genes and altered H3K27 methylation patterns, similar to an ISW-deficient strain. Taken together, our data show that ISW is a key component of the facultative heterochromatin pathway in Neurospora, and that distinct ISW complexes perform an apparently overlapping role to regulate chromatin structure and gene repression at PRC2 target domains.
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19
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Fursova NA, Turberfield AH, Blackledge NP, Findlater EL, Lastuvkova A, Huseyin MK, Dobrinić P, Klose RJ. BAP1 constrains pervasive H2AK119ub1 to control the transcriptional potential of the genome. Genes Dev 2021; 35:749-770. [PMID: 33888563 PMCID: PMC8091973 DOI: 10.1101/gad.347005.120] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/02/2021] [Indexed: 12/21/2022]
Abstract
Histone-modifying systems play fundamental roles in gene regulation and the development of multicellular organisms. Histone modifications that are enriched at gene regulatory elements have been heavily studied, but the function of modifications found more broadly throughout the genome remains poorly understood. This is exemplified by histone H2A monoubiquitylation (H2AK119ub1), which is enriched at Polycomb-repressed gene promoters but also covers the genome at lower levels. Here, using inducible genetic perturbations and quantitative genomics, we found that the BAP1 deubiquitylase plays an essential role in constraining H2AK119ub1 throughout the genome. Removal of BAP1 leads to pervasive genome-wide accumulation of H2AK119ub1, which causes widespread reductions in gene expression. We show that elevated H2AK119ub1 preferentially counteracts Ser5 phosphorylation on the C-terminal domain of RNA polymerase II at gene regulatory elements and causes reductions in transcription and transcription-associated histone modifications. Furthermore, failure to constrain pervasive H2AK119ub1 compromises Polycomb complex occupancy at a subset of Polycomb target genes, which leads to their derepression, providing a potential molecular rationale for why the BAP1 ortholog in Drosophila has been characterized as a Polycomb group gene. Together, these observations reveal that the transcriptional potential of the genome can be modulated by regulating the levels of a pervasive histone modification.
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Affiliation(s)
- Nadezda A Fursova
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Anne H Turberfield
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Neil P Blackledge
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Emma L Findlater
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Anna Lastuvkova
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Miles K Huseyin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Paula Dobrinić
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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20
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Polycomb-group proteins in the initiation and progression of cancer. J Genet Genomics 2021; 48:433-443. [PMID: 34266781 DOI: 10.1016/j.jgg.2021.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/23/2021] [Accepted: 03/28/2021] [Indexed: 12/13/2022]
Abstract
The Polycomb group (PcG) proteins are a family of chromatin regulators and critical for the maintenance of cellular identity. The PcG machinery can be categorized into at least three multi-protein complexes, namely Polycomb Repressive Complex 1 (PRC1), PRC2, and Polycomb Repressive DeUBiquitinase (PR-DUB). Their deregulation has been associated with human cancer initiation and progression. Here we review the updated understanding for PcG proteins in transcription regulation and DNA damage repair and highlight increasing links to the hallmarks in cancer. Accordingly, we discuss some of the recent advances in drug development or strategies against cancers caused by the gain or loss of PcG functions.
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21
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Sabit H, Abdel-Ghany S, Tombuloglu H, Cevik E, Alqosaibi A, Almulhim F, Al-Muhanaa A. New insights on CRISPR/Cas9-based therapy for breast Cancer. Genes Environ 2021; 43:15. [PMID: 33926574 PMCID: PMC8082964 DOI: 10.1186/s41021-021-00188-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/12/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR/Cas9 has revolutionized genome-editing techniques in various biological fields including human cancer research. Cancer is a multi-step process that encompasses the accumulation of mutations that result in the hallmark of the malignant state. The goal of cancer research is to identify these mutations and correlate them with the underlying tumorigenic process. Using CRISPR/Cas9 tool, specific mutations responsible for cancer initiation and/or progression could be corrected at least in animal models as a first step towards translational applications. In the present article, we review various novel strategies that employed CRISPR/Cas9 to treat breast cancer in both in vitro and in vivo systems.
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Affiliation(s)
- Hussein Sabit
- Department of Genetics, Institute for Medical Research and Consultations, Imam Abdulrahman Bin Faisal University, P. O. Box: 1982, Dammam, 31441, Saudi Arabia.
| | - Shaimaa Abdel-Ghany
- Department of Environmental Biotechnology, College of Biotechnology, Misr University for Science and Technology, P. O. Box 77, Giza, Egypt
| | - Huseyin Tombuloglu
- Department of Genetics, Institute for Medical Research and Consultations, Imam Abdulrahman Bin Faisal University, P. O. Box: 1982, Dammam, 31441, Saudi Arabia
| | - Emre Cevik
- Department of Genetics, Institute for Medical Research and Consultations, Imam Abdulrahman Bin Faisal University, P. O. Box: 1982, Dammam, 31441, Saudi Arabia
| | - Amany Alqosaibi
- Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University, P. O. 4 Box, Dammam, 1982, Saudi Arabia
| | - Fatma Almulhim
- Breast Imaging Division, KFHU, Imam Abdulrahman Bin Faisal University, P. O. 4 Box, Dammam, 1982, Saudi Arabia
| | - Afnan Al-Muhanaa
- Breast Imaging Division, KFHU, Imam Abdulrahman Bin Faisal University, P. O. 4 Box, Dammam, 1982, Saudi Arabia
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22
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Huseyin MK, Klose RJ. Live-cell single particle tracking of PRC1 reveals a highly dynamic system with low target site occupancy. Nat Commun 2021; 12:887. [PMID: 33563969 PMCID: PMC7873255 DOI: 10.1038/s41467-021-21130-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 01/13/2021] [Indexed: 01/04/2023] Open
Abstract
Polycomb repressive complex 1 (PRC1) is an essential chromatin-based repressor of gene transcription. How PRC1 engages with chromatin to identify its target genes and achieve gene repression remains poorly defined, representing a major hurdle to our understanding of Polycomb system function. Here, we use genome engineering and single particle tracking to dissect how PRC1 binds to chromatin in live mouse embryonic stem cells. We observe that PRC1 is highly dynamic, with only a small fraction stably interacting with chromatin. By integrating subunit-specific dynamics, chromatin binding, and abundance measurements, we discover that PRC1 exhibits low occupancy at target sites. Furthermore, we employ perturbation approaches to uncover how specific components of PRC1 define its kinetics and chromatin binding. Together, these discoveries provide a quantitative understanding of chromatin binding by PRC1 in live cells, suggesting that chromatin modification, as opposed to PRC1 complex occupancy, is central to gene repression.
