1
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Martinez-Mayer J, Brinkmeier ML, O'Connell SP, Ukagwu A, Marti MA, Miras M, Forclaz MV, Benzrihen MG, Cheung LYM, Camper SA, Ellsworth BS, Raetzman LT, Pérez-Millán MI, Davis SW. Knockout mice with pituitary malformations help identify human cases of hypopituitarism. Genome Med 2024; 16:75. [PMID: 38822427 PMCID: PMC11140907 DOI: 10.1186/s13073-024-01347-y] [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: 10/09/2023] [Accepted: 05/20/2024] [Indexed: 06/03/2024] Open
Abstract
BACKGROUND Congenital hypopituitarism (CH) and its associated syndromes, septo-optic dysplasia (SOD) and holoprosencephaly (HPE), are midline defects that cause significant morbidity for affected people. Variants in 67 genes are associated with CH, but a vast majority of CH cases lack a genetic diagnosis. Whole exome and whole genome sequencing of CH patients identifies sequence variants in genes known to cause CH, and in new candidate genes, but many of these are variants of uncertain significance (VUS). METHODS The International Mouse Phenotyping Consortium (IMPC) is an effort to establish gene function by knocking-out all genes in the mouse genome and generating corresponding phenotype data. We used mouse embryonic imaging data generated by the Deciphering Mechanisms of Developmental Disorders (DMDD) project to screen 209 embryonic lethal and sub-viable knockout mouse lines for pituitary malformations. RESULTS Of the 209 knockout mouse lines, we identified 51 that have embryonic pituitary malformations. These genes not only represent new candidates for CH, but also reveal new molecular pathways not previously associated with pituitary organogenesis. We used this list of candidate genes to mine whole exome sequencing data of a cohort of patients with CH, and we identified variants in two unrelated cases for two genes, MORC2 and SETD5, with CH and other syndromic features. CONCLUSIONS The screening and analysis of IMPC phenotyping data provide proof-of-principle that recessive lethal mouse mutants generated by the knockout mouse project are an excellent source of candidate genes for congenital hypopituitarism in children.
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Affiliation(s)
- Julian Martinez-Mayer
- Institute of Biosciences, Biotechnology and Translational Biology (iB3), University of Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Buenos Aires, Argentina
| | - Michelle L Brinkmeier
- Department of Human Genetics, University of Michigan, 1241 Catherine St., Ann Arbor, MI, 48109-5618, USA
| | - Sean P O'Connell
- Department of Biological Sciences, University of South Carolina, 715 Sumter St., Columbia, SC, 29208, USA
| | - Arnold Ukagwu
- Department of Physiology, Southern Illinois University, 1135 Lincoln Dr, Carbondale, IL, 62901, USA
| | - Marcelo A Marti
- Instituto de Química Biológica de La Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mirta Miras
- Hospital De Niños de La Santísima Trinidad, Córdoba, Argentina
| | - Maria V Forclaz
- Servicio de Endocrinología, Hospital Posadas, Buenos Aires, Argentina
| | - Maria G Benzrihen
- Servicio de Endocrinología, Hospital Posadas, Buenos Aires, Argentina
| | - Leonard Y M Cheung
- Department of Human Genetics, University of Michigan, 1241 Catherine St., Ann Arbor, MI, 48109-5618, USA
- Department of Physiology and Biophyscis, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Sally A Camper
- Department of Human Genetics, University of Michigan, 1241 Catherine St., Ann Arbor, MI, 48109-5618, USA
| | - Buffy S Ellsworth
- Department of Physiology, Southern Illinois University, 1135 Lincoln Dr, Carbondale, IL, 62901, USA
| | - Lori T Raetzman
- Department of Molecular and Integrative Physiology, University of Illinois, Champaign-Urbana, Urbana, IL, 61801, USA
| | - Maria I Pérez-Millán
- Institute of Biosciences, Biotechnology and Translational Biology (iB3), University of Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Buenos Aires, Argentina.
| | - Shannon W Davis
- Department of Biological Sciences, University of South Carolina, 715 Sumter St., Columbia, SC, 29208, USA.
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2
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Shafiq TA, Yu J, Feng W, Zhang Y, Zhou H, Paulo JA, Gygi SP, Moazed D. Genomic context- and H2AK119 ubiquitination-dependent inheritance of human Polycomb silencing. SCIENCE ADVANCES 2024; 10:eadl4529. [PMID: 38718120 PMCID: PMC11078181 DOI: 10.1126/sciadv.adl4529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/04/2024] [Indexed: 05/12/2024]
Abstract
Polycomb repressive complexes 1 and 2 (PRC1 and 2) are required for heritable repression of developmental genes. The cis- and trans-acting factors that contribute to epigenetic inheritance of mammalian Polycomb repression are not fully understood. Here, we show that, in human cells, ectopically induced Polycomb silencing at initially active developmental genes, but not near ubiquitously expressed housekeeping genes, is inherited for many cell divisions. Unexpectedly, silencing is heritable in cells with mutations in the H3K27me3 binding pocket of the Embryonic Ectoderm Development (EED) subunit of PRC2, which are known to disrupt H3K27me3 recognition and lead to loss of H3K27me3. This mode of inheritance is less stable and requires intact PRC2 and recognition of H2AK119ub1 by PRC1. Our findings suggest that maintenance of Polycomb silencing is sensitive to local genomic context and can be mediated by PRC1-dependent H2AK119ub1 and PRC2 independently of H3K27me3 recognition.
