1
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Uckelmann M, Davidovich C. Chromatin compaction by Polycomb group proteins revisited. Curr Opin Struct Biol 2024; 86:102806. [PMID: 38537534 DOI: 10.1016/j.sbi.2024.102806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 05/19/2024]
Abstract
The chromatin compaction activity of Polycomb group proteins has traditionally been considered essential for transcriptional repression. However, there is very little information on how Polycomb group proteins compact chromatin at the molecular level and no causal link between the compactness of chromatin and transcriptional repression. Recently, a more complete picture of Polycomb-dependent chromatin architecture has started to emerge, owing to advanced methods for imaging and chromosome conformation capture. Discoveries into Polycomb-driven phase separation add another layer of complexity. Recent observations generally imply that Polycomb group proteins modulate chromatin structure at multiple scales to reduce its dynamics and segregate it from active domains. Hence, it is reasonable to hypothesise that Polycomb group proteins maintain the energetically favourable state of compacted chromatin, rather than actively compact it.
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Affiliation(s)
- Michael Uckelmann
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3800, Australia.
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3800, Australia; EMBL-Australia, Clayton, Victoria, 3800, Australia.
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2
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Gurgo J, Walter JC, Fiche JB, Houbron C, Schaeffer M, Cavalli G, Bantignies F, Nollmann M. Multiplexed chromatin imaging reveals predominantly pairwise long-range coordination between Drosophila Polycomb genes. Cell Rep 2024; 43:114167. [PMID: 38691452 DOI: 10.1016/j.celrep.2024.114167] [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: 04/22/2022] [Revised: 02/15/2024] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
Polycomb (Pc) group proteins are transcriptional regulators with key roles in development, cell identity, and differentiation. Pc-bound chromatin regions form repressive domains that interact in 3D to assemble repressive nuclear compartments. Here, we use multiplexed chromatin imaging to investigate whether Pc compartments involve the clustering of multiple Pc domains during Drosophila development. Notably, 3D proximity between Pc targets is rare and involves predominantly pairwise interactions. These 3D proximities are particularly enhanced in segments where Pc genes are co-repressed. In addition, segment-specific expression of Hox Pc targets leads to their spatial segregation from Pc-repressed genes. Finally, non-Hox Pc targets are more proximal in regions where they are co-expressed. These results indicate that long-range Pc interactions are temporally and spatially regulated during differentiation and development but do not induce frequent clustering of multiple distant Pc genes.
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Affiliation(s)
- Julian Gurgo
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090 Montpellier, France
| | - Jean-Charles Walter
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, France
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090 Montpellier, France
| | - Christophe Houbron
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090 Montpellier, France
| | - Marie Schaeffer
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090 Montpellier, France
| | - Giacomo Cavalli
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396 Montpellier, France
| | - Frédéric Bantignies
- Institut de Génétique Humaine, CNRS UMR 9002, Université de Montpellier, 141 rue de la Cardonille, 34396 Montpellier, France.
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090 Montpellier, France.
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3
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Shi TH, Sugishita H, Gotoh Y. Crosstalk within and beyond the Polycomb repressive system. J Cell Biol 2024; 223:e202311021. [PMID: 38506728 PMCID: PMC10955045 DOI: 10.1083/jcb.202311021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024] Open
Abstract
The development of multicellular organisms depends on spatiotemporally controlled differentiation of numerous cell types and their maintenance. To generate such diversity based on the invariant genetic information stored in DNA, epigenetic mechanisms, which are heritable changes in gene function that do not involve alterations to the underlying DNA sequence, are required to establish and maintain unique gene expression programs. Polycomb repressive complexes represent a paradigm of epigenetic regulation of developmentally regulated genes, and the roles of these complexes as well as the epigenetic marks they deposit, namely H3K27me3 and H2AK119ub, have been extensively studied. However, an emerging theme from recent studies is that not only the autonomous functions of the Polycomb repressive system, but also crosstalks of Polycomb with other epigenetic modifications, are important for gene regulation. In this review, we summarize how these crosstalk mechanisms have improved our understanding of Polycomb biology and how such knowledge could help with the design of cancer treatments that target the dysregulated epigenome.
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Affiliation(s)
- Tianyi Hideyuki Shi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroki Sugishita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
| | - Yukiko Gotoh
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
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4
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Guan S, Tang J, Ma X, Miao R, Cheng B. CBX7C⋅PHC2 interaction facilitates PRC1 assembly and modulates its phase separation properties. iScience 2024; 27:109548. [PMID: 38600974 PMCID: PMC11004992 DOI: 10.1016/j.isci.2024.109548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 02/04/2024] [Accepted: 03/19/2024] [Indexed: 04/12/2024] Open
Abstract
CBX7 is a key component of PRC1 complex. Cbx7C is an uncharacterized Cbx7 splicing isoform specifically expressed in mouse embryonic stem cells (mESCs). We demonstrate that CBX7C functions as an epigenetic repressor at the classic PRC1 targets in mESCs, and its preferential interaction to PHC2 facilitates PRC1 assembly. Both Cbx7C and Phc2 are significantly upregulated during cell differentiation, and knockdown of Cbx7C abolishes the differentiation of mESCs to embryoid bodies. Interestingly, CBX7C⋅PHC2 interaction at low levels efficiently undergoes the formation of functional Polycomb bodies with high mobility, whereas the coordination of the two factors at high doses results in the formation of large, low-mobility, chromatin-free aggregates. Overall, these findings uncover the unique roles and molecular basis of the CBX7C⋅PHC2 interaction in PRC1 assembly on chromatin and Pc body formation and open a new avenue of controlling PRC1 activities via modulation of its phase separation properties.
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Affiliation(s)
- Shanli Guan
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Jiajia Tang
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Xiaojun Ma
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Ruidong Miao
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
| | - Bo Cheng
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, Lanzhou University, Lanzhou 730000, Gansu, P.R. China
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5
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Zhao J, Lan J, Wang M, Liu C, Fang Z, Song A, Zhang T, Wang L, Zhu B, Chen P, Yu J, Li G. H2AK119ub1 differentially fine-tunes gene expression by modulating canonical PRC1- and H1-dependent chromatin compaction. Mol Cell 2024; 84:1191-1205.e7. [PMID: 38458202 DOI: 10.1016/j.molcel.2024.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 11/15/2023] [Accepted: 02/16/2024] [Indexed: 03/10/2024]
Abstract
Polycomb repressive complex 1 (PRC1) is a key transcriptional regulator in development via modulating chromatin structure and catalyzing histone H2A ubiquitination at Lys119 (H2AK119ub1). H2AK119ub1 is one of the most abundant histone modifications in mammalian cells. However, the function of H2AK119ub1 in polycomb-mediated gene silencing remains debated. In this study, we reveal that H2AK119ub1 has two distinct roles in gene expression, through differentially modulating chromatin compaction mediated by canonical PRC1 and the linker histone H1. Interestingly, we find that H2AK119ub1 plays a positive role in transcription through interfering with the binding of canonical PRC1 to nucleosomes and therefore counteracting chromatin condensation. Conversely, we demonstrate that H2AK119ub1 facilitates H1-dependent chromatin condensation and enhances the silencing of developmental genes in mouse embryonic stem cells, suggesting that H1 may be one of several possible pathways for H2AK119ub1 in repressing transcription. These results provide insights and molecular mechanisms by which H2AK119ub1 differentially fine-tunes developmental gene expression.
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Affiliation(s)
- Jicheng Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Lan
- Department of Bioinformatics, School of Basic Medical Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Min Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Cuifang Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zheng Fang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Aoqun Song
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Tiantian Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Liang Wang
- Beijing Advanced Innovation Center for Structure Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100101, China
| | - Bing Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Chen
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Department of Immunology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China.
| | - Juan Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China; New Cornerstone Science Laboratory, Frontier Science Center for Immunology and Metabolism, Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China.
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6
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Franz P, Fierz B. Decoding Chromatin Ubiquitylation: A Chemical Biology Perspective. J Mol Biol 2024; 436:168442. [PMID: 38211893 DOI: 10.1016/j.jmb.2024.168442] [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: 11/09/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
Since Strahl and Allis proposed the "language of covalent histone modifications", a host of experimental studies have shed light on the different facets of chromatin regulation by epigenetic mechanisms. Initially proposed as a concept for controlling gene transcription, the regulation of deposition and removal of histone post-translational modifications (PTMs), such as acetylation, methylation, and phosphorylation, have been implicated in many chromatin regulation pathways. However, large PTMs such as ubiquitylation challenge research on many levels due to their chemical complexity. In recent years, chemical tools have been developed to generate chromatin in defined ubiquitylation states in vitro. Chemical biology approaches are now used to link specific histone ubiquitylation marks with downstream chromatin regulation events on the molecular level. Here, we want to highlight how chemical biology approaches have empowered the mechanistic study of chromatin ubiquitylation in the context of gene regulation and DNA repair with attention to future challenges.
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Affiliation(s)
- Pauline Franz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Beat Fierz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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7
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Ryan CW, Peirent ER, Regan SL, Guxholli A, Bielas SL. H2A monoubiquitination: insights from human genetics and animal models. Hum Genet 2024; 143:511-527. [PMID: 37086328 DOI: 10.1007/s00439-023-02557-x] [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: 02/22/2023] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
Metazoan development arises from spatiotemporal control of gene expression, which depends on epigenetic regulators like the polycomb group proteins (PcG) that govern the chromatin landscape. PcG proteins facilitate the addition and removal of histone 2A monoubiquitination at lysine 119 (H2AK119ub1), which regulates gene expression, cell fate decisions, cell cycle progression, and DNA damage repair. Regulation of these processes by PcG proteins is necessary for proper development, as pathogenic variants in these genes are increasingly recognized to underly developmental disorders. Overlapping features of developmental syndromes associated with pathogenic variants in specific PcG genes suggest disruption of central developmental mechanisms; however, unique clinical features observed in each syndrome suggest additional non-redundant functions for each PcG gene. In this review, we describe the clinical manifestations of pathogenic PcG gene variants, review what is known about the molecular functions of these gene products during development, and interpret the clinical data to summarize the current evidence toward an understanding of the genetic and molecular mechanism.