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Affiliation(s)
- Miles K Huseyin
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
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23
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Pyziak K, Sroka-Porada A, Rzymski T, Dulak J, Łoboda A. Potential of enhancer of zeste homolog 2 inhibitors for the treatment of SWI/SNF mutant cancers and tumor microenvironment modulation. Drug Dev Res 2021; 82:730-753. [PMID: 33565092 DOI: 10.1002/ddr.21796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 12/17/2022]
Abstract
Enhancer of zeste homolog 2 (EZH2), a catalytic component of polycomb repressive complex 2 (PRC2), is commonly overexpressed or mutated in many cancer types, both of hematological and solid nature. Till now, plenty of EZH2 small molecule inhibitors have been developed and some of them have already been tested in clinical trials. Most of these inhibitors, however, are effective only in limited cases in the context of EZH2 gain-of-function mutated tumors such as lymphomas. Other cancer types with aberrant EZH2 expression and function require alternative approaches for successful treatment. One possibility is to exploit synthetic lethal strategy, which is based on the phenomenon that concurrent loss of two genes is detrimental but the deletion of either of them leaves cell viable. In the context of EZH2/PRC2, the most promising synthetic lethal target seems to be SWItch/Sucrose Non-Fermentable chromatin remodeling complex (SWI/SNF), which is known to counteract PRC2 functions. SWI/SNF is heavily involved in carcinogenesis and its subunits have been found mutated in approximately 20% of tumors of different kinds. In the current review, we summarize the existing knowledge of synthetic lethal relationships between EZH2/PRC2 and components of the SWI/SNF complex and discuss in detail the potential application of existing EZH2 inhibitors in cancer patients harboring mutations in SWI/SNF proteins. We also highlight recent discoveries of EZH2 involvement in tumor microenvironment regulation and consequences for future therapies. Although clinical studies are limited, the fundamental research might help to understand which patients are most likely to benefit from therapies using EZH2 inhibitors.
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Affiliation(s)
- Karolina Pyziak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.,Biology R&D, Ryvu Therapeutics S.A., Kraków, Poland
| | | | | | - Józef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Agnieszka Łoboda
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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24
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Cottone L, Cribbs AP, Khandelwal G, Wells G, Ligammari L, Philpott M, Tumber A, Lombard P, Hookway ES, Szommer T, Johansson C, Brennan PE, Pillay N, Jenner RG, Oppermann U, Flanagan AM. Inhibition of Histone H3K27 Demethylases Inactivates Brachyury (TBXT) and Promotes Chordoma Cell Death. Cancer Res 2020; 80:4540-4551. [PMID: 32855205 DOI: 10.1158/0008-5472.can-20-1387] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/08/2020] [Accepted: 08/19/2020] [Indexed: 11/16/2022]
Abstract
Expression of the transcription factor brachyury (TBXT) is normally restricted to the embryo, and its silencing is epigenetically regulated. TBXT promotes mesenchymal transition in a subset of common carcinomas, and in chordoma, a rare cancer showing notochordal differentiation, TBXT acts as a putative oncogene. We hypothesized that TBXT expression is controlled through epigenetic inhibition to promote chordoma cell death. Screening of five human chordoma cell lines revealed that pharmacologic inhibition of the histone 3 lysine 27 demethylases KDM6A (UTX) and KDM6B (JMJD3) leads to cell death. This effect was phenocopied by dual genetic inactivation of KDM6A/B using CRISPR/Cas9. Inhibition of KDM6A/B with a novel compound KDOBA67 led to a genome-wide increase in repressive H3K27me3 marks with concomitant reduction in active H3K27ac, H3K9ac, and H3K4me3 marks. TBXT was a KDM6A/B target gene, and chromatin changes at TBXT following KDOBA67 treatment were associated with a reduction in TBXT protein levels in all models tested, including primary patient-derived cultures. In all models tested, KDOBA67 treatment downregulated expression of a network of transcription factors critical for chordoma survival and upregulated pathways dominated by ATF4-driven stress and proapoptotic responses. Blocking the AFT4 stress response did not prevent suppression of TBXT and induction of cell death, but ectopic overexpression of TBXT increased viability, therefore implicating TBXT as a potential therapeutic target of H3K27 demethylase inhibitors in chordoma. Our work highlights how knowledge of normal processes in fetal development can provide insight into tumorigenesis and identify novel therapeutic approaches. SIGNIFICANCE: Pharmacologic inhibition of H3K27-demethylases in human chordoma cells promotes epigenetic silencing of oncogenic TBXT, alters gene networks critical to survival, and represents a potential novel therapy.
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Affiliation(s)
- Lucia Cottone
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Adam P Cribbs
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Garima Khandelwal
- Department of Cancer Biology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Graham Wells
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Lorena Ligammari
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Martin Philpott
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Anthony Tumber
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | - Patrick Lombard
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Edward S Hookway
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Tamas Szommer
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | - Catrine Johansson
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom
| | - Paul E Brennan
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | - Nischalan Pillay
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
| | - Richard G Jenner
- Department of Cancer Biology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Udo Oppermann
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
- FRIAS - Freiburg Institute of Advanced Studies, University of Freiburg, Freiburg, Germany
| | - Adrienne M Flanagan
- Department of Pathology, UCL Cancer Institute, University College London, London, United Kingdom.
- Department of Histopathology, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom
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25
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Gonçalves CS, Le Boiteux E, Arnaud P, Costa BM. HOX gene cluster (de)regulation in brain: from neurodevelopment to malignant glial tumours. Cell Mol Life Sci 2020; 77:3797-3821. [PMID: 32239260 PMCID: PMC11105007 DOI: 10.1007/s00018-020-03508-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/10/2020] [Accepted: 03/17/2020] [Indexed: 12/19/2022]
Abstract
HOX genes encode a family of evolutionarily conserved homeodomain transcription factors that are crucial both during development and adult life. In humans, 39 HOX genes are arranged in four clusters (HOXA, B, C, and D) in chromosomes 7, 17, 12, and 2, respectively. During embryonic development, particular epigenetic states accompany their expression along the anterior-posterior body axis. This tightly regulated temporal-spatial expression pattern reflects their relative chromosomal localization, and is critical for normal embryonic brain development when HOX genes are mainly expressed in the hindbrain and mostly absent in the forebrain region. Epigenetic marks, mostly polycomb-associated, are dynamically regulated at HOX loci and regulatory regions to ensure the finely tuned HOX activation and repression, highlighting a crucial epigenetic plasticity necessary for homeostatic development. HOX genes are essentially absent in healthy adult brain, whereas they are detected in malignant brain tumours, namely gliomas, where HOX genes display critical roles by regulating several hallmarks of cancer. Here, we review the major mechanisms involved in HOX genes (de)regulation in the brain, from embryonic to adult stages, in physiological and oncologic conditions. We focus particularly on the emerging causes of HOX gene deregulation in glioma, as well as on their functional and clinical implications.
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Affiliation(s)
- Céline S Gonçalves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Elisa Le Boiteux
- Université Clermont Auvergne, CNRS, INSERM-iGReD, Clermont-Ferrand, France
| | - Philippe Arnaud
- Université Clermont Auvergne, CNRS, INSERM-iGReD, Clermont-Ferrand, France
| | - Bruno M Costa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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26
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Abstract
Predicting regulatory potential from primary DNA sequences or transcription factor binding patterns is not possible. However, the annotation of the genome by chromatin proteins, histone modifications, and differential compaction is largely sufficient to reveal the locations of genes and their differential activity states. The Polycomb Group (PcG) and Trithorax Group (TrxG) proteins are the central players in this cell type-specific chromatin organization. PcG function was originally viewed as being solely repressive and irreversible, as observed at the homeotic loci in flies and mammals. However, it is now clear that modular and reversible PcG function is essential at most developmental genes. Focusing mainly on recent advances, we review evidence for how PcG and TrxG patterns change dynamically during cell type transitions. The ability to implement cell type-specific transcriptional programming with exquisite fidelity is essential for normal development.