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Affiliation(s)
- Tiasha A. Shafiq
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Juntao Yu
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Wenzhi Feng
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Yizhe Zhang
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Haining Zhou
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Joao A. Paulo
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Steven P. Gygi
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Danesh Moazed
- Department of Cell Biology, Howard Hughes Medical Institute, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
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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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Rawal CC, Loubiere V, Butova NL, Garcia J, Parreno V, Martinez AM, Cavalli G, Chiolo I. Sustained inactivation of the Polycomb PRC1 complex induces DNA repair defects and genomic instability in epigenetic tumors. RESEARCH SQUARE 2024:rs.3.rs-4289524. [PMID: 38746379 PMCID: PMC11092839 DOI: 10.21203/rs.3.rs-4289524/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Cancer initiation and progression are typically associated with the accumulation of driver mutations and genomic instability. However, recent studies demonstrated that cancers can also be purely initiated by epigenetic alterations, without driver mutations. Specifically, a 24-hours transient down-regulation of polyhomeotic (ph-KD), a core component of the Polycomb complex PRC1, is sufficient to drive epigenetically initiated cancers (EICs) in Drosophila, which are proficient in DNA repair and are characterized by a stable genome. Whether genomic instability eventually occurs when PRC1 down-regulation is performed for extended periods of time remains unclear. Here we show that prolonged depletion of a PRC1 component, which mimics cancer initiating events, results in broad dysregulation of DNA replication and repair genes, along with the accumulation of DNA breaks, defective repair, and widespread genomic instability in the cancer tissue. A broad mis-regulation of H2AK118 ubiquitylation and to a lesser extent of H3K27 trimethylation also occurs, and might contribute to these phenotypes. Together, this study supports a model where DNA repair and replication defects amplify the tumorigenic transformation epigenetically induced by PRC1 loss, resulting in genomic instability and cancer progression.
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5
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Cheng Y, Song Z, Fang X, Tang Z. Polycomb repressive complex 2 and its core component EZH2: potential targeted therapeutic strategies for head and neck squamous cell carcinoma. Clin Epigenetics 2024; 16:54. [PMID: 38600608 PMCID: PMC11007890 DOI: 10.1186/s13148-024-01666-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
The polycomb group (PcG) comprises a set of proteins that exert epigenetic regulatory effects and play crucial roles in diverse biological processes, ranging from pluripotency and development to carcinogenesis. Among these proteins, enhancer of zeste homolog 2 (EZH2) stands out as a catalytic component of polycomb repressive complex 2 (PRC2), which plays a role in regulating the expression of homologous (Hox) genes and initial stages of x chromosome inactivation. In numerous human cancers, including head and neck squamous cell carcinoma (HNSCC), EZH2 is frequently overexpressed or activated and has been identified as a negative prognostic factor. Notably, EZH2 emerges as a significant gene involved in regulating the STAT3/HOTAIR axis, influencing HNSCC proliferation, differentiation, and promoting metastasis by modulating related oncogenes in oral cancer. Currently, various small molecule compounds have been developed as inhibitors specifically targeting EZH2 and have gained approval for treating refractory tumors. In this review, we delve into the epigenetic regulation mediated by EZH2/PRC2 in HNSCC, with a specific focus on exploring the potential roles and mechanisms of EZH2, its crucial contribution to targeted drug therapy, and its association with cancer markers and epithelial-mesenchymal transition. Furthermore, we aim to unravel its potential as a therapeutic strategy for oral squamous cell carcinoma.
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Affiliation(s)
- Yuxi Cheng
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China
| | - Zhengzheng Song
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China
| | - Xiaodan Fang
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China.
| | - Zhangui Tang
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China.
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6
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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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7
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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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8
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Arecco N, Mocavini I, Blanco E, Ballaré C, Libman E, Bonnal S, Irimia M, Di Croce L. Alternative splicing decouples local from global PRC2 activity. Mol Cell 2024; 84:1049-1061.e8. [PMID: 38452766 DOI: 10.1016/j.molcel.2024.02.011] [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: 03/01/2023] [Revised: 12/21/2023] [Accepted: 02/12/2024] [Indexed: 03/09/2024]
Abstract
The Polycomb repressive complex 2 (PRC2) mediates epigenetic maintenance of gene silencing in eukaryotes via methylation of histone H3 at lysine 27 (H3K27). Accessory factors define two distinct subtypes, PRC2.1 and PRC2.2, with different actions and chromatin-targeting mechanisms. The mechanisms orchestrating PRC2 assembly are not fully understood. Here, we report that alternative splicing (AS) of PRC2 core component SUZ12 generates an uncharacterized isoform SUZ12-S, which co-exists with the canonical SUZ12-L isoform in virtually all tissues and developmental stages. SUZ12-S drives PRC2.1 formation and favors PRC2 dimerization. While SUZ12-S is necessary and sufficient for the repression of target genes via promoter-proximal H3K27me3 deposition, SUZ12-L maintains global H3K27 methylation levels. Mouse embryonic stem cells (ESCs) lacking either isoform exit pluripotency more slowly and fail to acquire neuronal cell identity. Our findings reveal a physiological mechanism regulating PRC2 assembly and higher-order interactions in eutherians, with impacts on H3K27 methylation and gene repression.