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Affiliation(s)
- Charles W Ryan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
- Medical Science Training Program, University of Michigan Medical School, 3703 Med Sci II, 1241 E. Catherine St., Ann Arbor, MI, 48109-5618, USA
| | - Emily R Peirent
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Samantha L Regan
- Department of Human Genetics, University of Michigan Medical School, 3703 Med Sci II, 1241 E. Catherine St., Ann Arbor, MI, 48109-5618, USA
| | - Alba Guxholli
- Department of Human Genetics, University of Michigan Medical School, 3703 Med Sci II, 1241 E. Catherine St., Ann Arbor, MI, 48109-5618, USA
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, 48199-5618, USA
| | - Stephanie L Bielas
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA.
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA.
- Department of Human Genetics, University of Michigan Medical School, 3703 Med Sci II, 1241 E. Catherine St., Ann Arbor, MI, 48109-5618, USA.
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, 48199-5618, USA.
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8
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Bajpai SK, Nisha, Pandita S, Bahadur A, Verma PC. Recent advancements in the role of histone acetylation dynamics to improve stress responses in plants. Mol Biol Rep 2024; 51:413. [PMID: 38472555 DOI: 10.1007/s11033-024-09300-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 01/30/2024] [Indexed: 03/14/2024]
Abstract
In eukaryotes, transcriptional regulation is determined by the DNA sequence and is facilitated through sophisticated and complex chromatin alterations and histone remodelling. Recent research has shown that the histone acetylation dynamic, an intermittent and reversible substitution, constitutes a prerequisite for chromatin modification. These changes in chromatin structure modulate genome-wide and specific changes in response to external and internal cues like cell differentiation, development, growth, light temperature, and biotic stresses. Histone acetylation dynamics also control the cell cycle. HATs and HDACs play a critical role in gene expression modulation during plant growth and response to environmental circumstances. It has been well established that HATs and HDACs interact with various distinct transcription factors and chromatin-remodelling proteins (CRPs) involved in the transcriptional regulation of several developmental processes. This review explores recent research on histone acyltransferases and histone deacetylases, mainly focusing on their involvement in plant biotic stress responses. Moreover, we also emphasized the research gaps that must be filled to fully understand the complete function of histone acetylation dynamics during biotic stress responses in plants. A thorough understanding of histone acetylation will make it possible to enhance tolerance against various kinds of stress and decrease yield losses in many crops.
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Affiliation(s)
- Sanjay Kumar Bajpai
- Molecular Biology & Biotechnology Division, CSIR-National Botanical Research Institute, (Council of Scientific and Industrial Research) Rana Pratap Marg, Lucknow, UP, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Nisha
- Molecular Biology & Biotechnology Division, CSIR-National Botanical Research Institute, (Council of Scientific and Industrial Research) Rana Pratap Marg, Lucknow, UP, 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Shivali Pandita
- Molecular Biology & Biotechnology Division, CSIR-National Botanical Research Institute, (Council of Scientific and Industrial Research) Rana Pratap Marg, Lucknow, UP, 226001, India
- Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Anand Bahadur
- Molecular Biology & Biotechnology Division, CSIR-National Botanical Research Institute, (Council of Scientific and Industrial Research) Rana Pratap Marg, Lucknow, UP, 226001, India
- Department of Botany, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Praveen C Verma
- Molecular Biology & Biotechnology Division, CSIR-National Botanical Research Institute, (Council of Scientific and Industrial Research) Rana Pratap Marg, Lucknow, UP, 226001, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India.
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9
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Murphy SE, Boettiger AN. Polycomb repression of Hox genes involves spatial feedback but not domain compaction or phase transition. Nat Genet 2024; 56:493-504. [PMID: 38361032 DOI: 10.1038/s41588-024-01661-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024]
Abstract
Polycomb group proteins have a critical role in silencing transcription during development. It is commonly proposed that Polycomb-dependent changes in genome folding, which compact chromatin, contribute directly to repression by blocking the binding of activating complexes. Recently, it has also been argued that liquid-liquid demixing of Polycomb proteins facilitates this compaction and repression by phase-separating target genes into a membraneless compartment. To test these models, we used Optical Reconstruction of Chromatin Architecture to trace the Hoxa gene cluster, a canonical Polycomb target, in thousands of single cells. Across multiple cell types, we find that Polycomb-bound chromatin frequently explores decompact states and partial mixing with neighboring chromatin, while remaining uniformly repressed, challenging the repression-by-compaction or phase-separation models. Using polymer simulations, we show that these observed flexible ensembles can be explained by 'spatial feedback'-transient contacts that contribute to the propagation of the epigenetic state (epigenetic memory), without inducing a globular organization.
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Affiliation(s)
- Sedona Eve Murphy
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
- Department of Cell Biology, Yale University, New Haven, CT, USA
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10
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Ito S, Umehara T, Koseki H. Polycomb-mediated histone modifications and gene regulation. Biochem Soc Trans 2024; 52:151-161. [PMID: 38288743 DOI: 10.1042/bst20230336] [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: 11/14/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 02/29/2024]
Abstract
Polycomb repressive complexes 1 and 2 (PRC1 and PRC2) are transcriptional repressor complexes that play a fundamental role in epigenomic regulation and the cell-fate decision; these complexes are widely conserved in multicellular organisms. PRC1 is an E3 ubiquitin (ub) ligase that generates histone H2A ubiquitinated at lysine (K) 119 (H2AK119ub1), whereas PRC2 is a histone methyltransferase that specifically catalyzes tri-methylation of histone H3K27 (H3K27me3). Genome-wide analyses have confirmed that these two key epigenetic marks highly overlap across the genome and contribute to gene repression. We are now beginning to understand the molecular mechanisms that enable PRC1 and PRC2 to identify their target sites in the genome and communicate through feedback mechanisms to create Polycomb chromatin domains. Recently, it has become apparent that PRC1-induced H2AK119ub1 not only serves as a docking site for PRC2 but also affects the dynamics of the H3 tail, both of which enhance PRC2 activity, suggesting that trans-tail communication between H2A and H3 facilitates the formation of the Polycomb chromatin domain. In this review, we discuss the emerging principles that define how PRC1 and PRC2 establish the Polycomb chromatin domain and regulate gene expression in mammals.
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Affiliation(s)
- Shinsuke Ito
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takashi Umehara
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Laboratory for Epigenetics Drug Discovery, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Haruhiko Koseki
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
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11
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Uckelmann M, Levina V, Taveneau C, Han Ng X, Pandey V, Martinez J, Mendiratta S, Houx J, Boudes M, Venugopal H, Trépout S, Zhang Q, Flanigan S, Li M, Sierecki E, Gambin Y, Das PP, Bell O, de Marco A, Davidovich C. Dynamic PRC1-CBX8 stabilizes a porous structure of chromatin condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.08.539931. [PMID: 38405976 PMCID: PMC10888862 DOI: 10.1101/2023.05.08.539931] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The compaction of chromatin is a prevalent paradigm in gene repression. Chromatin compaction is commonly thought to repress transcription by restricting chromatin accessibility. However, the spatial organisation and dynamics of chromatin compacted by gene-repressing factors are unknown. Using cryo-electron tomography, we solved the threedimensional structure of chromatin condensed by the Polycomb Repressive Complex 1 (PRC1) in a complex with CBX8. PRC1-condensed chromatin is porous and stabilised through multivalent dynamic interactions of PRC1 with chromatin. Mechanistically, positively charged residues on the internally disordered regions (IDRs) of CBX8 mask negative charges on the DNA to stabilize the condensed state of chromatin. Within condensates, PRC1 remains dynamic while maintaining a static chromatin structure. In differentiated mouse embryonic stem cells, CBX8-bound chromatin remains accessible. These findings challenge the idea of rigidly compacted polycomb domains and instead provides a mechanistic framework for dynamic and accessible PRC1-chromatin condensates.
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Affiliation(s)
- Michael Uckelmann
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Vita Levina
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Cyntia Taveneau
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Monash University; Clayton, Victoria, 3800, Australia
| | - Xiao Han Ng
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Varun Pandey
- Department of Anatomy and Developmental Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University; Clayton, Victoria, 3800, Australia
| | - Jasmine Martinez
- Departments of Biochemistry and Molecular Medicine, and Stem Cell and Regenerative Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Shweta Mendiratta
- Departments of Biochemistry and Molecular Medicine, and Stem Cell and Regenerative Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Justin Houx
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW, 2052 Australia
| | - Marion Boudes
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Monash, Victoria, Australia
| | - Sylvain Trépout
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Monash, Victoria, Australia
| | - Qi Zhang
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Sarena Flanigan
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
| | - Minrui Li
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
- Faculty of Information Technology, Monash University; Clayton, Victoria, 3800, Australia
| | - Emma Sierecki
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW, 2052 Australia
| | - Yann Gambin
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW, 2052 Australia
| | - Partha Pratim Das
- Department of Anatomy and Developmental Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University; Clayton, Victoria, 3800, Australia
| | - Oliver Bell
- Departments of Biochemistry and Molecular Medicine, and Stem Cell and Regenerative Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Alex de Marco
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Monash University; Clayton, Victoria, 3800, Australia
- Simons Electron Microscopy Center, New York Structural Biology Center, New York 10027 NY, United States of America
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University; Clayton, Victoria, 3800, Australia
- EMBL-Australia; Clayton, Victoria, 3800, Australia
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12
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McGrath KE, Koniski AD, Murphy K, Getman M, An HH, Schulz VP, Kim AR, Zhang B, Schofield TL, Papoin J, Blanc L, Kingsley PD, Westhoff CM, Gallagher PG, Chou ST, Steiner LA, Palis J. BMI1 regulates human erythroid self-renewal through both gene repression and gene activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578704. [PMID: 38370741 PMCID: PMC10871261 DOI: 10.1101/2024.02.02.578704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
The limited proliferative capacity of erythroid precursors is a major obstacle to generate sufficient numbers of in vitro-derived red blood cells (RBC) for clinical purposes. We and others have determined that BMI1, a member of the polycomb repressive complex 1 (PRC1), is both necessary and sufficient to drive extensive proliferation of self-renewing erythroblasts (SREs). However, the mechanisms of BMI1 action remain poorly understood. BMI1 overexpression led to 10 billion-fold increase BMI1-induced (i)SRE self-renewal. Despite prolonged culture and BMI1 overexpression, human iSREs can terminally mature and agglutinate with typing reagent monoclonal antibodies against conventional RBC antigens. BMI1 and RING1B occupancy, along with repressive histone marks, were identified at known BMI1 target genes, including the INK-ARF locus, consistent with an altered cell cycle following BMI1 inhibition. We also identified upregulated BMI1 target genes with low repressive histone modifications, including key regulator of cholesterol homeostasis. Functional studies suggest that both cholesterol import and synthesis are essential for BMI1-associated self-renewal. These findings support the hypothesis that BMI1 regulates erythroid self-renewal not only through gene repression but also through gene activation and offer a strategy to expand the pool of immature erythroid precursors for eventual clinical uses.