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Affiliation(s)
- Mitzi I Kuroda
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Hyuckjoon Kang
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Sandip De
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Judith A Kassis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
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27
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Ridenour JB, Möller M, Freitag M. Polycomb Repression without Bristles: Facultative Heterochromatin and Genome Stability in Fungi. Genes (Basel) 2020; 11:E638. [PMID: 32527036 PMCID: PMC7348808 DOI: 10.3390/genes11060638] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 02/06/2023] Open
Abstract
Genome integrity is essential to maintain cellular function and viability. Consequently, genome instability is frequently associated with dysfunction in cells and associated with plant, animal, and human diseases. One consequence of relaxed genome maintenance that may be less appreciated is an increased potential for rapid adaptation to changing environments in all organisms. Here, we discuss evidence for the control and function of facultative heterochromatin, which is delineated by methylation of histone H3 lysine 27 (H3K27me) in many fungi. Aside from its relatively well understood role in transcriptional repression, accumulating evidence suggests that H3K27 methylation has an important role in controlling the balance between maintenance and generation of novelty in fungal genomes. We present a working model for a minimal repressive network mediated by H3K27 methylation in fungi and outline challenges for future research.
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Affiliation(s)
| | | | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis OR 97331, USA; (J.B.R.); (M.M.)
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28
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Understanding the interplay between CpG island-associated gene promoters and H3K4 methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194567. [PMID: 32360393 PMCID: PMC7294231 DOI: 10.1016/j.bbagrm.2020.194567] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/24/2020] [Accepted: 04/22/2020] [Indexed: 02/07/2023]
Abstract
The precise regulation of gene transcription is required to establish and maintain cell type-specific gene expression programs during multicellular development. In addition to transcription factors, chromatin, and its chemical modification, play a central role in regulating gene expression. In vertebrates, DNA is pervasively methylated at CG dinucleotides, a modification that is repressive to transcription. However, approximately 70% of vertebrate gene promoters are associated with DNA elements called CpG islands (CGIs) that are refractory to DNA methylation. CGIs integrate the activity of a range of chromatin-regulating factors that can post-translationally modify histones and modulate gene expression. This is exemplified by the trimethylation of histone H3 at lysine 4 (H3K4me3), which is enriched at CGI-associated gene promoters and correlates with transcriptional activity. Through studying H3K4me3 at CGIs it has become clear that CGIs shape the distribution of H3K4me3 and, in turn, H3K4me3 influences the chromatin landscape at CGIs. Here we will discuss our understanding of the emerging relationship between CGIs, H3K4me3, and gene expression.
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29
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Godfrey L, Crump NT, O'Byrne S, Lau IJ, Rice S, Harman JR, Jackson T, Elliott N, Buck G, Connor C, Thorne R, Knapp DJHF, Heidenreich O, Vyas P, Menendez P, Inglott S, Ancliff P, Geng H, Roberts I, Roy A, Milne TA. H3K79me2/3 controls enhancer-promoter interactions and activation of the pan-cancer stem cell marker PROM1/CD133 in MLL-AF4 leukemia cells. Leukemia 2020; 35:90-106. [PMID: 32242051 PMCID: PMC7787973 DOI: 10.1038/s41375-020-0808-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/12/2020] [Accepted: 03/18/2020] [Indexed: 02/06/2023]
Abstract
MLL gene rearrangements (MLLr) are a common cause of aggressive, incurable acute lymphoblastic leukemias (ALL) in infants and children, most of which originate in utero. The most common MLLr produces an MLL-AF4 fusion protein. MLL-AF4 promotes leukemogenesis by activating key target genes, mainly through recruitment of DOT1L and increased histone H3 lysine-79 methylation (H3K79me2/3). One key MLL-AF4 target gene is PROM1, which encodes CD133 (Prominin-1). CD133 is a pentaspan transmembrane glycoprotein that represents a potential pan-cancer target as it is found on multiple cancer stem cells. Here we demonstrate that aberrant PROM1/CD133 expression is essential for leukemic cell growth, mediated by direct binding of MLL-AF4. Activation is controlled by an intragenic H3K79me2/3 enhancer element (KEE) leading to increased enhancer–promoter interactions between PROM1 and the nearby gene TAPT1. This dual locus regulation is reflected in a strong correlation of expression in leukemia. We find that in PROM1/CD133 non-expressing cells, the PROM1 locus is repressed by polycomb repressive complex 2 (PRC2) binding, associated with reduced expression of TAPT1, partially due to loss of interactions with the PROM1 locus. Together, these results provide the first detailed analysis of PROM1/CD133 regulation that explains CD133 expression in MLLr ALL.
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Affiliation(s)
- Laura Godfrey
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas T Crump
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Sorcha O'Byrne
- Department of Paediatrics, University of Oxford, Oxford, UK
| | - I-Jun Lau
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Siobhan Rice
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Joe R Harman
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Thomas Jackson
- Department of Paediatrics, University of Oxford, Oxford, UK
| | | | - Gemma Buck
- Department of Paediatrics, University of Oxford, Oxford, UK
| | | | - Ross Thorne
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - David J H F Knapp
- MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Olaf Heidenreich
- Princess Maxima Centrum for Pediatric Oncology, Utrecht, The Netherlands.,Wolfson Childhood Cancer Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | - Paresh Vyas
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,Department of Haematology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Pablo Menendez
- Josep Carreras Leukemia Research Institute, Barcelona, Spain.,Institucio Catalana of Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Centro de Investigación Biomédica en Red en cancer (CIBERONC)-ISCIII, Barcelona, Spain
| | - Sarah Inglott
- Great Ormond Street Hospital for Children, London, UK
| | | | - Huimin Geng
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Irene Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,Department of Paediatrics, University of Oxford, Oxford, UK
| | - Anindita Roy
- Department of Paediatrics, University of Oxford, Oxford, UK.
| | - Thomas A Milne
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, NIHR Oxford Biomedical Research Centre Haematology Theme, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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30
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Blackledge NP, Fursova NA, Kelley JR, Huseyin MK, Feldmann A, Klose RJ. PRC1 Catalytic Activity Is Central to Polycomb System Function. Mol Cell 2020; 77:857-874.e9. [PMID: 31883950 PMCID: PMC7033600 DOI: 10.1016/j.molcel.2019.12.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/21/2019] [Accepted: 12/02/2019] [Indexed: 01/01/2023]
Abstract
The Polycomb repressive system is an essential chromatin-based regulator of gene expression. Despite being extensively studied, how the Polycomb system selects its target genes is poorly understood, and whether its histone-modifying activities are required for transcriptional repression remains controversial. Here, we directly test the requirement for PRC1 catalytic activity in Polycomb system function. To achieve this, we develop a conditional mutation system in embryonic stem cells that completely removes PRC1 catalytic activity. Using this system, we demonstrate that catalysis by PRC1 drives Polycomb chromatin domain formation and long-range chromatin interactions. Furthermore, we show that variant PRC1 complexes with DNA-binding activities occupy target sites independently of PRC1 catalytic activity, providing a putative mechanism for Polycomb target site selection. Finally, we discover that Polycomb-mediated gene repression requires PRC1 catalytic activity. Together these discoveries provide compelling evidence that PRC1 catalysis is central to Polycomb system function and gene regulation.
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Affiliation(s)
- Neil P Blackledge
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK
| | - Nadezda A Fursova
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK
| | - Jessica R Kelley
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK
| | - Miles K Huseyin
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK
| | - Angelika Feldmann
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, UK.