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Affiliation(s)
- Niccolò Arecco
- Systems and Synthetic Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain.
| | - Ivano Mocavini
- Genome Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain
| | - Enrique Blanco
- Genome Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain
| | - Cecilia Ballaré
- Genome Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain
| | - Elina Libman
- Systems and Synthetic Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain
| | - Sophie Bonnal
- Genome Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain
| | - Manuel Irimia
- Systems and Synthetic Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
| | - Luciano Di Croce
- Genome Biology Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Carrer del Doctor Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
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9
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Espinosa-Martínez M, Alcázar-Fabra M, Landeira D. The molecular basis of cell memory in mammals: The epigenetic cycle. SCIENCE ADVANCES 2024; 10:eadl3188. [PMID: 38416817 PMCID: PMC10901381 DOI: 10.1126/sciadv.adl3188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/26/2024] [Indexed: 03/01/2024]
Abstract
Cell memory refers to the capacity of cells to maintain their gene expression program once the initiating environmental signal has ceased. This exceptional feature is key during the formation of mammalian organisms, and it is believed to be in part mediated by epigenetic factors that can endorse cells with the landmarks required to maintain transcriptional programs upon cell duplication. Here, we review current literature analyzing the molecular basis of epigenetic memory in mammals, with a focus on the mechanisms by which transcriptionally repressive chromatin modifications such as methylation of DNA and histone H3 are propagated through mitotic cell divisions. The emerging picture suggests that cellular memory is supported by an epigenetic cycle in which reversible activities carried out by epigenetic regulators in coordination with cell cycle transition create a multiphasic system that can accommodate both maintenance of cell identity and cell differentiation in proliferating stem cell populations.
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Affiliation(s)
- Mencía Espinosa-Martínez
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - María Alcázar-Fabra
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - David Landeira
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
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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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Cookis T, Lydecker A, Sauer P, Kasinath V, Nogales E. Structural basis for the inhibition of PRC2 by active transcription histone posttranslational modifications. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579730. [PMID: 38370759 PMCID: PMC10871338 DOI: 10.1101/2024.02.09.579730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Polycomb repressive complex 2 (PRC2) is an epigenetic regulator essential for embryonic development and maintenance of cell identity that trimethylates histone H3 at lysine 27 (H3K27me3) leading to gene silencing. PRC2 is regulated by association with protein cofactors and crosstalk with histone posttranslational modifications. Trimethylated histone H3 K4 (H3K4me3) and K36 (H3K36me3) localize to sites of active transcription where H3K27me3 is absent and inhibit PRC2 activity through unknown mechanisms. Using cryo-electron microscopy we reveal that histone H3 tails modified with H3K36me3 engage poorly with the PRC2 active site and preclude its effective interaction with chromatin, while the H3K4me3 modification binds to the allosteric site in the EED subunit, acting as an antagonist that competes with allosteric activators required for the spreading of the H3K27me3 repressive mark. Thus, the location along the H3 tail of the H3K4me3 and H3K36me3 modifications allow them to target two essential requirements for efficient trimethylation of histone H3K27. We further show that the JARID2 cofactor modulates PRC2 activity in the presence of these histone modifications.
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Affiliation(s)
- Trinity Cookis
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Alexandria Lydecker
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Paul Sauer
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Vignesh Kasinath
- Department of Biochemistry, University of Colorado, Boulder, CO 80303
| | - Eva Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
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12
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Tong Z, Ai H, Xu Z, He K, Chu GC, Shi Q, Deng Z, Xue Q, Sun M, Du Y, Liang L, Li JB, Pan M, Liu L. Synovial sarcoma X breakpoint 1 protein uses a cryptic groove to selectively recognize H2AK119Ub nucleosomes. Nat Struct Mol Biol 2024; 31:300-310. [PMID: 38177667 DOI: 10.1038/s41594-023-01141-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 09/27/2023] [Indexed: 01/06/2024]
Abstract
The cancer-specific fusion oncoprotein SS18-SSX1 disturbs chromatin accessibility by hijacking the BAF complex from the promoters and enhancers to the Polycomb-repressed chromatin regions. This process relies on the selective recognition of H2AK119Ub nucleosomes by synovial sarcoma X breakpoint 1 (SSX1). However, the mechanism underlying the selective recognition of H2AK119Ub nucleosomes by SSX1 in the absence of ubiquitin (Ub)-binding capacity remains unknown. Here we report the cryo-EM structure of SSX1 bound to H2AK119Ub nucleosomes at 3.1-Å resolution. Combined in vitro biochemical and cellular assays revealed that the Ub recognition by SSX1 is unique and depends on a cryptic basic groove formed by H3 and the Ub motif on the H2AK119 site. Moreover, this unorthodox binding mode of SSX1 induces DNA unwrapping at the entry/exit sites. Together, our results describe a unique mode of site-specific ubiquitinated nucleosome recognition that underlies the specific hijacking of the BAF complex to Polycomb regions by SS18-SSX1 in synovial sarcoma.
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Affiliation(s)
- Zebin Tong
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Huasong Ai
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China.
- Institute of Translational Medicine, School of Pharmacy, School of Chemistry and Chemical Engineering, National Center for Translational Medicine (Shanghai), Shanghai Jiao Tong University, Shanghai, China.
| | - Ziyu Xu
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Kezhang He
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Guo-Chao Chu
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Qiang Shi
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Zhiheng Deng
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Qiaomei Xue
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Maoshen Sun
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Yunxiang Du
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Lujun Liang
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China
- Institute of Translational Medicine, School of Pharmacy, School of Chemistry and Chemical Engineering, National Center for Translational Medicine (Shanghai), Shanghai Jiao Tong University, Shanghai, China
| | - Jia-Bin Li
- College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Man Pan
- Institute of Translational Medicine, School of Pharmacy, School of Chemistry and Chemical Engineering, National Center for Translational Medicine (Shanghai), Shanghai Jiao Tong University, Shanghai, China.
| | - Lei Liu
- Tsinghua-Peking Center for Life Sciences, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Center for Synthetic and Systems Biology, Department of Chemistry, Tsinghua University, Beijing, China.