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Affiliation(s)
- Kathleen E. McGrath
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Anne D. Koniski
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Kristin Murphy
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Michael Getman
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Hyun Hyung An
- Dept. of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Ah Ram Kim
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Bin Zhang
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Taylor L. Schofield
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Julien Papoin
- Institute of Molecular Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Lionel Blanc
- Institute of Molecular Medicine, Feinstein Institutes for Medical Research, Manhasset, NY, USA
| | - Paul D. Kingsley
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | | | - Patrick G. Gallagher
- Dept. of Pediatrics, Yale School of Medicine, New Haven, CT, USA
- Nationwide Children’s Hospital, Ohio State University, Columbus, OH, USA
| | - Stella T. Chou
- Dept. of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Laurie A. Steiner
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - James Palis
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
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13
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Shen X, Chen C, Wang Y, Zheng W, Zheng J, Jones AE, Zhu B, Zhang H, Lyons C, Rijal A, Moley JA, Cao G, Liu K, Winn R, Dickinson A, Zhang K, Wang H. Role of histone variants H2BC1 and H2AZ.2 in H2AK119ub nucleosome organization and Polycomb gene silencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575234. [PMID: 38293106 PMCID: PMC10827191 DOI: 10.1101/2024.01.16.575234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Ubiquitination of histone H2A at lysine 119 residue (H2AK119ub) plays critical roles in a wide range of physiological processes, including Polycomb gene silencing 1,2 , replication 3-5 , DNA damage repair 6-10 , X inactivation 11,12 , and heterochromatin organization 13,14 . However, the underlying mechanism and structural basis of H2AK119ub remains largely elusive. In this study, we report that H2AK119ub nucleosomes have a unique composition, containing histone variants H2BC1 and H2AZ.2, and importantly, this composition is required for H2AK119ub and Polycomb gene silencing. Using the UAB domain of RSF1, we purified H2AK119ub nucleosomes to a sufficient amount and purity. Mass spectrometry analyses revealed that H2AK119ub nucleosomes contain the histone variants H2BC1 and H2AZ.2. A cryo-EM study resolved the structure of native H2AK119ub nucleosomes to a 2.6A resolution, confirming H2BC1 in one subgroup of H2AK119ub nucleosomes. Tandem GST-UAB pulldown, Flag-H2AZ.2, and HA-H2BC1 immunoprecipitation revealed that H2AK119ub nucleosomes could be separated into distinct subgroups, suggesting their composition heterogeneity and potential dynamic organization. Knockout or knockdown of H2BC1 or H2AZ.2 reduced cellular H2AK119ub levels, establishing H2BC1 and H2AZ.2 as critical determinants of H2AK119ub. Furthermore, genomic binding profiles of H2BC1 and H2AZ.2 overlapped significantly with H2AK119ub binding, with the most significant overlapping in the gene body and intergenic regions. Finally, assays in developing embryos reveal an interaction of H2AZ.2, H2BC1, and RING1A in vivo . Thus, this study revealed, for the first time, that the H2AK119ub nucleosome has a unique composition, and this composition is required for H2AK119ub and Polycomb gene silencing.
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14
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Seif E, Francis NJ. A Two-Step Mechanism for Creating Stable, Condensed Chromatin with the Polycomb Complex PRC1. Molecules 2024; 29:323. [PMID: 38257239 PMCID: PMC10821450 DOI: 10.3390/molecules29020323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
The Drosophila PRC1 complex regulates gene expression by modifying histone proteins and chromatin architecture. Two PRC1 subunits, PSC and Ph, are most implicated in chromatin architecture. In vitro, PRC1 compacts chromatin and inhibits transcription and nucleosome remodeling. The long disordered C-terminal region of PSC (PSC-CTR) is important for these activities, while Ph has little effect. In cells, Ph is important for condensate formation, long-range chromatin interactions, and gene regulation, and its polymerizing sterile alpha motif (SAM) is implicated in these activities. In vitro, truncated Ph containing the SAM and two other conserved domains (mini-Ph) undergoes phase separation with chromatin, suggesting a mechanism for SAM-dependent condensate formation in vivo. How the distinct activities of PSC and Ph on chromatin function together in PRC1 is not known. To address this question, we analyzed structures formed with large chromatin templates and PRC1 in vitro. PRC1 bridges chromatin into extensive fibrillar networks. Ph, its SAM, and SAM polymerization activity have little effect on these structures. Instead, the PSC-CTR controls their growth, and is sufficient for their formation. To understand how phase separation driven by Ph SAM intersects with the chromatin bridging activity of the PSC-CTR, we used mini-Ph to form condensates with chromatin and then challenged them with PRC1 lacking Ph (PRC1ΔPh). PRC1ΔPh converts mini-Ph chromatin condensates into clusters of small non-fusing condensates and bridged fibers. These condensates retain a high level of chromatin compaction and do not intermix. Thus, phase separation of chromatin by mini-Ph, followed by the action of the PSC-CTR, creates a unique chromatin organization with regions of high nucleosome density and extraordinary stability. We discuss how this coordinated sequential activity of two proteins found in the same complex may occur and the possible implications of stable chromatin architectures in maintaining transcription states.
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Affiliation(s)
- Elias Seif
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
| | - Nicole J. Francis
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montréal, QC H4A 3J1, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada
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15
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Liu J, Fan H, Liang X, Chen Y. Polycomb repressor complex: Its function in human cancer and therapeutic target strategy. Biomed Pharmacother 2023; 169:115897. [PMID: 37981459 DOI: 10.1016/j.biopha.2023.115897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
The Polycomb Repressor Complex (PRC) plays a pivotal role in gene regulation during development and disease, with dysregulation contributing significantly to various human cancers. The intricate interplay between PRC and cellular signaling pathways sheds light on cancer complexity. PRC presents promising therapeutic opportunities, with inhibitors undergoing rigorous evaluation in preclinical and clinical studies. In this review, we emphasize the critical role of PRC complex in gene regulation, particularly PcG proteins mediated chromatin compaction through phase separation. We also highlight the pathological implications of PRC complex dysregulation in various tumors, elucidating underlying mechanisms driving cancer progression. The burgeoning field of therapeutic strategies targeting PRC complexes, notably EZH2 inhibitors, has advanced significantly. However, we explore the need for combination therapies to enhance PRC targeted treatments efficacy, providing a glimpse into the future of cancer therapeutics.
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Affiliation(s)
- Jingrong Liu
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Hongjie Fan
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Xinmiao Liang
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yang Chen
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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16
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Kim SJ, Kiser PK, Asfaha S, DeKoter RP, Dick FA. EZH2 inhibition stimulates repetitive element expression and viral mimicry in resting splenic B cells. EMBO J 2023; 42:e114462. [PMID: 37934086 PMCID: PMC10711652 DOI: 10.15252/embj.2023114462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023] Open
Abstract
Mammalian cells repress expression of repetitive genomic sequences by forming heterochromatin. However, the consequences of ectopic repeat expression remain unclear. Here we demonstrate that inhibitors of EZH2, the catalytic subunit of the Polycomb repressive complex 2 (PRC2), stimulate repeat misexpression and cell death in resting splenic B cells. B cells are uniquely sensitive to these agents because they exhibit high levels of histone H3 lysine 27 trimethylation (H3K27me3) and correspondingly low DNA methylation at repeat elements. We generated a pattern recognition receptor loss-of-function mouse model, called RIC, with mutations in Rigi (encoding for RIG-I), Ifih1 (MDA5), and Cgas. In both wildtype and RIC mutant B cells, EZH2 inhibition caused loss of H3K27me3 at repetitive elements and upregulated their expression. However, NF-κB-dependent expression of inflammatory chemokines and subsequent cell death was suppressed by the RIC mutations. We further show that inhibition of EZH2 in cancer cells requires the same pattern recognition receptors to activate an interferon response. Together, the results reveal chemokine expression induced by EZH2 inhibitors in B cells as a novel inflammatory response to genomic repeat expression. Given the overlap of genes induced by EZH2 inhibitors and Epstein-Barr virus infection, this response can be described as a form of viral mimicry.
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Affiliation(s)
- Seung J Kim
- London Regional Cancer ProgramChildren's Health Research InstituteLondonONCanada
- London Health Sciences Research InstituteLondonONCanada
- Department of BiochemistryWestern UniversityLondonONCanada
| | - Patti K Kiser
- Department of Pathology and Laboratory MedicineWestern UniversityLondonONCanada
| | - Samuel Asfaha
- London Regional Cancer ProgramChildren's Health Research InstituteLondonONCanada
- London Health Sciences Research InstituteLondonONCanada
- Department of Pathology and Laboratory MedicineWestern UniversityLondonONCanada
- Department of MedicineWestern UniversityLondonONCanada
| | - Rodney P DeKoter
- Department of Microbiology & ImmunologyWestern UniversityLondonONCanada
| | - Frederick A Dick
- London Regional Cancer ProgramChildren's Health Research InstituteLondonONCanada
- London Health Sciences Research InstituteLondonONCanada
- Department of Pathology and Laboratory MedicineWestern UniversityLondonONCanada
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17
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Lu G, Li P. PHF1 compartmentalizes PRC2 via phase separation. Biochem J 2023; 480:1833-1844. [PMID: 37888776 DOI: 10.1042/bcj20230040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 10/28/2023]
Abstract
Polycomb repressive complex 2 (PRC2) is central to polycomb repression as it trimethylates lysine 27 on histone H3 (H3K27me3). How PRC2 is recruited to its targets to deposit H3K27me3 remains an open question. Polycomb-like (PCL) proteins, a group of conserved PRC2 accessory proteins, can direct PRC2 to its targets. In this report, we demonstrate that a PCL protein named PHF1 forms phase-separated condensates at H3K27me3 loci that recruit PRC2. Combining cellular observation and biochemical reconstitution, we show that the N-terminal domains of PHF1 cooperatively mediate target recognition, the chromo-like domain recruits PRC2, and the intrinsically disordered region (IDR) drives phase separation. Moreover, we reveal that the condensates compartmentalize PRC2, DNA, and nucleosome arrays by phase separation. Luciferase reporter assays confirm that PHF1 phase separation promotes transcription repression, further supporting a role of the condensates in polycomb repression. Based on our findings, we propose that these condensates create favorable microenvironments at the target loci for PRC2 to function.