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31
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Hugues A, Jacobs CS, Roudier F. Mitotic Inheritance of PRC2-Mediated Silencing: Mechanistic Insights and Developmental Perspectives. FRONTIERS IN PLANT SCIENCE 2020; 11:262. [PMID: 32211012 PMCID: PMC7075419 DOI: 10.3389/fpls.2020.00262] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 02/19/2020] [Indexed: 05/20/2023]
Abstract
Maintenance of gene repression by Polycomb Repressive Complex 2 (PRC2) that catalyzes the trimethylation of histone H3 at lysine 27 (H3K27me3) is integral to the orchestration of developmental programs in most multicellular eukaryotes. Faithful inheritance of H3K27me3 patterns across replication ensures the stability of PRC2-mediated transcriptional silencing over cell generations, thereby safeguarding cellular identities. In this review, we discuss the molecular and mechanistic principles that underlie H3K27me3 restoration after the passage of the replication fork, considering recent advances in different model systems. In particular, we aim at emphasizing parallels and differences between plants and other organisms, focusing on the recycling of parental histones and the replenishment of H3K27me3 patterns post-replication thanks to the remarkable properties of the PRC2 complex. We then discuss the necessity for fine-tuning this genuine epigenetic memory system so as to allow for cell fate and developmental transitions. We highlight recent insights showing that genome-wide destabilization of the H3K27me3 landscape during chromatin replication participates in achieving this flexible stability and provides a window of opportunity for subtle transcriptional reprogramming.
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Affiliation(s)
- Alice Hugues
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Université de Lyon, Lyon, France
- Master de Biologie, École Normale Supérieure de Lyon, Université Claude Bernard Lyon I, Université de Lyon, Lyon, France
| | - Chean Sern Jacobs
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Université de Lyon, Lyon, France
| | - François Roudier
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, INRIA, Université de Lyon, Lyon, France
- *Correspondence: François Roudier,
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32
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Court F, Le Boiteux E, Fogli A, Müller-Barthélémy M, Vaurs-Barrière C, Chautard E, Pereira B, Biau J, Kemeny JL, Khalil T, Karayan-Tapon L, Verrelle P, Arnaud P. Transcriptional alterations in glioma result primarily from DNA methylation-independent mechanisms. Genome Res 2019; 29:1605-1621. [PMID: 31533980 PMCID: PMC6771409 DOI: 10.1101/gr.249219.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/27/2019] [Indexed: 02/06/2023]
Abstract
In cancer cells, aberrant DNA methylation is commonly associated with transcriptional alterations, including silencing of tumor suppressor genes. However, multiple epigenetic mechanisms, including polycomb repressive marks, contribute to gene deregulation in cancer. To dissect the relative contribution of DNA methylation–dependent and –independent mechanisms to transcriptional alterations at CpG island/promoter-associated genes in cancer, we studied 70 samples of adult glioma, a widespread type of brain tumor, classified according to their isocitrate dehydrogenase (IDH1) mutation status. We found that most transcriptional alterations in tumor samples were DNA methylation–independent. Instead, altered histone H3 trimethylation at lysine 27 (H3K27me3) was the predominant molecular defect at deregulated genes. Our results also suggest that the presence of a bivalent chromatin signature at CpG island promoters in stem cells predisposes not only to hypermethylation, as widely documented, but more generally to all types of transcriptional alterations in transformed cells. In addition, the gene expression strength in healthy brain cells influences the choice between DNA methylation- and H3K27me3-associated silencing in glioma. Highly expressed genes were more likely to be repressed by H3K27me3 than by DNA methylation. Our findings support a model in which altered H3K27me3 dynamics, more specifically defects in the interplay between polycomb protein complexes and the brain-specific transcriptional machinery, is the main cause of transcriptional alteration in glioma cells. Our study provides the first comprehensive description of epigenetic changes in glioma and their relative contribution to transcriptional changes. It may be useful for the design of drugs targeting cancer-related epigenetic defects.
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Affiliation(s)
- Franck Court
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France
| | - Elisa Le Boiteux
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France
| | - Anne Fogli
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France.,Biochemistry and Molecular Biology Department, Clermont-Ferrand Hospital, Clermont-Ferrand 63003, France
| | - Mélanie Müller-Barthélémy
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France.,Pathology Department, Jean Perrin Center, Clermont-Ferrand 63011, France
| | - Catherine Vaurs-Barrière
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France
| | - Emmanuel Chautard
- Pathology Department, Jean Perrin Center, Clermont-Ferrand 63011, France.,Université Clermont Auvergne, INSERM, U1240 IMoST, Clermont-Ferrand 63011, France
| | - Bruno Pereira
- Biostatistics Department, Délégation à la Recherche Clinique et à l'Innovation, Clermont-Ferrand Hospital, Clermont-Ferrand 63003, France
| | - Julian Biau
- Université Clermont Auvergne, INSERM, U1240 IMoST, Clermont-Ferrand 63011, France.,Radiotherapy Department, Jean Perrin Center, Clermont-Ferrand 63011, France
| | - Jean-Louis Kemeny
- Pathology Department, Université Clermont Auvergne and Clermont-Ferrand Hospital, Clermont-Ferrand 63003, France
| | - Toufic Khalil
- Department of Neurosurgery, Clermont-Ferrand Hospital, Clermont-Ferrand 63003, France
| | - Lucie Karayan-Tapon
- INSERM, U1084, Poitiers 86021, France.,Poitiers University, Poitiers 86000, France.,Department of Cancer Biology, Poitiers Hospital, Poitiers 86021, France
| | - Pierre Verrelle
- INSERM, U1196 CNRS UMR9187, Curie Institute, Orsay 91405, France.,Radiotherapy Department Curie Institute, Paris 75005, France.,Université Clermont Auvergne, Clermont-Ferrand 63000, France
| | - Philippe Arnaud
- Laboratoire Génétique Reproduction et Développement (GReD), Université Clermont Auvergne, CNRS, INSERM, BP 38, Clermont-Ferrand 63001, France
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33
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Denisenko O, Mar D, Trawczynski M, Bomsztyk K. Chromatin changes trigger laminin genes dysregulation in aging kidneys. Aging (Albany NY) 2019; 10:1133-1145. [PMID: 29846172 PMCID: PMC5990391 DOI: 10.18632/aging.101453] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/15/2018] [Indexed: 12/13/2022]
Abstract
Dysregulation of gene expression is a hallmark of aging. We examined epigenetic mechanisms that mediate aberrant expression of laminin genes in aging rat kidneys. In old animals, no alterations were found in the levels of abundant laminin mRNAs, whereas Lama3, b3, and c2 transcripts were increased compared to young animals. Lamc2 showed the strongest changes at the mRNA and protein levels. Lamc2 upregulation was transcriptional, as indicated by the elevated RNA polymerase II density at the gene. Furthermore, aging is associated with the loss of H3K27m3 and 5mC silencing modifications at the Lamc2 gene. Western blot analysis revealed no changes in cellular levels of H3K27m3 and cognate enzyme Ezh2 in old kidneys. Thus, the decrease in H3K27m3 at Lamc2 resulted from the re-distribution of this mark among genomic sites. Studies in kidney cells in vitro showed that reducing H3K27m3 density with Ezh2 inhibitor had no effect on Lamc2 expression, suggesting that this modification plays little role in gene upregulation in aging kidney. In contrast, treatment with DNA methylation inhibitor 2'-deoxy-5-azacytidine was sufficient to upregulate Lamc2 gene. We suggest that the loss of 5mC at silenced laminin genes drives their de-repression during aging, contributing to the age-related decline in renal function.