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13
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Rahman S, Wolberger C. Breaking the K48-chain: linking ubiquitin beyond protein degradation. Nat Struct Mol Biol 2024; 31:216-218. [PMID: 38366227 DOI: 10.1038/s41594-024-01221-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 01/08/2024] [Indexed: 02/18/2024]
Abstract
The discovery of ubiquitin conjugation to lysines and the role of K48-linked polyubiquitin in targeting substrates for proteasomal degradation was followed by revelation of non-degradative roles of ubiquitination and, more recently, of non-canonical covalent ubiquitin linkages. Here we summarize findings of the ever-expanding array of ubiquitin signals and their biological roles.
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Affiliation(s)
- Sanim Rahman
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Cynthia Wolberger
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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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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15
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Miller A, Dasen JS. Establishing and maintaining Hox profiles during spinal cord development. Semin Cell Dev Biol 2024; 152-153:44-57. [PMID: 37029058 PMCID: PMC10524138 DOI: 10.1016/j.semcdb.2023.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023]
Abstract
The chromosomally-arrayed Hox gene family plays central roles in embryonic patterning and the specification of cell identities throughout the animal kingdom. In vertebrates, the relatively large number of Hox genes and pervasive expression throughout the body has hindered understanding of their biological roles during differentiation. Studies on the subtype diversification of spinal motor neurons (MNs) have provided a tractable system to explore the function of Hox genes during differentiation, and have provided an entry point to explore how neuronal fate determinants contribute to motor circuit assembly. Recent work, using both in vitro and in vivo models of MN subtype differentiation, have revealed how patterning morphogens and regulation of chromatin structure determine cell-type specific programs of gene expression. These studies have not only shed light on basic mechanisms of rostrocaudal patterning in vertebrates, but also have illuminated mechanistic principles of gene regulation that likely operate in the development and maintenance of terminal fates in other systems.
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Affiliation(s)
- Alexander Miller
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Jeremy S Dasen
- NYU Neuroscience Institute and Developmental Genetics Programs, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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16
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Keniry A, Blewitt ME. Chromatin-mediated silencing on the inactive X chromosome. Development 2023; 150:dev201742. [PMID: 37991053 DOI: 10.1242/dev.201742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
In mammals, the second X chromosome in females is silenced to enable dosage compensation between XX females and XY males. This essential process involves the formation of a dense chromatin state on the inactive X (Xi) chromosome. There is a wealth of information about the hallmarks of Xi chromatin and the contribution each makes to silencing, leaving the tantalising possibility of learning from this knowledge to potentially remove silencing to treat X-linked diseases in females. Here, we discuss the role of each chromatin feature in the establishment and maintenance of the silent state, which is of crucial relevance for such a goal.
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Affiliation(s)
- Andrew Keniry
- Epigenetics and Development Division, The Walter and Eliza Hall Institute for Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia
- The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Marnie E Blewitt
- Epigenetics and Development Division, The Walter and Eliza Hall Institute for Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia
- The Department of Medical Biology, University of Melbourne, Parkville, VIC 3010, Australia
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17
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Benabdallah NS, Dalal V, Scott RW, Marcous F, Sotiriou A, Kommoss FKF, Pejkovska A, Gaspar L, Wagner L, Sánchez-Rivera FJ, Ta M, Thornton S, Nielsen TO, Underhill TM, Banito A. Aberrant gene activation in synovial sarcoma relies on SSX specificity and increased PRC1.1 stability. Nat Struct Mol Biol 2023; 30:1640-1652. [PMID: 37735617 PMCID: PMC10643139 DOI: 10.1038/s41594-023-01096-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/15/2023] [Indexed: 09/23/2023]
Abstract
The SS18-SSX fusion drives oncogenic transformation in synovial sarcoma by bridging SS18, a member of the mSWI/SNF (BAF) complex, to Polycomb repressive complex 1 (PRC1) target genes. Here we show that the ability of SS18-SSX to occupy H2AK119ub1-rich regions is an intrinsic property of its SSX C terminus, which can be exploited by fusion to transcriptional regulators beyond SS18. Accordingly, SS18-SSX recruitment occurs in a manner that is independent of the core components and catalytic activity of BAF. Alternative SSX fusions are also recruited to H2AK119ub1-rich chromatin and reproduce the expression signatures of SS18-SSX by engaging with transcriptional activators. Variant Polycomb repressive complex 1.1 (PRC1.1) acts as the main depositor of H2AK119ub1 and is therefore required for SS18-SSX occupancy. Importantly, the SSX C terminus not only depends on H2AK119ub1 for localization, but also further increases it by promoting PRC1.1 complex stability. Consequently, high H2AK119ub1 levels are a feature of murine and human synovial sarcomas. These results uncover a critical role for SSX-C in mediating gene deregulation in synovial sarcoma by providing specificity to chromatin and further enabling oncofusion binding by enhancing PRC1.1 stability and H2AK119ub1 deposition.
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Affiliation(s)
- Nezha S Benabdallah
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Vineet Dalal
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - R Wilder Scott
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Fady Marcous
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Afroditi Sotiriou
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Felix K F Kommoss
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
| | - Anastasija Pejkovska
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ludmila Gaspar
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lena Wagner
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Francisco J Sánchez-Rivera
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, Sloan Kettering Institute, New York, NY, USA
| | - Monica Ta
- Department of Pathology and Laboratory Medicine, Vancouver Coastal Health Research Institute and Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Shelby Thornton
- Department of Pathology and Laboratory Medicine, Vancouver Coastal Health Research Institute and Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Torsten O Nielsen
- Department of Pathology and Laboratory Medicine, Vancouver Coastal Health Research Institute and Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - T Michael Underhill
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Ana Banito
- Soft Tissue Sarcoma Research Group, Hopp Children's Cancer Center, Heidelberg (KiTZ), German Cancer Research Center (DKFZ), Heidelberg, Germany.