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Affiliation(s)
- Genzhe Lu
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Beijing 100084, China
- Tsinghua Xuetang Life Science Program, Tsinghua University, Beijing 100084, China
| | - Pilong Li
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Beijing 100084, China
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18
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Liu Y, Hu G, Yang S, Yao M, Liu Z, Yan C, Wen Y, Ping W, Wang J, Song Y, Dong X, Pan G, Yao H. Functional dissection of PRC1 subunits RYBP and YAF2 during neural differentiation of embryonic stem cells. Nat Commun 2023; 14:7164. [PMID: 37935677 PMCID: PMC10630410 DOI: 10.1038/s41467-023-42507-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/12/2023] [Indexed: 11/09/2023] Open
Abstract
Polycomb repressive complex 1 (PRC1) comprises two different complexes: CBX-containing canonical PRC1 (cPRC1) and RYBP/YAF2-containing variant PRC1 (vPRC1). RYBP-vPRC1 or YAF2-vPRC1 catalyzes H2AK119ub through a positive-feedback model; however, whether RYBP and YAF2 have different regulatory functions is still unclear. Here, we show that the expression of RYBP and YAF2 decreases and increases, respectively, during neural differentiation of embryonic stem cells (ESCs). Rybp knockout impairs neural differentiation by activating Wnt signaling and derepressing nonneuroectoderm-associated genes. However, Yaf2 knockout promotes neural differentiation and leads to redistribution of RYBP binding, increases enrichment of RYBP and H2AK119ub on the RYBP-YAF2 cotargeted genes, and prevents ectopic derepression of nonneuroectoderm-associated genes in neural-differentiated cells. Taken together, this study reveals that RYBP and YAF2 function differentially in regulating mESC neural differentiation.
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Affiliation(s)
- Yanjiang Liu
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Gongcheng Hu
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China
| | - Shengxiong Yang
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China
| | - Mingze Yao
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Zicong Liu
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Chenghong Yan
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Yulin Wen
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wangfang Ping
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Juehan Wang
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yawei Song
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Xiaotao Dong
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
| | - Guangjin Pan
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hongjie Yao
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, China.
- Department of Basic Research, Guangzhou National Laboratory, Guangzhou, China.
- University of Chinese Academy of Sciences, Beijing, China.
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19
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Hamali B, Amine AAA, Al-Sady B. Regulation of the heterochromatin spreading reaction by trans-acting factors. Open Biol 2023; 13:230271. [PMID: 37935357 PMCID: PMC10645111 DOI: 10.1098/rsob.230271] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/03/2023] [Indexed: 11/09/2023] Open
Abstract
Heterochromatin is a gene-repressive protein-nucleic acid ultrastructure that is initially nucleated by DNA sequences. However, following nucleation, heterochromatin can then propagate along the chromatin template in a sequence-independent manner in a reaction termed spreading. At the heart of this process are enzymes that deposit chemical information on chromatin, which attracts the factors that execute chromatin compaction and transcriptional or co/post-transcriptional gene silencing. Given that these enzymes deposit guiding chemical information on chromatin they are commonly termed 'writers'. While the processes of nucleation and central actions of writers have been extensively studied and reviewed, less is understood about how the spreading process is regulated. We discuss how the chromatin substrate is prepared for heterochromatic spreading, and how trans-acting factors beyond writer enzymes regulate it. We examine mechanisms by which trans-acting factors in Suv39, PRC2, SETDB1 and SIR writer systems regulate spreading of the respective heterochromatic marks across chromatin. While these systems are in some cases evolutionarily and mechanistically quite distant, common mechanisms emerge which these trans-acting factors exploit to tune the spreading reaction.
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Affiliation(s)
- Bulut Hamali
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Ahmed A A Amine
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
| | - Bassem Al-Sady
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
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20
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Shevelyov YY. Interactions of Chromatin with the Nuclear Lamina and Nuclear Pore Complexes. Int J Mol Sci 2023; 24:15771. [PMID: 37958755 PMCID: PMC10649103 DOI: 10.3390/ijms242115771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
Heterochromatin and euchromatin form different spatial compartments in the interphase nucleus, with heterochromatin being localized mainly at the nuclear periphery. The mechanisms responsible for peripheral localization of heterochromatin are still not fully understood. The nuclear lamina and nuclear pore complexes were obvious candidates for the role of heterochromatin binders. This review is focused on recent studies showing that heterochromatin interactions with the nuclear lamina and nuclear pore complexes maintain its peripheral localization. Differences in chromatin interactions with the nuclear envelope in cell populations and in individual cells are also discussed.
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Affiliation(s)
- Yuri Y Shevelyov
- Laboratory of Analysis of Gene Regulation, National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
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21
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Allegra A, Caserta S, Mirabile G, Gangemi S. Aging and Age-Related Epigenetic Drift in the Pathogenesis of Leukemia and Lymphomas: New Therapeutic Targets. Cells 2023; 12:2392. [PMID: 37830606 PMCID: PMC10572300 DOI: 10.3390/cells12192392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/24/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
One of the traits of cancer cells is abnormal DNA methylation patterns. The idea that age-related epigenetic changes may partially explain the increased risk of cancer in the elderly is based on the observation that aging is also accompanied by comparable changes in epigenetic patterns. Lineage bias and decreased stem cell function are signs of hematopoietic stem cell compartment aging. Additionally, aging in the hematopoietic system and the stem cell niche have a role in hematopoietic stem cell phenotypes linked with age, such as leukemia and lymphoma. Understanding these changes will open up promising pathways for therapies against age-related disorders because epigenetic mechanisms are reversible. Additionally, the development of high-throughput epigenome mapping technologies will make it possible to identify the "epigenomic identity card" of every hematological disease as well as every patient, opening up the possibility of finding novel molecular biomarkers that can be used for diagnosis, prediction, and prognosis.
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Affiliation(s)
- Alessandro Allegra
- Division of Hematology, Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, University of Messina, Via Consolare Valeria, 98125 Messina, Italy; (S.C.); (G.M.)
| | - Santino Caserta
- Division of Hematology, Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, University of Messina, Via Consolare Valeria, 98125 Messina, Italy; (S.C.); (G.M.)
| | - Giuseppe Mirabile
- Division of Hematology, Department of Human Pathology in Adulthood and Childhood “Gaetano Barresi”, University of Messina, Via Consolare Valeria, 98125 Messina, Italy; (S.C.); (G.M.)
| | - Sebastiano Gangemi
- Allergy and Clinical Immunology Unit, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 98125 Messina, Italy;
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22
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Teano G, Concia L, Wolff L, Carron L, Biocanin I, Adamusová K, Fojtová M, Bourge M, Kramdi A, Colot V, Grossniklaus U, Bowler C, Baroux C, Carbone A, Probst AV, Schrumpfová PP, Fajkus J, Amiard S, Grob S, Bourbousse C, Barneche F. Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis. Cell Rep 2023; 42:112894. [PMID: 37515769 DOI: 10.1016/j.celrep.2023.112894] [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: 01/21/2021] [Revised: 12/02/2022] [Accepted: 07/13/2023] [Indexed: 07/31/2023] Open
Abstract
While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment. This study provides a mechanistic framework by which H1 avoids the formation of gigantic H3K27me3-rich domains at telomeric sequences and contributes to safeguard nucleus architecture.
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Affiliation(s)
- Gianluca Teano
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France; Université Paris-Saclay, 91190 Orsay, France
| | - Lorenzo Concia
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Léa Wolff
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Léopold Carron
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
| | - Ivona Biocanin
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France; Université Paris-Saclay, 91190 Orsay, France
| | - Kateřina Adamusová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Michael Bourge
- Cytometry Facility, Imagerie-Gif, Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Amira Kramdi
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Vincent Colot
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Chris Bowler
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Célia Baroux
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Alessandra Carbone
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
| | - Aline V Probst
- CNRS UMR6293, Université Clermont Auvergne, INSERM U1103, GReD, CRBC, Clermont-Ferrand, France
| | - Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Simon Amiard
- CNRS UMR6293, Université Clermont Auvergne, INSERM U1103, GReD, CRBC, Clermont-Ferrand, France
| | - Stefan Grob
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Clara Bourbousse
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Fredy Barneche
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France.
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23
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Erokhin M, Mogila V, Lomaev D, Chetverina D. Polycomb Recruiters Inside and Outside of the Repressed Domains. Int J Mol Sci 2023; 24:11394. [PMID: 37511153 PMCID: PMC10379775 DOI: 10.3390/ijms241411394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/24/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
The establishment and stable inheritance of individual patterns of gene expression in different cell types are required for the development of multicellular organisms. The important epigenetic regulators are the Polycomb group (PcG) and Trithorax group (TrxG) proteins, which control the silenced and active states of genes, respectively. In Drosophila, the PcG/TrxG group proteins are recruited to the DNA regulatory sequences termed the Polycomb response elements (PREs). The PREs are composed of the binding sites for different DNA-binding proteins, the so-called PcG recruiters. Currently, the role of the PcG recruiters in the targeting of the PcG proteins to PREs is well documented. However, there are examples where the PcG recruiters are also implicated in the active transcription and in the TrxG function. In addition, there is increasing evidence that the genome-wide PcG recruiters interact with the chromatin outside of the PREs and overlap with the proteins of differing regulatory classes. Recent studies of the interactomes of the PcG recruiters significantly expanded our understanding that they have numerous interactors besides the PcG proteins and that their functions extend beyond the regulation of the PRE repressive activity. Here, we summarize current data about the functions of the PcG recruiters.
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Affiliation(s)
- Maksim Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Vladic Mogila
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Dmitry Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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24
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Kim JJ, Steinson ER, Lau MS, de Rooij DG, Page DC, Kingston RE. Cell type-specific role of CBX2 and its disordered region in spermatogenesis. Genes Dev 2023; 37:640-660. [PMID: 37553262 PMCID: PMC10499018 DOI: 10.1101/gad.350393.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 07/28/2023] [Indexed: 08/10/2023]
Abstract
Polycomb group (PcG) proteins maintain the repressed state of lineage-inappropriate genes and are therefore essential for embryonic development and adult tissue homeostasis. One critical function of PcG complexes is modulating chromatin structure. Canonical Polycomb repressive complex 1 (cPRC1), particularly its component CBX2, can compact chromatin and phase-separate in vitro. These activities are hypothesized to be critical for forming a repressed physical environment in cells. While much has been learned by studying these PcG activities in cell culture models, it is largely unexplored how cPRC1 regulates adult stem cells and their subsequent differentiation in living animals. Here, we show in vivo evidence of a critical nonenzymatic repressive function of cPRC1 component CBX2 in the male germline. CBX2 is up-regulated as spermatogonial stem cells differentiate and is required to repress genes that were active in stem cells. CBX2 forms condensates (similar to previously described Polycomb bodies) that colocalize with target genes bound by CBX2 in differentiating spermatogonia. Single-cell analyses of mosaic Cbx2 mutant testes show that CBX2 is specifically required to produce differentiating A1 spermatogonia. Furthermore, the region of CBX2 responsible for compaction and phase separation is needed for the long-term maintenance of male germ cells in the animal. These results emphasize that the regulation of chromatin structure by CBX2 at a specific stage of spermatogenesis is critical, which distinguishes this from a mechanism that is reliant on histone modification.