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Affiliation(s)
- Oleg Denisenko
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Daniel Mar
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | | | - Karol Bomsztyk
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
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34
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Sneppen K, Ringrose L. Theoretical analysis of Polycomb-Trithorax systems predicts that poised chromatin is bistable and not bivalent. Nat Commun 2019; 10:2133. [PMID: 31086177 PMCID: PMC6513952 DOI: 10.1038/s41467-019-10130-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 04/12/2019] [Indexed: 12/15/2022] Open
Abstract
Polycomb (PcG) and Trithorax (TrxG) group proteins give stable epigenetic memory of silent and active gene expression states, but also allow poised states in pluripotent cells. Here we systematically address the relationship between poised, active and silent chromatin, by integrating 73 publications on PcG/TrxG biochemistry into a mathematical model comprising 144 nucleosome modification states and 8 enzymatic reactions. Our model predicts that poised chromatin is bistable and not bivalent. Bivalent chromatin, containing opposing active and silent modifications, is present as an unstable background population in all system states, and different subtypes co-occur with active and silent chromatin. In contrast, bistability, in which the system switches frequently between stable active and silent states, occurs under a wide range of conditions at the transition between monostable active and silent system states. By proposing that bistability and not bivalency is associated with poised chromatin, this work has implications for understanding the molecular nature of pluripotency. Polycomb and Trithorax group proteins regulate silent and active gene expression states, but also allow poised states in pluripotent cells. Here the authors present a mathematical model that integrates data on Polycomb/ Trithorax biochemistry into a single coherent framework which predicts that poised chromatin is not bivalent as previously proposed, but is bistable, meaning that the system switches frequently between stable active and silent states.
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Affiliation(s)
- Kim Sneppen
- Center for Models of Life, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen, Denmark.
| | - Leonie Ringrose
- Integrated Research Institute for Life Sciences, Humboldt-Universität zu Berlin, Philippstrasse 13, Haus 22, 10115, Berlin, Germany.
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35
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Loubiere V, Martinez AM, Cavalli G. Cell Fate and Developmental Regulation Dynamics by Polycomb Proteins and 3D Genome Architecture. Bioessays 2019; 41:e1800222. [PMID: 30793782 DOI: 10.1002/bies.201800222] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/22/2018] [Indexed: 12/14/2022]
Abstract
Targeted transitions in chromatin states at thousands of genes are essential drivers of eukaryotic development. Therefore, understanding the in vivo dynamics of epigenetic regulators is crucial for deciphering the mechanisms underpinning cell fate decisions. This review illustrates how, in addition to its cell memory function, the Polycomb group of transcriptional regulators orchestrates temporal, cell and tissue-specific expression of master genes during development. These highly sophisticated developmental transitions are dependent on the context- and tissue-specific assembly of the different types of Polycomb Group (PcG) complexes, which regulates their targeting and/or activities on chromatin. Here, an overview is provided of how PcG complexes function at multiple scales to regulate transcription, local chromatin environment, and higher order structures that support normal differentiation and are perturbed in tumorigenesis.
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Affiliation(s)
- Vincent Loubiere
- Institute of Human Genetics, UMR 9002, CNRS and University of Montpellier, 34396, Montpellier, France
| | - Anne-Marie Martinez
- Institute of Human Genetics, UMR 9002, CNRS and University of Montpellier, 34396, Montpellier, France
| | - Giacomo Cavalli
- Institute of Human Genetics, UMR 9002, CNRS and University of Montpellier, 34396, Montpellier, France
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36
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Heyn P, Logan CV, Fluteau A, Challis RC, Auchynnikava T, Martin CA, Marsh JA, Taglini F, Kilanowski F, Parry DA, Cormier-Daire V, Fong CT, Gibson K, Hwa V, Ibáñez L, Robertson SP, Sebastiani G, Rappsilber J, Allshire RC, Reijns MAM, Dauber A, Sproul D, Jackson AP. Gain-of-function DNMT3A mutations cause microcephalic dwarfism and hypermethylation of Polycomb-regulated regions. Nat Genet 2019; 51:96-105. [PMID: 30478443 PMCID: PMC6520989 DOI: 10.1038/s41588-018-0274-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 10/10/2018] [Indexed: 12/29/2022]
Abstract
DNA methylation and Polycomb are key factors in the establishment of vertebrate cellular identity and fate. Here we report de novo missense mutations in DNMT3A, which encodes the DNA methyltransferase DNMT3A. These mutations cause microcephalic dwarfism, a hypocellular disorder of extreme global growth failure. Substitutions in the PWWP domain abrogate binding to the histone modifications H3K36me2 and H3K36me3, and alter DNA methylation in patient cells. Polycomb-associated DNA methylation valleys, hypomethylated domains encompassing developmental genes, become methylated with concomitant depletion of H3K27me3 and H3K4me3 bivalent marks. Such de novo DNA methylation occurs during differentiation of Dnmt3aW326R pluripotent cells in vitro, and is also evident in Dnmt3aW326R/+ dwarf mice. We therefore propose that the interaction of the DNMT3A PWWP domain with H3K36me2 and H3K36me3 normally limits DNA methylation of Polycomb-marked regions. Our findings implicate the interplay between DNA methylation and Polycomb at key developmental regulators as a determinant of organism size in mammals.
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Affiliation(s)
- Patricia Heyn
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Clare V Logan
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Adeline Fluteau
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Rachel C Challis
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Tatsiana Auchynnikava
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Carol-Anne Martin
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Joseph A Marsh
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Francesca Taglini
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
- Edinburgh Cancer Research Centre, IGMM, University of Edinburgh, Edinburgh, UK
| | - Fiona Kilanowski
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - David A Parry
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Valerie Cormier-Daire
- Department of Medical Genetics, INSERM UMR 1163, Université Paris-Descartes-Sorbonne Paris Cité, Institut Imagine, AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| | - Chin-To Fong
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Kate Gibson
- Genetic Health Service New Zealand, Christchurch Hospital, Christchurch, New Zealand
| | - Vivian Hwa
- Cincinnati Center for Growth Disorders, Division of Endocrinology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lourdes Ibáñez
- Department of Endocrinology, Pediatric Research Institute Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Madrid, Spain
| | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Giorgia Sebastiani
- Neonatology Unit, Hospital Clinic-Maternitat, ICGON, BCNatal, University of Barcelona, Barcelona, Spain
| | - Juri Rappsilber
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Robin C Allshire
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Martin A M Reijns
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK
| | - Andrew Dauber
- Cincinnati Center for Growth Disorders, Division of Endocrinology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Endocrinology, Children's National Medical Center, Washington, DC, USA
| | - Duncan Sproul
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK.
- Edinburgh Cancer Research Centre, IGMM, University of Edinburgh, Edinburgh, UK.
| | - Andrew P Jackson
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, UK.
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37
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Alhaj Abed J, Ghotbi E, Ye P, Frolov A, Benes J, Jones RS. De novo recruitment of Polycomb-group proteins in Drosophila embryos. Development 2018; 145:dev.165027. [PMID: 30389849 DOI: 10.1242/dev.165027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 10/29/2018] [Indexed: 12/24/2022]
Abstract
Polycomb-group (PcG)-mediated transcriptional repression of target genes can be delineated into two phases. First, following initial repression of target genes by gene-specific transcription factors, PcG proteins recognize the repressed state and assume control of the genes' repression. Second, once the silenced state is established, PcG proteins may maintain repression through an indefinite number of cell cycles. Little is understood about how PcG proteins initially recognize the repressed state of target genes and the steps leading to de novo establishment of PcG-mediated repression. We describe a genetic system in which a Drosophila PcG target gene, giant (gt), is ubiquitously repressed during early embryogenesis by a maternally expressed transcription factor, and show the temporal recruitment of components of three PcG protein complexes: PhoRC, PRC1 and PRC2. We show that de novo PcG recruitment follows a temporal hierarchy in which PhoRC stably localizes at the target gene at least 1 h before stable recruitment of PRC2 and concurrent trimethylation of histone H3 at lysine 27 (H3K27me3). The presence of PRC2 and increased levels of H3K27me3 are found to precede stable binding by PRC1.