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18
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Liu W, Zeng Y, Hao X, Wang X, Liu J, Gao T, Wang M, Zhang J, Huo M, Hu T, Ma T, Zhang D, Teng X, Yu H, Zhang M, Yuan B, Huang W, Yang Y, Wang Y. JARID2 coordinates with the NuRD complex to facilitate breast tumorigenesis through response to adipocyte-derived leptin. Cancer Commun (Lond) 2023; 43:1117-1142. [PMID: 37658635 PMCID: PMC10565380 DOI: 10.1002/cac2.12479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 05/21/2023] [Accepted: 08/21/2023] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND Proteins containing the Jumonji C (JmjC) domain participated in tumorigenesis and cancer progression. However, the mechanisms underlying this effect are still poorly understood. Our objective was to investigate the role of Jumonji and the AT-rich interaction domain-containing 2 (JARID2) - a JmjC family protein - in breast cancer, as well as its latent association with obesity. METHODS Immunohistochemistry, The Cancer Genome Atlas, Gene Expression Omnibus, and other databases were used to analyze the expression of JARID2 in breast cancer cells. Growth curve, 5-ethynyl-2-deoxyuridine (EdU), colony formation, and cell invasion experiments were used to detect whether JARID2 affected breast cancer cell proliferation and invasion. Spheroidization-based experiments and xenotumor transplantation in NOD/SCID mice were used to examine the association between JARID2 and breast cancer stemness. RNA-sequencing, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis were used to identify the cell processes in which JARID2 participates. Immunoaffinity purification and silver staining mass spectrometry were conducted to search for proteins that might interact with JARID2. The results were further verified using co-immunoprecipitation and glutathione S-transferase (GST) pull-down experiments. Using chromatin immunoprecipitation (ChIP) sequencing, we sought the target genes that JARID2 and metastasis-associated protein 1 (MTA1) jointly regulated; the results were validated by ChIP-PCR, quantitative ChIP (qChIP) and ChIP-reChIP assays. A coculture experiment was used to explore the interactions between breast cancer cells and adipocytes. RESULTS In this study, we found that JARID2 was highly expressed in multiple types of cancer including breast cancer. JARID2 promoted glycolysis, lipid metabolism, proliferation, invasion, and stemness of breast cancer cells. Furthermore, JARID2 physically interacted with the nucleosome remodeling and deacetylase (NuRD) complex, transcriptionally repressing a series of tumor suppressor genes such as BRCA2 DNA repair associated (BRCA2), RB transcriptional corepressor 1 (RB1), and inositol polyphosphate-4-phosphatase type II B (INPP4B). Additionally, JARID2 expression was regulated by the obesity-associated adipokine leptin via Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway in the breast cancer microenvironment. Analysis of various online databases also indicated that JARID2/MTA1 was associated with a poor prognosis of breast cancer. CONCLUSION Our data indicated that JARID2 promoted breast tumorigenesis and development, confirming JARID2 as a target for cancer treatment.
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Affiliation(s)
- Wei Liu
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Yi Zeng
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
- Department of Biochemistry and Molecular BiologySchool of Basic Medical ScienceSouthwest Medical UniversityLuzhouSichuanP. R. China
| | - Xinhui Hao
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
| | - Xin Wang
- Department of Breast Surgical OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Jiaxiang Liu
- Department of Breast Surgical OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Tianyang Gao
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
| | - Mengdi Wang
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
| | - Jingyao Zhang
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Miaomiao Huo
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Ting Hu
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Tianyu Ma
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Die Zhang
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Xu Teng
- Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchDepartment of Biochemistry and Molecular BiologySchool of Basic Medical SciencesCapital Medical UniversityBeijingP. R. China
| | - Hefen Yu
- Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchDepartment of Biochemistry and Molecular BiologySchool of Basic Medical SciencesCapital Medical UniversityBeijingP. R. China
| | - Min Zhang
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Baowen Yuan
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Wei Huang
- Beijing Key Laboratory of Cancer Invasion and Metastasis ResearchDepartment of Biochemistry and Molecular BiologySchool of Basic Medical SciencesCapital Medical UniversityBeijingP. R. China
| | - Yunkai Yang
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
| | - Yan Wang
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education)Department of Biochemistry and Molecular BiologySchool of Basic Medical SciencesTianjin Medical UniversityTianjinP. R. China
- Key Laboratory of Cancer and MicrobiomeState Key Laboratory of Molecular OncologyNational Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingP. R. China
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19
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Parast SM, Yu D, Chen C, Dickinson AJ, Chang C, Wang H. Recognition of H2AK119ub plays an important role in RSF1-regulated early Xenopus development. Front Cell Dev Biol 2023; 11:1168643. [PMID: 37529237 PMCID: PMC10389277 DOI: 10.3389/fcell.2023.1168643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/07/2023] [Indexed: 08/03/2023] Open
Abstract
Polycomb group (PcG) proteins are key regulators of gene expression and developmental programs via covalent modification of histones, but the factors that interpret histone modification marks to regulate embryogenesis are less studied. We previously identified Remodeling and Spacing Factor 1 (RSF1) as a reader of histone H2A lysine 119 ubiquitination (H2AK119ub), the histone mark deposited by Polycomb Repressive Complex 1 (PRC1). In the current study, we used Xenopus laevis as a model to investigate how RSF1 affects early embryonic development and whether recognition of H2AK119ub is important for the function of RSF1. We showed that knockdown of Xenopus RSF1, rsf1, not only induced gastrulation defects as reported previously, but specific targeted knockdown in prospective neural precursors induced neural and neural crest defects, with reductions of marker genes. In addition, similar to knockdown of PRC1 components in Xenopus, the anterior-posterior neural patterning was affected in rsf1 knockdown embryos. Binding of H2AK119ub appeared to be crucial for rsf1 function, as a construct with deletion of the UAB domain, which is required for RSF1 to recognize the H2AK119ub nucleosomes, failed to rescue rsf1 morphant embryos and was less effective in interfering with early Xenopus development when ectopically expressed. Furthermore, ectopic deposition of H2AK119ub on the Smad2 target gene gsc using a ring1a-smad2 fusion protein led to ectopic recruitment of RSF1. The fusion protein was inefficient in inducing mesodermal markers in the animal region or a secondary axis when expressed in the ventral tissues. Taken together, our results reveal that rsf1 modulates similar developmental processes in early Xenopus embryos as components of PRC1 do, and that RSF1 acts at least partially through binding to the H2AK119ub mark via the UAB domain during development.