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Affiliation(s)
- Jongmin J Kim
- Department of Molecular Biology, MGH Research Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Emma R Steinson
- Department of Molecular Biology, MGH Research Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Mei Sheng Lau
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology, and Research (A*STAR), Proteos, Singapore 138673, Republic of Singapore
| | - Dirk G de Rooij
- Reproductive Biology Group, Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, the Netherlands
| | - David C Page
- Whitehead Institute, Cambridge, Massachusetts 02142, USA
- Howard Hughes Medical Institute, Whitehead Institute, Cambridge, Massachusetts 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert E Kingston
- Department of Molecular Biology, MGH Research Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA;
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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25
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Sahu A, Singh R, Verma PK. Plant BBR/BPC transcription factors: unlocking multilayered regulation in development, stress and immunity. PLANTA 2023; 258:31. [PMID: 37368167 DOI: 10.1007/s00425-023-04188-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/17/2023] [Indexed: 06/28/2023]
Abstract
MAIN CONCLUSION This review provides a detailed structural and functional understanding of BBR/BPC TF, their conservation across the plant lineage, and their comparative study with animal GAFs. Plant-specific Barley B Recombinant/Basic PentaCysteine (BBR/BPC) transcription factor (TF) family binds to "GA" repeats similar to animal GAGA Factors (GAFs). These GAGA binding proteins are among the few TFs that regulate the genes at multiple steps by modulating the chromatin structure. The hallmark of the BBR/BPC TF family is the presence of a conserved C-terminal region with five cysteine residues. In this review, we present: first, the structural distinct yet functional similar relation of plant BBR/BPC TF with animal GAFs, second, the conservation of BBR/BPC across the plant lineage, third, their role in planta, fourth, their potential interacting partners and structural insights. We conclude that BBR/BPC TFs have multifaceted roles in plants. Besides the earliest identified function in homeotic gene regulation and developmental processes, presently BBR/BPC TFs were identified in hormone signaling, stress, circadian oscillation, and sex determination processes. Understanding how plants' development and stress processes are coordinated is central to divulging the growth-immunity trade-off regulation. The BBR/BPC TFs may hold keys to divulge the interactions between development and immunity. Moreover, the conservation of BBR/BPC across plant lineage makes it an evolutionary vital gene family. Consequently, BBR/BPCs are prospective to attract the increasing attention of the scientific communities as they are probably at the crossroads of diverse fundamental processes.
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Affiliation(s)
- Anubhav Sahu
- Plant Immunity Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Ritu Singh
- Plant Immunity Laboratory, National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Praveen Kumar Verma
- Plant Immunity Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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26
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Halder S, Paul M, Dyagala S, Aggrawal R, Aswal VK, Biswas S, Saha SK. Role of Gemini Surfactants with Variable Spacers and SiO 2 Nanoparticles in ct-DNA Compaction and Applications toward In Vitro/ In Vivo Gene Delivery. ACS APPLIED BIO MATERIALS 2023. [PMID: 37277159 DOI: 10.1021/acsabm.3c00256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Compaction of calf thymus DNA (ct-DNA) by two cationic gemini surfactants, 12-4-12 and 12-8-12, in the absence and presence of negatively charged SiO2 nanoparticles (NPs) (∼100 nm) has been explored using various techniques. 12-8-12 having a longer hydrophobic spacer induces a greater extent of ct-DNA compaction than 12-4-12, which becomes more efficient with SiO2 NPs. While 50% ct-DNA compaction in the presence of SiO2 NPs occurs at ∼77 nM of 12-8-12 and ∼130 nM of 12-4-12, but a conventional counterpart surfactant, DTAB, does it at its concentration as high as ∼7 μM. Time-resolved fluorescence anisotropy measurements show changes in the rotational dynamics of a fluorescent probe, DAPI, and helix segments in the condensed DNA. Fluorescence lifetime data and ethidium bromide exclusion assays reveal the binding sites of surfactants to ct-DNA. 12-8-12 with SiO2 NPs has shown the highest cell viability (≥90%) and least cell death in the human embryonic kidney (HEK) 293 cell lines in contrast to the cell viability of ≤80% for DTAB. These results show that 12-8-12 with SiO2 NPs has the highest time and dose-dependent cytotoxicity compared to 12-8-12 and 12-4-12 in the murine breast cancer 4T1 cell line. Fluorescence microscopy and flow cytometry are performed for in vitro cellular uptake of YOYO-1-labeled ct-DNA with surfactants and SiO2 NPs using 4T1 cells after 3 and 6 h incubations. The in vivo tumor accumulation studies are carried out using a real-time in vivo imaging system after intravenous injection of the samples into 4T1 tumor-bearing mice. 12-8-12 with SiO2 has delivered the highest amount of ct-DNA in cells and tumors in a time-dependent manner. Thus, the application of a gemini surfactant with a hydrophobic spacer and SiO2 NPs in compacting and delivering ct-DNA to the tumor is proven, warranting its further exploration in nucleic acid therapy for cancer treatment.
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Affiliation(s)
- Sayantan Halder
- Department of Chemistry, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
| | - Milan Paul
- Department of Pharmacy, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
| | - Shalini Dyagala
- Department of Chemistry, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
| | - Rishika Aggrawal
- Department of Chemistry, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai, Maharashtra 400085, India
| | - Swati Biswas
- Department of Pharmacy, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
| | - Subit K Saha
- Department of Chemistry, Birla Institute of Technology & Science (BITS) Pilani, Hyderabad Campus, Hyderabad, Telangana 500078, India
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27
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Ukraintsev A, Kutuzov M, Belousova E, Joyeau M, Golyshev V, Lomzov A, Lavrik O. PARP3 Affects Nucleosome Compaction Regulation. Int J Mol Sci 2023; 24:ijms24109042. [PMID: 37240388 DOI: 10.3390/ijms24109042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/12/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Genome compaction is one of the important subject areas for understanding the mechanisms regulating genes' expression and DNA replication and repair. The basic unit of DNA compaction in the eukaryotic cell is the nucleosome. The main chromatin proteins responsible for DNA compaction have already been identified, but the regulation of chromatin architecture is still extensively studied. Several authors have shown an interaction of ARTD proteins with nucleosomes and proposed that there are changes in the nucleosomes' structure as a result. In the ARTD family, only PARP1, PARP2, and PARP3 participate in the DNA damage response. Damaged DNA stimulates activation of these PARPs, which use NAD+ as a substrate. DNA repair and chromatin compaction need precise regulation with close coordination between them. In this work, we studied the interactions of these three PARPs with nucleosomes by atomic force microscopy, which is a powerful method allowing for direct measurements of geometric characteristics of single molecules. Using this method, we evaluated perturbations in the structure of single nucleosomes after the binding of a PARP. We demonstrated here that PARP3 significantly alters the geometry of nucleosomes, possibly indicating a new function of PARP3 in chromatin compaction regulation.
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Affiliation(s)
- Alexander Ukraintsev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Mikhail Kutuzov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Ekaterina Belousova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Marie Joyeau
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Victor Golyshev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alexander Lomzov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Olga Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
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28
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Guo Q, Wu S, Geschwind DH. Characterization of Gene Regulatory Elements in Human Fetal Cortical Development: Enhancing Our Understanding of Neurodevelopmental Disorders and Evolution. Dev Neurosci 2023; 46:69-83. [PMID: 37231806 DOI: 10.1159/000530929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
The neocortex is the region that most distinguishes human brain from other mammals and primates [Annu Rev Genet. 2021 Nov;55(1):555-81]. Studying the development of human cortex is important in understanding the evolutionary changes occurring in humans relative to other primates, as well as in elucidating mechanisms underlying neurodevelopmental disorders. Cortical development is a highly regulated process, spatially and temporally coordinated by expression of essential transcriptional factors in response to signaling pathways [Neuron. 2019 Sep;103(6):980-1004]. Enhancers are the most well-understood cis-acting, non-protein-coding regulatory elements that regulate gene expression [Nat Rev Genet. 2014 Apr;15(4):272-86]. Importantly, given the conservation of both DNA sequence and molecular function of the majority of proteins across mammals [Genome Res. 2003 Dec;13(12):2507-18], enhancers [Science. 2015 Mar;347(6226):1155-9], which are far more divergent at the sequence level, likely account for the phenotypes that distinguish the human brain by changing the regulation of gene expression. In this review, we will revisit the conceptual framework of gene regulation during human brain development, as well as the evolution of technologies to study transcriptional regulation, with recent advances in genome biology that open a window allowing us to systematically characterize cis-regulatory elements in developing human brain [Hum Mol Genet. 2022 Oct;31(R1):R84-96]. We provide an update on work to characterize the suite of all enhancers in the developing human brain and the implications for understanding neuropsychiatric disorders. Finally, we discuss emerging therapeutic ideas that utilize our emerging knowledge of enhancer function.