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Affiliation(s)
- Jumana Alhaj Abed
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Elnaz Ghotbi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Piao Ye
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Alexander Frolov
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Judith Benes
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Richard S Jones
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
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38
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Du J, Kirk B, Zeng J, Ma J, Wang Q. Three classes of response elements for human PRC2 and MLL1/2-Trithorax complexes. Nucleic Acids Res 2018; 46:8848-8864. [PMID: 29992232 PMCID: PMC6158500 DOI: 10.1093/nar/gky595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 12/15/2022] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) proteins are essential for maintaining epigenetic memory in both embryonic stem cells and differentiated cells. To date, how they are localized to hundreds of specific target genes within a vertebrate genome had remained elusive. Here, by focusing on short cis-acting DNA elements of single functions, we discovered three classes of response elements in human genome: Polycomb response elements (PREs), Trithorax response elements (TREs) and Polycomb/Trithorax response elements (P/TREs). In particular, the four PREs (PRE14, 29, 39 and 48) are the first set of, to our knowledge, bona fide vertebrate PREs ever discovered, while many previously reported Drosophila or vertebrate PREs are likely P/TREs. We further demonstrated that YY1 and CpG islands are specifically enriched in the four TREs (PRE30, 41, 44 and 55), but not in the PREs. The three classes of response elements as unraveled in this study should guide further global investigation and open new doors for a deeper understanding of PcG and TrxG mechanisms in vertebrates.
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Affiliation(s)
- Junqing Du
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Brian Kirk
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jia Zeng
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jianpeng Ma
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - Qinghua Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Morgan MD, Marioni JC. CpG island composition differences are a source of gene expression noise indicative of promoter responsiveness. Genome Biol 2018; 19:81. [PMID: 29945659 PMCID: PMC6020341 DOI: 10.1186/s13059-018-1461-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/04/2018] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Population phenotypic variation can arise from genetic differences between individuals, or from cellular heterogeneity in an isogenic group of cells or organisms. The emergence of gene expression differences between genetically identical cells is referred to as gene expression noise, the sources of which are not well understood. RESULTS In this work, by studying gene expression noise between multiple cell lineages and mammalian species, we find consistent evidence of a role for CpG islands as sources of gene expression noise. Variation in noise among CpG island promoters can be partially attributed to differences in island size, in which short islands have noisier gene expression. Building on these findings, we investigate the potential for short CpG islands to act as fast response elements to environmental stimuli. Specifically, we find that these islands are enriched amongst primary response genes in SWI/SNF-independent stimuli, suggesting that expression noise is an indicator of promoter responsiveness. CONCLUSIONS Thus, through the integration of single-cell RNA expression profiling, chromatin landscape and temporal gene expression dynamics, we have uncovered a role for short CpG island promoters as fast response elements.
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Affiliation(s)
- Michael D Morgan
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
| | - John C Marioni
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
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40
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Dimitrova E, Kondo T, Feldmann A, Nakayama M, Koseki Y, Konietzny R, Kessler BM, Koseki H, Klose RJ. FBXL19 recruits CDK-Mediator to CpG islands of developmental genes priming them for activation during lineage commitment. eLife 2018; 7:e37084. [PMID: 29809150 PMCID: PMC5997449 DOI: 10.7554/elife.37084] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 05/26/2018] [Indexed: 01/05/2023] Open
Abstract
CpG islands are gene regulatory elements associated with the majority of mammalian promoters, yet how they regulate gene expression remains poorly understood. Here, we identify FBXL19 as a CpG island-binding protein in mouse embryonic stem (ES) cells and show that it associates with the CDK-Mediator complex. We discover that FBXL19 recruits CDK-Mediator to CpG island-associated promoters of non-transcribed developmental genes to prime these genes for activation during cell lineage commitment. We further show that recognition of CpG islands by FBXL19 is essential for mouse development. Together this reveals a new CpG island-centric mechanism for CDK-Mediator recruitment to developmental gene promoters in ES cells and a requirement for CDK-Mediator in priming these developmental genes for activation during cell lineage commitment.
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Affiliation(s)
- Emilia Dimitrova
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
| | - Takashi Kondo
- Laboratory for Developmental GeneticsRIKEN Center for Integrative Medical SciencesYokohamaJapan
| | | | - Manabu Nakayama
- Department of Technology DevelopmentKazusa DNA Research InstituteKisarazuJapan
| | - Yoko Koseki
- Laboratory for Developmental GeneticsRIKEN Center for Integrative Medical SciencesYokohamaJapan
| | - Rebecca Konietzny
- Nuffield Department of MedicineTDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
| | - Benedikt M Kessler
- Nuffield Department of MedicineTDI Mass Spectrometry Laboratory, Target Discovery Institute, University of OxfordOxfordUnited Kingdom
| | - Haruhiko Koseki
- Laboratory for Developmental GeneticsRIKEN Center for Integrative Medical SciencesYokohamaJapan
- CRESTJapan Science and Technology AgencyKawaguchiJapan
| | - Robert J Klose
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
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41
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Brown DA, Di Cerbo V, Feldmann A, Ahn J, Ito S, Blackledge NP, Nakayama M, McClellan M, Dimitrova E, Turberfield AH, Long HK, King HW, Kriaucionis S, Schermelleh L, Kutateladze TG, Koseki H, Klose RJ. The SET1 Complex Selects Actively Transcribed Target Genes via Multivalent Interaction with CpG Island Chromatin. Cell Rep 2018; 20:2313-2327. [PMID: 28877467 PMCID: PMC5603731 DOI: 10.1016/j.celrep.2017.08.030] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/19/2017] [Accepted: 08/06/2017] [Indexed: 12/24/2022] Open
Abstract
Chromatin modifications and the promoter-associated epigenome are important for the regulation of gene expression. However, the mechanisms by which chromatin-modifying complexes are targeted to the appropriate gene promoters in vertebrates and how they influence gene expression have remained poorly defined. Here, using a combination of live-cell imaging and functional genomics, we discover that the vertebrate SET1 complex is targeted to actively transcribed gene promoters through CFP1, which engages in a form of multivalent chromatin reading that involves recognition of non-methylated DNA and histone H3 lysine 4 trimethylation (H3K4me3). CFP1 defines SET1 complex occupancy on chromatin, and its multivalent interactions are required for the SET1 complex to place H3K4me3. In the absence of CFP1, gene expression is perturbed, suggesting that normal targeting and function of the SET1 complex are central to creating an appropriately functioning vertebrate promoter-associated epigenome. The CFP1/SET1 complex engages in dynamic and stable chromatin-binding events CFP1 uses multivalent chromatin interactions to select active CpG island promoters SET1A occupancy at CpG island promoters is predominately defined by CFP1 CFP1 targets SET1 to shape promoter-associated H3K4me3 and gene expression
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Affiliation(s)
- David A Brown
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Vincenzo Di Cerbo
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Angelika Feldmann
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Jaewoo Ahn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Shinsuke Ito