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Affiliation(s)
- Saeid Mohammad Parast
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Deli Yu
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Chunxu Chen
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, United States
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
| | - Amanda J. Dickinson
- Department of Biology, College of Humanities and Sciences, Virginia Commonwealth University, Richmond, VA, United States
| | - Chenbei Chang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Hengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
- Department of Internal Medicine, Division of Hematology, Oncology and Palliative Care, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
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20
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Duong P, Ramesh R, Schneider A, Won S, Cooper AJ, Svaren J. Modulation of Schwann cell homeostasis by the BAP1 deubiquitinase. Glia 2023; 71:1466-1480. [PMID: 36790040 PMCID: PMC10073320 DOI: 10.1002/glia.24351] [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: 09/01/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/16/2023]
Abstract
Schwann cell programming during myelination involves transcriptional networks that activate gene expression but also repress genes that are active in neural crest/embryonic differentiation of Schwann cells. We previously found that a Schwann cell-specific deletion of the EED subunit of the Polycomb Repressive Complex (PRC2) led to inappropriate activation of many such genes. Moreover, some of these genes become re-activated in the pro-regenerative response of Schwann cells to nerve injury, and we found premature activation of the nerve injury program in a Schwann cell-specific knockout of Eed. Polycomb-associated histone modifications include H3K27 trimethylation formed by PRC2 and H2AK119 monoubiquitination (H2AK119ub1), deposited by Polycomb repressive complex 1 (PRC1). We recently found dynamic regulation of H2AK119ub1 in Schwann cell genes after injury. Therefore, we hypothesized that H2AK119 deubiquitination modulates the dynamic polycomb repression of genes involved in Schwann cell maturation. To determine the role of H2AK119 deubiquitination, we generated a Schwann cell-specific knockout of the H2AK119 deubiquitinase Bap1 (BRCA1-associated protein). We found that loss of Bap1 causes tomacula formation, decreased axon diameters and eventual loss of myelinated axons. The gene expression changes are accompanied by redistribution of H2AK119ub1 and H3K27me3 modifications to extragenic sites throughout the genome. BAP1 interacts with OGT in the PR-DUB complex, and our data suggest that the PR-DUB complex plays a multifunctional role in repression of the injury program. Overall, our results indicate Bap1 is required to restrict the spread of polycomb-associated histone modifications in Schwann cells and to promote myelin homeostasis in peripheral nerve.
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Affiliation(s)
- Phu Duong
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Raghu Ramesh
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Comparative Biomedical Sciences Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Andrew Schneider
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Seongsik Won
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Aaron J Cooper
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department Of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
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21
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Glancy E, Wang C, Tuck E, Healy E, Amato S, Neikes HK, Mariani A, Mucha M, Vermeulen M, Pasini D, Bracken AP. PRC2.1- and PRC2.2-specific accessory proteins drive recruitment of different forms of canonical PRC1. Mol Cell 2023; 83:1393-1411.e7. [PMID: 37030288 PMCID: PMC10168607 DOI: 10.1016/j.molcel.2023.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 01/19/2023] [Accepted: 03/16/2023] [Indexed: 04/10/2023]
Abstract
Polycomb repressive complex 2 (PRC2) mediates H3K27me3 deposition, which is thought to recruit canonical PRC1 (cPRC1) via chromodomain-containing CBX proteins to promote stable repression of developmental genes. PRC2 forms two major subcomplexes, PRC2.1 and PRC2.2, but their specific roles remain unclear. Through genetic knockout (KO) and replacement of PRC2 subcomplex-specific subunits in naïve and primed pluripotent cells, we uncover distinct roles for PRC2.1 and PRC2.2 in mediating the recruitment of different forms of cPRC1. PRC2.1 catalyzes the majority of H3K27me3 at Polycomb target genes and is sufficient to promote recruitment of CBX2/4-cPRC1 but not CBX7-cPRC1. Conversely, while PRC2.2 is poor at catalyzing H3K27me3, we find that its accessory protein JARID2 is essential for recruitment of CBX7-cPRC1 and the consequent 3D chromatin interactions at Polycomb target genes. We therefore define distinct contributions of PRC2.1- and PRC2.2-specific accessory proteins to Polycomb-mediated repression and uncover a new mechanism for cPRC1 recruitment.