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Affiliation(s)
- Qiuyu Guo
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, USA
- Center for Autism Research and Treatment, Semel Institute, University of California Los Angeles, Los Angeles, California, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Sarah Wu
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, USA
| | - Daniel H Geschwind
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, California, USA
- Center for Autism Research and Treatment, Semel Institute, University of California Los Angeles, Los Angeles, California, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Institute of Precision Health, University of California Los Angeles, Los Angeles, California, USA
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29
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Amin A, Kadam S, Mieczkowski J, Ahmed I, Bhat YA, Shah F, Tolstorukov MY, Kingston RE, Padinhateeri R, Wani AH. Disruption of polyhomeotic polymerization decreases nucleosome occupancy and alters genome accessibility. Life Sci Alliance 2023; 6:e202201768. [PMID: 36849253 PMCID: PMC9973501 DOI: 10.26508/lsa.202201768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/16/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023] Open
Abstract
Chromatin attains its three-dimensional (3D) conformation by establishing contacts between different noncontiguous regions. Sterile Alpha Motif (SAM)-mediated polymerization of the polyhomeotic (PH) protein regulates subnuclear clustering of Polycomb Repressive Complex 1 (PRC1) and chromatin topology. The mutations that perturb the ability of the PH to polymerize, disrupt long-range chromatin contacts, alter Hox gene expression, and lead to developmental defects. To understand the underlying mechanism, we combined the experiments and theory to investigate the effect of this SAM domain mutation on nucleosome occupancy and accessibility on a genome wide scale. Our data show that disruption of PH polymerization because of SAM domain mutation decreases nucleosome occupancy and alters accessibility. Polymer simulations investigating the interplay between distant chromatin contacts and nucleosome occupancy, both of which are regulated by PH polymerization, suggest that nucleosome density increases when contacts between different regions of chromatin are established. Taken together, it appears that SAM domain-mediated PH polymerization biomechanically regulates the organization of chromatin at multiple scales from nucleosomes to chromosomes and we suggest that higher order organization can have a top-down causation effect on nucleosome occupancy.
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Affiliation(s)
- Adfar Amin
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Sangram Kadam
- Department of Biosciences and Bioengineering, IIT, Bombay, India
| | - Jakub Mieczkowski
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Ikhlak Ahmed
- CIRI, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Younus A Bhat
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Fouziya Shah
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | | | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | | | - Ajazul H Wani
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
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30
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Yancoskie MN, Maritz C, van Eijk P, Reed SH, Naegeli H. To incise or not and where: SET-domain methyltransferases know. Trends Biochem Sci 2023; 48:321-330. [PMID: 36357311 DOI: 10.1016/j.tibs.2022.10.003] [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: 07/22/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
The concept of the histone code posits that histone modifications regulate gene functions once interpreted by epigenetic readers. A well-studied case is trimethylation of lysine 4 of histone H3 (H3K4me3), which is enriched at gene promoters. However, H3K4me3 marks are not needed for the expression of most genes, suggesting extra roles, such as influencing the 3D genome architecture. Here, we highlight an intriguing analogy between the H3K4me3-dependent induction of double-strand breaks in several recombination events and the impact of this same mark on DNA incisions for the repair of bulky lesions. We propose that Su(var)3-9, Enhancer-of-zeste and Trithorax (SET)-domain methyltransferases generate H3K4me3 to guide nucleases into chromatin spaces, the favorable accessibility of which ensures that DNA break intermediates are readily processed, thereby safeguarding genome stability.
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Affiliation(s)
- Michelle N Yancoskie
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
| | - Corina Maritz
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland
| | - Patrick van Eijk
- Institute of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Simon H Reed
- Institute of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Hanspeter Naegeli
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Zurich, Switzerland.
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31
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Bouligny IM, Maher KR, Grant S. Mechanisms of myeloid leukemogenesis: Current perspectives and therapeutic objectives. Blood Rev 2023; 57:100996. [PMID: 35989139 PMCID: PMC10693933 DOI: 10.1016/j.blre.2022.100996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 01/28/2023]
Abstract
Acute myeloid leukemia (AML) is a heterogeneous hematopoietic neoplasm which results in clonal proliferation of abnormally differentiated hematopoietic cells. In this review, mechanisms contributing to myeloid leukemogenesis are summarized, highlighting aberrations of epigenetics, transcription factors, signal transduction, cell cycling, and the bone marrow microenvironment. The mechanisms contributing to AML are detailed to spotlight recent findings that convey clinical impact. The applications of current and prospective therapeutic targets are accentuated in addition to reviews of treatment paradigms stratified for each characteristic molecular lesion - with a focus on exploring novel treatment approaches and combinations to improve outcomes in AML.
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Affiliation(s)
- Ian M Bouligny
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA.
| | - Keri R Maher
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA.
| | - Steven Grant
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA.
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32
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Regulation, functions and transmission of bivalent chromatin during mammalian development. Nat Rev Mol Cell Biol 2023; 24:6-26. [PMID: 36028557 DOI: 10.1038/s41580-022-00518-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2022] [Indexed: 12/25/2022]
Abstract
Cells differentiate and progress through development guided by a dynamic chromatin landscape that mediates gene expression programmes. During development, mammalian cells display a paradoxical chromatin state: histone modifications associated with gene activation (trimethylated histone H3 Lys4 (H3K4me3)) and with gene repression (trimethylated H3 Lys27 (H3K27me3)) co-occur at promoters of developmental genes. This bivalent chromatin modification state is thought to poise important regulatory genes for expression or repression during cell-lineage specification. In this Review, we discuss recent work that has expanded our understanding of the molecular basis of bivalent chromatin and its contributions to mammalian development. We describe the factors that establish bivalency, especially histone-lysine N-methyltransferase 2B (KMT2B) and Polycomb repressive complex 2 (PRC2), and consider evidence indicating that PRC1 shapes bivalency and may contribute to its transmission between generations. We posit that bivalency is a key feature of germline and embryonic stem cells, as well as other types of stem and progenitor cells. Finally, we discuss the relevance of bivalent chromtin to human development and cancer, and outline avenues of future research.
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33
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Nunez-Vazquez R, Desvoyes B, Gutierrez C. Histone variants and modifications during abiotic stress response. FRONTIERS IN PLANT SCIENCE 2022; 13:984702. [PMID: 36589114 PMCID: PMC9797984 DOI: 10.3389/fpls.2022.984702] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/28/2022] [Indexed: 06/17/2023]
Abstract
Plants have developed multiple mechanisms as an adaptive response to abiotic stresses, such as salinity, drought, heat, cold, and oxidative stress. Understanding these regulatory networks is critical for coping with the negative impact of abiotic stress on crop productivity worldwide and, eventually, for the rational design of strategies to improve plant performance. Plant alterations upon stress are driven by changes in transcriptional regulation, which rely on locus-specific changes in chromatin accessibility. This process encompasses post-translational modifications of histone proteins that alter the DNA-histones binding, the exchange of canonical histones by variants that modify chromatin conformation, and DNA methylation, which has an implication in the silencing and activation of hypervariable genes. Here, we review the current understanding of the role of the major epigenetic modifications during the abiotic stress response and discuss the intricate relationship among them.
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Semprich CI, Davidson L, Amorim Torres A, Patel H, Briscoe J, Metzis V, Storey KG. ERK1/2 signalling dynamics promote neural differentiation by regulating chromatin accessibility and the polycomb repressive complex. PLoS Biol 2022; 20:e3000221. [PMID: 36455041 PMCID: PMC9746999 DOI: 10.1371/journal.pbio.3000221] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 12/13/2022] [Accepted: 10/11/2022] [Indexed: 12/05/2022] Open
Abstract
Fibroblast growth factor (FGF) is a neural inducer in many vertebrate embryos, but how it regulates chromatin organization to coordinate the activation of neural genes is unclear. Moreover, for differentiation to progress, FGF signalling must decline. Why these signalling dynamics are required has not been determined. Here, we show that dephosphorylation of the FGF effector kinase ERK1/2 rapidly increases chromatin accessibility at neural genes in mouse embryos, and, using ATAC-seq in human embryonic stem cell derived spinal cord precursors, we demonstrate that this occurs genome-wide across neural genes. Importantly, ERK1/2 inhibition induces precocious neural gene transcription, and this involves dissociation of the polycomb repressive complex from key gene loci. This takes place independently of subsequent loss of the repressive histone mark H3K27me3 and transcriptional onset. Transient ERK1/2 inhibition is sufficient for the dissociation of the repressive complex, and this is not reversed on resumption of ERK1/2 signalling. Moreover, genomic footprinting of sites identified by ATAC-seq together with ChIP-seq for polycomb protein Ring1B revealed that ERK1/2 inhibition promotes the occupancy of neural transcription factors (TFs) at non-polycomb as well as polycomb associated sites. Together, these findings indicate that ERK1/2 signalling decline promotes global changes in chromatin accessibility and TF binding at neural genes by directing polycomb and other regulators and appears to serve as a gating mechanism that provides directionality to the process of differentiation.
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Affiliation(s)
- Claudia I. Semprich
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Scotland, United Kingdom
| | - Lindsay Davidson
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Scotland, United Kingdom
| | - Adriana Amorim Torres
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Scotland, United Kingdom
| | | | | | - Vicki Metzis
- The Francis Crick Institute, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail: (VM); (KGS)
| | - Kate G. Storey
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Scotland, United Kingdom
- * E-mail: (VM); (KGS)
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35
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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36
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Kim JJ, Kingston RE. Context-specific Polycomb mechanisms in development. Nat Rev Genet 2022; 23:680-695. [PMID: 35681061 PMCID: PMC9933872 DOI: 10.1038/s41576-022-00499-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2022] [Indexed: 12/11/2022]
Abstract
Polycomb group (PcG) proteins are crucial chromatin regulators that maintain repression of lineage-inappropriate genes and are therefore required for stable cell fate. Recent advances show that PcG proteins form distinct multi-protein complexes in various cellular environments, such as in early development, adult tissue maintenance and cancer. This surprising compositional diversity provides the basis for mechanistic diversity. Understanding this complexity deepens and refines the principles of PcG complex recruitment, target-gene repression and inheritance of memory. We review how the core molecular mechanism of Polycomb complexes operates in diverse developmental settings and propose that context-dependent changes in composition and mechanism are essential for proper epigenetic regulation in development.
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Affiliation(s)
- Jongmin J. Kim
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Robert E. Kingston
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,
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37
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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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38
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Dimitrova E, Feldmann A, van der Weide RH, Flach KD, Lastuvkova A, de Wit E, Klose RJ. Distinct roles for CKM-Mediator in controlling Polycomb-dependent chromosomal interactions and priming genes for induction. Nat Struct Mol Biol 2022; 29:1000-1010. [PMID: 36220895 PMCID: PMC9568430 DOI: 10.1038/s41594-022-00840-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 08/22/2022] [Indexed: 11/20/2022]
Abstract
Precise control of gene expression underpins normal development. This relies on mechanisms that enable communication between gene promoters and other regulatory elements. In embryonic stem cells (ESCs), the cyclin-dependent kinase module Mediator complex (CKM-Mediator) has been reported to physically link gene regulatory elements to enable gene expression and also prime genes for induction during differentiation. Here, we show that CKM-Mediator contributes little to three-dimensional genome organization in ESCs, but it has a specific and essential role in controlling interactions between inactive gene regulatory elements bound by Polycomb repressive complexes (PRCs). These interactions are established by the canonical PRC1 (cPRC1) complex but rely on CKM-Mediator, which facilitates binding of cPRC1 to its target sites. Importantly, through separation-of-function experiments, we reveal that this collaboration between CKM-Mediator and cPRC1 in creating long-range interactions does not function to prime genes for induction during differentiation. Instead, we discover that priming relies on an interaction-independent mechanism whereby the CKM supports core Mediator engagement with gene promoters during differentiation to enable gene activation.