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), 1-7-2 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Neil P Blackledge
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Manabu Nakayama
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), 1-7-2 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Michael McClellan
- Ludwig Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Emilia Dimitrova
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | | | - Hannah K Long
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Hamish W King
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Skirmantas Kriaucionis
- Ludwig Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Haruhiko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), 1-7-2 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
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42
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Court F, Arnaud P. An annotated list of bivalent chromatin regions in human ES cells: a new tool for cancer epigenetic research. Oncotarget 2018; 8:4110-4124. [PMID: 27926531 PMCID: PMC5354816 DOI: 10.18632/oncotarget.13746] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/23/2016] [Indexed: 12/12/2022] Open
Abstract
CpG islands (CGI) marked by bivalent chromatin in stem cells are believed to be more prone to aberrant DNA methylation in tumor cells. The robustness and genome-wide extent of this instructive program in different cancer types remain to be determined. To address this issue we developed a user-friendly approach to integrate the stem cell chromatin signature in customized DNA methylation analyses. We used publicly available ChIP-sequencing datasets of several human embryonic stem cell (hESC) lines to determine the extent of bivalent chromatin genome-wide. We then created annotated lists of high-confidence bivalent, H3K4me3-only and H3K27me3-only chromatin regions. The main features of bivalent regions included localization in CGI/promoters, depletion in retroelements and enrichment in specific histone modifications, including the poorly characterized H3K23me2 mark. Moreover, bivalent promoters could be classified in three clusters based on PRC2 and PolII complexes occupancy. Genes with bivalent promoters of the PRC2-defined cluster displayed the lowest expression upon differentiation. As proof-of-concept, we assessed the DNA methylation pattern of eight types of tumors and confirmed that aberrant cancer-associated DNA hypermethylation preferentially targets CGI characterized by bivalent chromatin in hESCs. We also found that such aberrant DNA hypermethylation affected particularly bivalent CGI/promoters associated with genes that tend to remain repressed upon differentiation. Strikingly, bivalent CGI were the most affected by aberrant DNA hypermethylation in both CpG Island Methylator Phenotype-positive (CIMP+) and CIMP-negative tumors, suggesting that, besides transcriptional silencing in the pre-tumorigenic cells, the bivalent chromatin signature in hESCs is a key determinant of the instructive program for aberrant DNA methylation.
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Affiliation(s)
- Franck Court
- CNRS-UMR 6293, Clermont-Ferrand, 63001, France.,INSERM-U1103, Clermont-Ferrand, 63001, France.,Université Clermont Auvergne, GReD Laboratory, Clermont-Ferrand, 63000, France
| | - Philippe Arnaud
- CNRS-UMR 6293, Clermont-Ferrand, 63001, France.,INSERM-U1103, Clermont-Ferrand, 63001, France.,Université Clermont Auvergne, GReD Laboratory, Clermont-Ferrand, 63000, France
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43
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Wang Z, Gearhart MD, Lee YW, Kumar I, Ramazanov B, Zhang Y, Hernandez C, Lu AY, Neuenkirchen N, Deng J, Jin J, Kluger Y, Neubert TA, Bardwell VJ, Ivanova NB. A Non-canonical BCOR-PRC1.1 Complex Represses Differentiation Programs in Human ESCs. Cell Stem Cell 2018; 22:235-251.e9. [PMID: 29337181 DOI: 10.1016/j.stem.2017.12.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 10/18/2017] [Accepted: 12/02/2017] [Indexed: 11/26/2022]
Abstract
Polycomb group proteins regulate self-renewal and differentiation in many stem cell systems. When assembled into two canonical complexes, PRC1 and PRC2, they sequentially deposit H3K27me3 and H2AK119ub histone marks and establish repressive chromatin, referred to as Polycomb domains. Non-canonical PRC1 complexes retain RING1/RNF2 E3-ubiquitin ligases but have unique sets of accessory subunits. How these non-canonical complexes recognize and regulate their gene targets remains poorly understood. Here, we show that the BCL6 co-repressor (BCOR), a member of the PRC1.1 complex, is critical for maintaining primed pluripotency in human embryonic stem cells (ESCs). BCOR depletion leads to the erosion of Polycomb domains at key developmental loci and the initiation of differentiation along endoderm and mesoderm lineages. The C terminus of BCOR regulates the assembly and targeting of the PRC1.1 complex, while the N terminus contributes to BCOR-PRC1.1 repressor function. Our findings advance understanding of Polycomb targeting and repression in ESCs and could apply broadly across developmental systems.
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Affiliation(s)
- Zheng Wang
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Micah D Gearhart
- Department of Genetics, Cell Biology and Development, University of Minnesota, and the Masonic Cancer Center, Minneapolis, MN 55455, USA
| | - Yu-Wei Lee
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Ishan Kumar
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Bulat Ramazanov
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Yan Zhang
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Charles Hernandez
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Alice Y Lu
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Nils Neuenkirchen
- Department of Cell Biology, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA
| | - Jingjing Deng
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, New York University School of Medicine, New York, NY10016, USA
| | - Jiaqi Jin
- Department of Pathology, Yale University, New Haven, CT 06520, USA
| | - Yuval Kluger
- Department of Pathology, Yale University, New Haven, CT 06520, USA
| | - Thomas A Neubert
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, New York University School of Medicine, New York, NY10016, USA
| | - Vivian J Bardwell
- Department of Genetics, Cell Biology and Development, University of Minnesota, and the Masonic Cancer Center, Minneapolis, MN 55455, USA
| | - Natalia B Ivanova
- Department of Genetics, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University, New Haven, CT 06520, USA.
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44
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Hohenstatt ML, Mikulski P, Komarynets O, Klose C, Kycia I, Jeltsch A, Farrona S, Schubert D. PWWP-DOMAIN INTERACTOR OF POLYCOMBS1 Interacts with Polycomb-Group Proteins and Histones and Regulates Arabidopsis Flowering and Development. THE PLANT CELL 2018; 30:117-133. [PMID: 29330200 PMCID: PMC5810566 DOI: 10.1105/tpc.17.00117] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 11/28/2017] [Accepted: 01/09/2018] [Indexed: 05/10/2023]
Abstract
Polycomb-group (PcG) proteins mediate epigenetic gene regulation by setting H3K27me3 via Polycomb Repressive Complex 2 (PRC2). In plants, it is largely unclear how PcG proteins are recruited to their target genes. Here, we identified the PWWP-DOMAIN INTERACTOR OF POLYCOMBS1 (PWO1) protein, which interacts with all three Arabidopsis thaliana PRC2 histone methyltransferases and is required for maintaining full H3 occupancy at several Arabidopsis genes. PWO1 localizes and recruits CURLY LEAF to nuclear speckles in Nicotiana benthamiana nuclei, suggesting a role in spatial organization of PcG regulation. PWO1 belongs to a gene family with three members having overlapping activities: pwo1 pwo2 pwo3 triple mutants are seedling lethal and show shoot and root meristem arrest, while pwo1 single mutants are early flowering. Interestingly, the PWWP domain of PWO1 confers binding to histones, which is reduced by a point mutation in a highly conserved residue of this domain and blocked by phosphorylation of H3S28. PWO1 carrying this mutation is not able to fully complement the pwo1 pwo2 pwo3 triple mutant, indicating the requirement of this domain for PWO1 in vivo activity. Thus, the PWO family may present a novel class of histone readers that are involved in recruiting PcG proteins to subnuclear domains and in promoting Arabidopsis development.