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Affiliation(s)
- Eleanor Glancy
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Cheng Wang
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Ellen Tuck
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Evan Healy
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Simona Amato
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
| | - Hannah K Neikes
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands
| | - Andrea Mariani
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
| | - Marlena Mucha
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands; The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Diego Pasini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Health Sciences, University of Milan, Via A. di Rudini 8, 20142 Milan, Italy
| | - Adrian P Bracken
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
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22
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H2A Ubiquitination Alters H3-tail Dynamics on Linker-DNA to Enhance H3K27 Methylation. J Mol Biol 2023; 435:167936. [PMID: 36610636 DOI: 10.1016/j.jmb.2022.167936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/15/2022] [Accepted: 12/22/2022] [Indexed: 01/06/2023]
Abstract
Polycomb repressive complex 1 (PRC1) and PRC2 are responsible for epigenetic gene regulation. PRC1 ubiquitinates histone H2A (H2Aub), which subsequently promotes PRC2 to introduce the H3 lysine 27 tri-methyl (H3K27me3) repressive chromatin mark. Although this mechanism provides a link between the two key transcriptional repressors, PRC1 and PRC2, it is unknown how histone-tail dynamics contribute to this process. Here, we have examined the effect of H2A ubiquitination and linker-DNA on H3-tail dynamics and H3K27 methylation by PRC2. In naïve nucleosomes, the H3-tail dynamically contacts linker DNA in addition to core DNA, and the linker-DNA is as important for H3K27 methylation as H2A ubiquitination. H2A ubiquitination alters contacts between the H3-tail and DNA to improve the methyltransferase activity of the PRC2-AEBP2-JARID2 complex. Collectively, our data support a model in which H2A ubiquitination by PRC1 synergizes with linker-DNA to hold H3 histone tails poised for their methylation by PRC2-AEBP2-JARID2.
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23
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Nepita I, Piazza S, Ruglioni M, Cristiani S, Bosurgi E, Salvadori T, Vicidomini G, Diaspro A, Castello M, Cerase A, Bianchini P, Storti B, Bizzarri R. On the Advent of Super-Resolution Microscopy in the Realm of Polycomb Proteins. BIOLOGY 2023; 12:374. [PMID: 36979066 PMCID: PMC10044799 DOI: 10.3390/biology12030374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023]
Abstract
The genomes of metazoans are organized at multiple spatial scales, ranging from the double helix of DNA to whole chromosomes. The intermediate genomic scale of kilobases to megabases, which corresponds to the 50-300 nm spatial scale, is particularly interesting, as the 3D arrangement of chromatin is implicated in multiple regulatory mechanisms. In this context, polycomb group (PcG) proteins stand as major epigenetic modulators of chromatin function, acting prevalently as repressors of gene transcription by combining chemical modifications of target histones with physical crosslinking of distal genomic regions and phase separation. The recent development of super-resolution microscopy (SRM) has strongly contributed to improving our comprehension of several aspects of nano-/mesoscale (10-200 nm) chromatin domains. Here, we review the current state-of-the-art SRM applied to PcG proteins, showing that the application of SRM to PcG activity and organization is still quite limited and mainly focused on the 3D assembly of PcG-controlled genomic loci. In this context, SRM approaches have mostly been applied to multilabel fluorescence in situ hybridization (FISH). However, SRM data have complemented the maps obtained from chromosome capture experiments and have opened a new window to observe how 3D chromatin topology is modulated by PcGs.
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Affiliation(s)
- Irene Nepita
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
| | - Simonluca Piazza
- Molecular Microscopy and Spectroscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- R&D Department, Genoa Instruments s.r.l., Via E. Melen 83, 16152 Genova, Italy
| | - Martina Ruglioni
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Sofia Cristiani
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Emanuele Bosurgi
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Tiziano Salvadori
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
| | - Giuseppe Vicidomini
- Molecular Microscopy and Spectroscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
| | - Alberto Diaspro
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- DIFILAB, Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Marco Castello
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- R&D Department, Genoa Instruments s.r.l., Via E. Melen 83, 16152 Genova, Italy
| | - Andrea Cerase
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Strada Statale dell’Abetone Brennero 4, 56123 Pisa, Italy
| | - Paolo Bianchini
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- DIFILAB, Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - Barbara Storti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Ranieri Bizzarri
- Nanoscopy, Istituto Italiano di Tecnologia, Via E. Melen 83, 16152 Genova, Italy
- Department of Surgical, Medical and Molecular Pathology, and Critical Care Medicine, University of Pisa, Via Roma 65, 56126 Pisa, Italy
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
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24
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Changes in PRC1 activity during interphase modulate lineage transition in pluripotent cells. Nat Commun 2023; 14:180. [PMID: 36635295 PMCID: PMC9837203 DOI: 10.1038/s41467-023-35859-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/05/2023] [Indexed: 01/14/2023] Open
Abstract
The potential of pluripotent cells to respond to developmental cues and trigger cell differentiation is enhanced during the G1 phase of the cell cycle, but the molecular mechanisms involved are poorly understood. Variations in polycomb activity during interphase progression have been hypothesized to regulate the cell-cycle-phase-dependent transcriptional activation of differentiation genes during lineage transition in pluripotent cells. Here, we show that recruitment of Polycomb Repressive Complex 1 (PRC1) and associated molecular functions, ubiquitination of H2AK119 and three-dimensional chromatin interactions, are enhanced during S and G2 phases compared to the G1 phase. In agreement with the accumulation of PRC1 at target promoters upon G1 phase exit, cells in S and G2 phases show firmer transcriptional repression of developmental regulator genes that is drastically perturbed upon genetic ablation of the PRC1 catalytic subunit RING1B. Importantly, depletion of RING1B during retinoic acid stimulation interferes with the preference of mouse embryonic stem cells (mESCs) to induce the transcriptional activation of differentiation genes in G1 phase. We propose that incremental enrolment of polycomb repressive activity during interphase progression reduces the tendency of cells to respond to developmental cues during S and G2 phases, facilitating activation of cell differentiation in the G1 phase of the pluripotent cell cycle.