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Affiliation(s)
| | - Angelika Feldmann
- Department of Biochemistry, University of Oxford, Oxford, UK
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Robin H van der Weide
- Division of Gene Regulation, Oncode Institute and The Netherlands Cancer Institute, Amsterdam, The Netherlands
- Hubrecht Institute KNAW, Utrecht, The Netherlands
| | - Koen D Flach
- Division of Gene Regulation, Oncode Institute and The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Anna Lastuvkova
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Elzo de Wit
- Division of Gene Regulation, Oncode Institute and The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, UK.
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Li T. The functions of polycomb group proteins in T cells. CELL INSIGHT 2022; 1:100048. [PMID: 37193554 PMCID: PMC10120301 DOI: 10.1016/j.cellin.2022.100048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 05/18/2023]
Abstract
T cells are involved in many aspects of adaptive immunity, including autoimmunity, anti-tumor activity, and responses to allergenic substances and pathogens. T cells undergo comprehensive epigenome remodeling in response to signals. Polycomb group (PcG) proteins are a well-studied complex of chromatin regulators, conserved in animals, and function in various biological processes. PcG proteins are divided into two distinct complexes: PRC1 (Polycomb repressive complex 1) and PRC2. PcG is correlated with the regulation of T cell development, phenotypic transformation, and function. In contrast, PcG dysregulation is correlated with pathogenesis of immune-mediated diseases and compromised anti-tumor responses. This review discusses recent findings on the involvement of PcG proteins in T cell maturation, differentiation, and activation. In addition, we explore implications in the development of the immune system diseases and cancer immunity, which offers promising targets for various treatment protocols.
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Affiliation(s)
- Ting Li
- Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
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40
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Bonnet J, Boichenko I, Kalb R, Le Jeune M, Maltseva S, Pieropan M, Finkl K, Fierz B, Müller J. PR-DUB preserves Polycomb repression by preventing excessive accumulation of H2Aub1, an antagonist of chromatin compaction. Genes Dev 2022; 36:1046-1061. [PMID: 36357125 PMCID: PMC9744231 DOI: 10.1101/gad.350014.122] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 11/12/2022]
Abstract
The Polycomb repressive complexes PRC1, PRC2, and PR-DUB repress target genes by modifying their chromatin. In Drosophila, PRC1 compacts chromatin and monoubiquitinates histone H2A at lysine 118 (H2Aub1), whereas PR-DUB is a major H2Aub1 deubiquitinase, but how H2Aub1 levels must be balanced for Polycomb repression remains unclear. We show that in early embryos, H2Aub1 is enriched at Polycomb target genes, where it facilitates H3K27me3 deposition by PRC2 to mark genes for repression. During subsequent stages of development, H2Aub1 becomes depleted from these genes and is no longer enriched when Polycomb maintains them repressed. Accordingly, Polycomb targets remain repressed in H2Aub1-deficient animals. In PR-DUB catalytic mutants, high levels of H2Aub1 accumulate at Polycomb target genes, and Polycomb repression breaks down. These high H2Aub1 levels do not diminish Polycomb protein complex binding or H3K27 trimethylation but increase DNA accessibility. We show that H2Aub1 interferes with nucleosome stacking and chromatin fiber folding in vitro. Consistent with this, Polycomb repression defects in PR-DUB mutants are exacerbated by reducing PRC1 chromatin compaction activity, but Polycomb repression is restored if PRC1 E3 ligase activity is removed. PR-DUB therefore acts as a rheostat that removes excessive H2Aub1 that, although deposited by PRC1, antagonizes PRC1-mediated chromatin compaction.
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Affiliation(s)
- Jacques Bonnet
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Iulia Boichenko
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Reinhard Kalb
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mathilde Le Jeune
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Svetlana Maltseva
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mattia Pieropan
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Katja Finkl
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Beat Fierz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jürg Müller
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
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41
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Medina EA, Delma CR, Yang FC. ASXL1/2 mutations and myeloid malignancies. J Hematol Oncol 2022; 15:127. [PMID: 36068610 PMCID: PMC9450349 DOI: 10.1186/s13045-022-01336-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/04/2022] [Indexed: 11/10/2022] Open
Abstract
Myeloid malignancies develop through the accumulation of genetic and epigenetic alterations that dysregulate hematopoietic stem cell (HSC) self-renewal, stimulate HSC proliferation and result in differentiation defects. The polycomb group (PcG) and trithorax group (TrxG) of epigenetic regulators act antagonistically to regulate the expression of genes key to stem cell functions. The genes encoding these proteins, and the proteins that interact with them or affect their occupancy at chromatin, are frequently mutated in myeloid malignancies. PcG and TrxG proteins are regulated by Enhancers of Trithorax and Polycomb (ETP) proteins. ASXL1 and ASXL2 are ETP proteins that assemble chromatin modification complexes and transcription factors. ASXL1 mutations frequently occur in myeloid malignancies and are associated with a poor prognosis, whereas ASXL2 mutations frequently occur in AML with t(8;21)/RUNX1-RUNX1T1 and less frequently in other subtypes of myeloid malignancies. Herein, we review the role of ASXL1 and ASXL2 in normal and malignant hematopoiesis by summarizing the findings of mouse model systems and discussing their underlying molecular mechanisms.
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Affiliation(s)
- Edward A Medina
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA.
| | - Caroline R Delma
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA
| | - Feng-Chun Yang
- Department of Cell Systems and Anatomy, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, 78229, USA.,Mays Cancer Center, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
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42
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German B, Ellis L. Polycomb Directed Cell Fate Decisions in Development and Cancer. EPIGENOMES 2022; 6:28. [PMID: 36135315 PMCID: PMC9497807 DOI: 10.3390/epigenomes6030028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/01/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
The polycomb group (PcG) proteins are a subset of transcription regulators highly conserved throughout evolution. Their principal role is to epigenetically modify chromatin landscapes and control the expression of master transcriptional programs to determine cellular identity. The two mayor PcG protein complexes that have been identified in mammals to date are Polycomb Repressive Complex 1 (PRC1) and 2 (PRC2). These protein complexes selectively repress gene expression via the induction of covalent post-translational histone modifications, promoting chromatin structure stabilization. PRC2 catalyzes the histone H3 methylation at lysine 27 (H3K27me1/2/3), inducing heterochromatin structures. This activity is controlled by the formation of a multi-subunit complex, which includes enhancer of zeste (EZH2), embryonic ectoderm development protein (EED), and suppressor of zeste 12 (SUZ12). This review will summarize the latest insights into how PRC2 in mammalian cells regulates transcription to orchestrate the temporal and tissue-specific expression of genes to determine cell identity and cell-fate decisions. We will specifically describe how PRC2 dysregulation in different cell types can promote phenotypic plasticity and/or non-mutational epigenetic reprogramming, inducing the development of highly aggressive epithelial neuroendocrine carcinomas, including prostate, small cell lung, and Merkel cell cancer. With this, EZH2 has emerged as an important actionable therapeutic target in such cancers.
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Affiliation(s)
- Beatriz German
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Leigh Ellis
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Center for Bioinformatics and Functional Genomics, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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43
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Newar K, Abdulla AZ, Salari H, Fanchon E, Jost D. Dynamical modeling of the H3K27 epigenetic landscape in mouse embryonic stem cells. PLoS Comput Biol 2022; 18:e1010450. [PMID: 36054209 PMCID: PMC9477427 DOI: 10.1371/journal.pcbi.1010450] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 09/15/2022] [Accepted: 07/28/2022] [Indexed: 01/02/2023] Open
Abstract
The Polycomb system via the methylation of the lysine 27 of histone H3 (H3K27) plays central roles in the silencing of many lineage-specific genes during development. Recent experimental evidence suggested that the recruitment of histone modifying enzymes like the Polycomb repressive complex 2 (PRC2) at specific sites and their spreading capacities from these sites are key to the establishment and maintenance of a proper epigenomic landscape around Polycomb-target genes. Here, to test whether such mechanisms, as a minimal set of qualitative rules, are quantitatively compatible with data, we developed a mathematical model that can predict the locus-specific distributions of H3K27 modifications based on previous biochemical knowledge. Within the biological context of mouse embryonic stem cells, our model showed quantitative agreement with experimental profiles of H3K27 acetylation and methylation around Polycomb-target genes in wild-type and mutants. In particular, we demonstrated the key role of the reader-writer module of PRC2 and of the competition between the binding of activating and repressing enzymes in shaping the H3K27 landscape around transcriptional start sites. The predicted dynamics of establishment and maintenance of the repressive trimethylated H3K27 state suggest a slow accumulation, in perfect agreement with experiments. Our approach represents a first step towards a quantitative description of PcG regulation in various cellular contexts and provides a generic framework to better characterize epigenetic regulation in normal or disease situations.
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Affiliation(s)
- Kapil Newar
- Univ Grenoble Alpes, CNRS, TIMC laboratory, UMR 5525, Grenoble, France
| | - Amith Zafal Abdulla
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Lyon, France
| | - Hossein Salari
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Lyon, France
| | - Eric Fanchon
- Univ Grenoble Alpes, CNRS, TIMC laboratory, UMR 5525, Grenoble, France
| | - Daniel Jost
- Univ Grenoble Alpes, CNRS, TIMC laboratory, UMR 5525, Grenoble, France
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Université Claude Bernard Lyon 1, Lyon, France
- * E-mail:
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44
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Millán-Zambrano G, Burton A, Bannister AJ, Schneider R. Histone post-translational modifications - cause and consequence of genome function. Nat Rev Genet 2022; 23:563-580. [PMID: 35338361 DOI: 10.1038/s41576-022-00468-7] [Citation(s) in RCA: 214] [Impact Index Per Article: 107.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2022] [Indexed: 12/16/2022]
Abstract
Much has been learned since the early 1960s about histone post-translational modifications (PTMs) and how they affect DNA-templated processes at the molecular level. This understanding has been bolstered in the past decade by the identification of new types of histone PTM, the advent of new genome-wide mapping approaches and methods to deposit or remove PTMs in a locally and temporally controlled manner. Now, with the availability of vast amounts of data across various biological systems, the functional role of PTMs in important processes (such as transcription, recombination, replication, DNA repair and the modulation of genomic architecture) is slowly emerging. This Review explores the contribution of histone PTMs to the regulation of genome function by discussing when these modifications play a causative (or instructive) role in DNA-templated processes and when they are deposited as a consequence of such processes, to reinforce and record the event. Important advances in the field showing that histone PTMs can exert both direct and indirect effects on genome function are also presented.