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Affiliation(s)
| | - Pawel Mikulski
- Institute for Genetics, Heinrich-Heine-University, 40225 Duesseldorf, Germany
- Institute of Biology, Freie Universität, 14195 Berlin, Germany
| | - Olga Komarynets
- Institute for Genetics, Heinrich-Heine-University, 40225 Duesseldorf, Germany
- Université de Genève, 1205 Geneva, Switzerland
| | - Constanze Klose
- Institute for Genetics, Heinrich-Heine-University, 40225 Duesseldorf, Germany
| | - Ina Kycia
- Institute for Biochemistry, University of Stuttgart, 70174 Stuttgart, Germany
| | - Albert Jeltsch
- Institute for Biochemistry, University of Stuttgart, 70174 Stuttgart, Germany
| | - Sara Farrona
- Institute for Genetics, Heinrich-Heine-University, 40225 Duesseldorf, Germany
- Plant and AgriBiosciences Centre, National University Ireland, Galway H91 TK33, Ireland
| | - Daniel Schubert
- Institute for Genetics, Heinrich-Heine-University, 40225 Duesseldorf, Germany
- Institute of Biology, Freie Universität, 14195 Berlin, Germany
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45
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46
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Yung PYK, Elsässer SJ. Evolution of epigenetic chromatin states. Curr Opin Chem Biol 2017; 41:36-42. [PMID: 29078152 DOI: 10.1016/j.cbpa.2017.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/06/2017] [Accepted: 10/03/2017] [Indexed: 01/08/2023]
Abstract
The central dogma of gene expression entails the flow of genetic information from DNA to RNA, then to protein. Decades of studies on epigenetics have characterized an additional layer of information, where epigenetic states help to shape differential utilization of genetic information. Orchestrating conditional gene expressions to elicit a defined phenotype and function, epigenetics states distinguish different cell types or maintain a long-lived memory of past signals. Packaging the genetic information in the nucleus of the eukaryotic cell, chromatin provides a large regulatory repertoire that capacitates the genome to give rise to many distinct epigenomes. We will discuss how reversible, heritable functional annotation mechanisms in chromatin may have evolved from basic chemical diversification of the underlying molecules.
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Affiliation(s)
- Philip Yuk Kwong Yung
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Simon J Elsässer
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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47
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Chica C, Louis A, Roest Crollius H, Colot V, Roudier F. Comparative epigenomics in the Brassicaceae reveals two evolutionarily conserved modes of PRC2-mediated gene regulation. Genome Biol 2017; 18:207. [PMID: 29084582 PMCID: PMC5663038 DOI: 10.1186/s13059-017-1333-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 10/03/2017] [Indexed: 01/05/2023] Open
Abstract
Background Polycomb Repressive Complexes 2 (PRC2) are multi-protein chromatin modifiers that are evolutionarily conserved among eukaryotes and play key roles in the regulation of gene expression, notably through the trimethylation of lysine 27 of histone H3 (H3K27me3). Although PRC2-mediated gene regulation has been studied in many organisms, few studies have explored in depth the evolutionary conservation of PRC2 targets. Results Here, we compare the H3K27me3 epigenomic profiles for the two closely related species Arabidopsis thaliana and Arabidopsis lyrata and the more distant species Arabis alpina, three Brassicaceae that diverged from each other within the past 24 million years. Using a robust set of gene orthologs present in the three species, we identify two classes of evolutionarily conserved PRC2 targets, which are characterized by either developmentally plastic or developmentally constrained H3K27me3 marking across species. Constrained H3K27me3 marking is associated with higher conservation of promoter sequence information content and higher nucleosome occupancy compared to plastic H3K27me3 marking. Moreover, gene orthologs with constrained H3K27me3 marking exhibit a higher degree of tissue specificity and tend to be involved in developmental functions, whereas gene orthologs with plastic H3K27me3 marking preferentially encode proteins associated with metabolism and stress responses. In addition, gene orthologs with constrained H3K27me3 marking are the predominant contributors to higher-order chromosome organization. Conclusions Our findings indicate that developmentally plastic and constrained H3K27me3 marking define two evolutionarily conserved modes of PRC2-mediated gene regulation that are associated with distinct selective pressures operating at multiple scales, from DNA sequence to gene function and chromosome architecture. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1333-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Claudia Chica
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, F-75005, France.,Present address: Institut Pasteur, Bioinformatics and Biostatistics Hub, C3BI, USR 3756 IP CNRS, Paris, France
| | - Alexandra Louis
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, F-75005, France
| | - Hugues Roest Crollius
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, F-75005, France
| | - Vincent Colot
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, F-75005, France.
| | - François Roudier
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, F-75005, France. .,Present address: Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342, Lyon, France.
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Abstract
The question of how noncoding RNAs are involved in Polycomb group (PcG) and Trithorax group (TrxG) regulation has been on an extraordinary journey over the last three decades. Favored models have risen and fallen, and healthy debates have swept back and forth. The field has recently reached a critical mass of compelling data that throws light on several previously unresolved issues. The time is ripe for a fruitful combination of these findings with two other long-running avenues of research, namely the biochemical properties of the PcG/TrxG system and the application of theoretical mathematical models toward an understanding of the system's regulatory properties. I propose that integrating our current knowledge of noncoding RNA into a quantitative biochemical and theoretical framework for PcG and TrxG regulation has the potential to reconcile several apparently conflicting models and identifies fascinating questions for future research.
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Affiliation(s)
- Leonie Ringrose
- Integrated Research Institute for Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
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49
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Schuettengruber B, Bourbon HM, Di Croce L, Cavalli G. Genome Regulation by Polycomb and Trithorax: 70 Years and Counting. Cell 2017; 171:34-57. [DOI: 10.1016/j.cell.2017.08.002] [Citation(s) in RCA: 611] [Impact Index Per Article: 87.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/17/2017] [Accepted: 08/01/2017] [Indexed: 01/05/2023]
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50
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An Evolutionary Conserved Epigenetic Mark of Polycomb Response Elements Implemented by Trx/MLL/COMPASS. Mol Cell 2017; 63:318-328. [PMID: 27447986 DOI: 10.1016/j.molcel.2016.06.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 04/07/2016] [Accepted: 06/10/2016] [Indexed: 12/20/2022]
Abstract
Polycomb response elements (PREs) are specific DNA sequences that stably maintain the developmental pattern of gene expression. Drosophila PREs are well characterized, whereas the existence of PREs in mammals remains debated. Accumulating evidence supports a model in which CpG islands recruit Polycomb group (PcG) complexes; however, which subset of CGIs is selected to serve as PREs is unclear. Trithorax (Trx) positively regulates gene expression in Drosophila and co-occupies PREs to antagonize Polycomb-dependent silencing. Here we demonstrate that Trx-dependent H3K4 dimethylation (H3K4me2) marks Drosophila PREs and maintains the developmental expression pattern of nearby genes. Similarly, the mammalian Trx homolog, MLL1, deposits H3K4me2 at CpG-dense regions that could serve as PREs. In the absence of MLL1 and H3K4me2, H3K27me3 levels, a mark of Polycomb repressive complex 2 (PRC2), increase at these loci. By inhibiting PRC2-dependent H3K27me3 in the absence of MLL1, we can rescue expression of these loci, demonstrating a functional balance between MLL1 and PRC2 activities at these sites. Thus, our study provides rules for identifying cell-type-specific functional mammalian PREs within the human genome.
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