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Affiliation(s)
- Gonzalo Millán-Zambrano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Adam Burton
- Institute of Epigenetics and Stem Cells, Helmholtz Center Munich, Munich, Germany
| | - Andrew J Bannister
- Gurdon Institute and Department of Pathology, University of Cambridge, Cambridge, UK.
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Center Munich, Munich, Germany.
- Faculty of Biology, Ludwig Maximilian University (LMU) of Munich, Munich, Germany.
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45
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Doyle EJ, Morey L, Conway E. Know when to fold 'em: Polycomb complexes in oncogenic 3D genome regulation. Front Cell Dev Biol 2022; 10:986319. [PMID: 36105358 PMCID: PMC9464936 DOI: 10.3389/fcell.2022.986319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/04/2022] [Indexed: 11/13/2022] Open
Abstract
Chromatin is spatially and temporally regulated through a series of orchestrated processes resulting in the formation of 3D chromatin structures such as topologically associating domains (TADs), loops and Polycomb Bodies. These structures are closely linked to transcriptional regulation, with loss of control of these processes a frequent feature of cancer and developmental syndromes. One such oncogenic disruption of the 3D genome is through recurrent dysregulation of Polycomb Group Complex (PcG) functions either through genetic mutations, amplification or deletion of genes that encode for PcG proteins. PcG complexes are evolutionarily conserved epigenetic complexes. They are key for early development and are essential transcriptional repressors. PcG complexes include PRC1, PRC2 and PR-DUB which are responsible for the control of the histone modifications H2AK119ub1 and H3K27me3. The spatial distribution of the complexes within the nuclear environment, and their associated modifications have profound effects on the regulation of gene transcription and the 3D genome. Nevertheless, how PcG complexes regulate 3D chromatin organization is still poorly understood. Here we glean insights into the role of PcG complexes in 3D genome regulation and compaction, how these processes go awry during tumorigenesis and the therapeutic implications that result from our insights into these mechanisms.
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Affiliation(s)
- Emma J. Doyle
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
| | - Lluis Morey
- Sylvester Comprehensive Cancer Centre, Miami, FL, United States
- Department of Human Genetics, Biomedical Research Building, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Eric Conway
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
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46
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Chen JJ, Stermer D, Tanny JC. Decoding histone ubiquitylation. Front Cell Dev Biol 2022; 10:968398. [PMID: 36105353 PMCID: PMC9464978 DOI: 10.3389/fcell.2022.968398] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Histone ubiquitylation is a critical part of both active and repressed transcriptional states, and lies at the heart of DNA damage repair signaling. The histone residues targeted for ubiquitylation are often highly conserved through evolution, and extensive functional studies of the enzymes that catalyze the ubiquitylation and de-ubiquitylation of histones have revealed key roles linked to cell growth and division, development, and disease in model systems ranging from yeast to human cells. Nonetheless, the downstream consequences of these modifications have only recently begun to be appreciated on a molecular level. Here we review the structure and function of proteins that act as effectors or “readers” of histone ubiquitylation. We highlight lessons learned about how ubiquitin recognition lends specificity and function to intermolecular interactions in the context of transcription and DNA repair, as well as what this might mean for how we think about histone modifications more broadly.
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47
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Koliopoulos MG, Muhammad R, Roumeliotis TI, Beuron F, Choudhary JS, Alfieri C. Structure of a nucleosome-bound MuvB transcription factor complex reveals DNA remodelling. Nat Commun 2022; 13:5075. [PMID: 36038598 PMCID: PMC9424243 DOI: 10.1038/s41467-022-32798-9] [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: 02/23/2022] [Accepted: 08/15/2022] [Indexed: 01/25/2023] Open
Abstract
Genes encoding the core cell cycle machinery are transcriptionally regulated by the MuvB family of protein complexes in a cell cycle-specific manner. Complexes of MuvB with the transcription factors B-MYB and FOXM1 activate mitotic genes during cell proliferation. The mechanisms of transcriptional regulation by these complexes are still poorly characterised. Here, we combine biochemical analysis and in vitro reconstitution, with structural analysis by cryo-electron microscopy and cross-linking mass spectrometry, to functionally examine these complexes. We find that the MuvB:B-MYB complex binds and remodels nucleosomes, thereby exposing nucleosomal DNA. This remodelling activity is supported by B-MYB which directly binds the remodelled DNA. Given the remodelling activity on the nucleosome, we propose that the MuvB:B-MYB complex functions as a pioneer transcription factor complex. In this work, we rationalise prior biochemical and cellular studies and provide a molecular framework of interactions on a protein complex that is key for cell cycle regulation.
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Affiliation(s)
- Marios G Koliopoulos
- Division of Structural Biology, Chester Beatty Laboratories, The Institute of Cancer Research, London, UK
| | - Reyhan Muhammad
- Division of Structural Biology, Chester Beatty Laboratories, The Institute of Cancer Research, London, UK
| | - Theodoros I Roumeliotis
- Functional Proteomics, Chester Beatty Laboratories, Cancer Biology Division, The Institute of Cancer Research, London, UK
| | - Fabienne Beuron
- Division of Structural Biology, Chester Beatty Laboratories, The Institute of Cancer Research, London, UK
| | - Jyoti S Choudhary
- Functional Proteomics, Chester Beatty Laboratories, Cancer Biology Division, The Institute of Cancer Research, London, UK
| | - Claudio Alfieri
- Division of Structural Biology, Chester Beatty Laboratories, The Institute of Cancer Research, London, UK.
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NODULIN HOMEOBOX is required for heterochromatin homeostasis in Arabidopsis. Nat Commun 2022; 13:5058. [PMID: 36030240 PMCID: PMC9420119 DOI: 10.1038/s41467-022-32709-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 08/11/2022] [Indexed: 11/11/2022] Open
Abstract
Arabidopsis NODULIN HOMEOBOX (NDX) is a nuclear protein described as a regulator of specific euchromatic genes within transcriptionally active chromosome arms. Here we show that NDX is primarily a heterochromatin regulator that functions in pericentromeric regions to control siRNA production and non-CG methylation. Most NDX binding sites coincide with pericentromeric het-siRNA loci that mediate transposon silencing, and are antagonistic with R-loop structures that are prevalent in euchromatic chromosomal arms. Inactivation of NDX leads to differential siRNA accumulation and DNA methylation, of which CHH/CHG hypomethylation colocalizes with NDX binding sites. Hi-C analysis shows significant chromatin structural changes in the ndx mutant, with decreased intrachromosomal interactions at pericentromeres where NDX is enriched in wild-type plants, and increased interchromosomal contacts between KNOT-forming regions, similar to those observed in DNA methylation mutants. We conclude that NDX is a key regulator of heterochromatin that is functionally coupled to het-siRNA loci and non-CG DNA methylation pathways. Arabidopsis NDX was previously reported as a regulator of euchromatic gene expression. Here the authors show that NDX functions at pericentromeric regions and regulates heterochromatin homeostasis by controlling siRNA production and non-CG methylation.
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PRC1-independent binding and activity of RYBP on the KSHV genome during de novo infection. PLoS Pathog 2022; 18:e1010801. [PMID: 36026503 PMCID: PMC9455864 DOI: 10.1371/journal.ppat.1010801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 09/08/2022] [Accepted: 08/08/2022] [Indexed: 11/19/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic virus that causes lifelong infection in humans by establishing latency after primary infection. Latent infection is a prerequisite for both persistent infection and the development of KSHV-associated cancers. While viral lytic genes are transiently expressed after primary infection, their expression is significantly restricted and concomitant with the binding of host epigenetic repressors Polycomb Repressive Complex 1 and 2 (PRC1 and PRC2) to lytic genes. PRC1 and PRC2 mediate the repressive histone marks H2AK119ub and H3K27me3, respectively, and maintain heterochromatin structure on KSHV lytic genes to inhibit their expression. In contrast to PRC2, little is known about the recruitment and role of PRC1 factors on the KSHV genome following de novo infection. Thus, the goal of this study was to examine the function of PRC1 factors in the establishment of KSHV latency. To address this question, we performed an shRNA screen targeting 7 different components of the canonical and non-canonical PRC1 complexes during primary KSHV infection. We found that RYBP, a main subunit of the non-canonical PRC1 complexes, is a potent repressor of KSHV lytic genes that can bind to the viral genome and inhibit lytic genes as early as 4 hours post infection. Surprisingly, our ChIP analyses showed that RYBP binds to lytic viral gene promoters in a PRC1-independent manner, does not affect PRC1 activity on the KSHV genome, and can reduce the level of histone marks associated with transcription elongation. Our data also suggest that RYBP can repress the viral lytic cycle after primary infection by inhibiting the transcription elongation of the lytic cycle inducer KSHV gene RTA. Based on our results we propose that RYBP uses a PRC1-independent mechanism to block KSHV RTA expression thereby promoting the establishment of KSHV latency following de novo infection.
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Critical Roles of Polycomb Repressive Complexes in Transcription and Cancer. Int J Mol Sci 2022; 23:ijms23179574. [PMID: 36076977 PMCID: PMC9455514 DOI: 10.3390/ijms23179574] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022] Open
Abstract
Polycomp group (PcG) proteins are members of highly conserved multiprotein complexes, recognized as gene transcriptional repressors during development and shown to play a role in various physiological and pathological processes. PcG proteins consist of two Polycomb repressive complexes (PRCs) with different enzymatic activities: Polycomb repressive complexes 1 (PRC1), a ubiquitin ligase, and Polycomb repressive complexes 2 (PRC2), a histone methyltransferase. Traditionally, PRCs have been described to be associated with transcriptional repression of homeotic genes, as well as gene transcription activating effects. Particularly in cancer, PRCs have been found to misregulate gene expression, not only depending on the function of the whole PRCs, but also through their separate subunits. In this review, we focused especially on the recent findings in the transcriptional regulation of PRCs, the oncogenic and tumor-suppressive roles of PcG proteins, and the research progress of inhibitors targeting PRCs.
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