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25
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Integrative Proteome Analysis Revels 3-Hydroxybutyrate Exerts Neuroprotective Effect by Influencing Chromatin Bivalency. Int J Mol Sci 2023; 24:ijms24010868. [PMID: 36614311 PMCID: PMC9821512 DOI: 10.3390/ijms24010868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/13/2022] [Accepted: 12/20/2022] [Indexed: 01/05/2023] Open
Abstract
3-hydroxybutyrate (3OHB) has been proved to act as a neuroprotective molecule in multiple neurodegenerative diseases. Here, we employed a quantitative proteomics approach to assess the changes of the global protein expression pattern of neural cells upon 3OHB administration. In combination with a disease-related, protein-protein interaction network we pinpointed a hub marker, histone lysine 27 trimethylation, which is one of the key epigenetic markers in multiple neurodegenerative diseases. Integrative analysis of transcriptomic and epigenomic datasets highlighted the involvement of bivalent transcription factors in 3OHB-mediated disease protection and its alteration of neuronal development processes. Transcriptomic profiling revealed that 3OHB impaired the fate decision process of neural precursor cells by repressing differentiation and promoting proliferation. Our study provides a new mechanism of 3OHB's neuroprotective effect, in which chromatin bivalency is sensitive to 3OHB alteration and drives its neuroprotective function both in neurodegenerative diseases and in neural development processes.
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26
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Andricovich J, Tzatsos A. Biological Functions of the KDM2 Family of Histone Demethylases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1433:51-68. [PMID: 37751135 DOI: 10.1007/978-3-031-38176-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
The histone lysine demethylase 2 (KDM2) family of α-Ketoglutarate-Fe++-dependent dioxygenases were the first Jumonji-domain-containing proteins reported to harbor demethylase activity. This landmark discovery paved the way for the characterization of more than 25 enzymes capable of demethylating lysine residues on histones-an epigenetic modification previously thought to be irreversible. The KDM2 family is comprised of KDM2A and KDM2B which share significant structural similarities and demethylate lysine 36 on histone H3. However, they exert distinct cellular functions and are frequently deregulated in a broad spectrum of human cancers. With the advent of next generation sequencing and development of genetically engineered mouse models, it was shown that KDM2A and KDM2B play critical roles in stem cell biology, somatic cell reprograming, and organismal development by regulating cell fate and lineage commitment decisions. Thus, understanding the biochemistry and elucidating the context-dependent function of these enzymes is an emerging new frontier for the development of small molecule inhibitors to treat cancer and other diseases.
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Affiliation(s)
- Jaclyn Andricovich
- Cancer Epigenetics Laboratory, George Washington University Cancer Center, 800 22nd St NW, Suite 8850, Washington DC, 20052, USA
| | - Alexandros Tzatsos
- Cancer Epigenetics Laboratory, George Washington University Cancer Center, 800 22nd St NW, Suite 8850, Washington DC, 20052, USA.
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27
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Guo Y, Yu Y, Wang GG. Polycomb Repressive Complex 2 in Oncology. Cancer Treat Res 2023; 190:273-320. [PMID: 38113005 DOI: 10.1007/978-3-031-45654-1_9] [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] [Indexed: 12/21/2023]
Abstract
Dynamic regulation of the chromatin state by Polycomb Repressive Complex 2 (PRC2) provides an important mean for epigenetic gene control that can profoundly influence normal development and cell lineage specification. PRC2 and PRC2-induced methylation of histone H3 lysine 27 (H3K27) are critically involved in a wide range of DNA-templated processes, which at least include transcriptional repression and gene imprinting, organization of three-dimensional chromatin structure, DNA replication and DNA damage response and repair. PRC2-based genome regulation often goes wrong in diseases, notably cancer. This chapter discusses about different modes-of-action through which PRC2 and EZH2, a catalytic subunit of PRC2, mediate (epi)genomic and transcriptomic regulation. We will also discuss about how alteration or mutation of the PRC2 core or axillary component promotes oncogenesis, how post-translational modification regulates functionality of EZH2 and PRC2, and how PRC2 and other epigenetic pathways crosstalk. Lastly, we will briefly touch on advances in targeting EZH2 and PRC2 dependence as cancer therapeutics.
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Affiliation(s)
- Yiran Guo
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Cancer Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
| | - Yao Yu
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Cancer Institute, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Gang Greg Wang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Cancer Institute, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA.
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28
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Masui O, Corbel C, Nagao K, Endo TA, Kezuka F, Diabangouaya P, Nakayama M, Kumon M, Koseki Y, Obuse C, Koseki H, Heard E. Polycomb repressive complexes 1 and 2 are each essential for maintenance of X inactivation in extra-embryonic lineages. Nat Cell Biol 2023; 25:134-144. [PMID: 36635505 DOI: 10.1038/s41556-022-01047-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/08/2022] [Indexed: 01/14/2023]
Abstract
In female mammals, one of the two X chromosomes becomes inactivated during development by X-chromosome inactivation (XCI). Although Polycomb repressive complex (PRC) 1 and PRC2 have both been implicated in gene silencing, their exact roles in XCI during in vivo development have remained elusive. To this end, we have studied mouse embryos lacking either PRC1 or PRC2. Here we demonstrate that the loss of either PRC has a substantial impact on maintenance of gene silencing on the inactive X chromosome (Xi) in extra-embryonic tissues, with overlapping yet different genes affected, indicating potentially independent roles of the two complexes. Importantly, a lack of PRC1 does not affect PRC2/H3K27me3 accumulation and a lack of PRC2 does not impact PRC1/H2AK119ub1 accumulation on the Xi. Thus PRC1 and PRC2 contribute independently to the maintenance of XCI in early post-implantation extra-embryonic lineages, revealing that both Polycomb complexes can be directly involved and differently deployed in XCI.
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Affiliation(s)
- Osamu Masui
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Catherine Corbel
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
| | - Koji Nagao
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Takaho A Endo
- Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Fuyuko Kezuka
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Patricia Diabangouaya
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France
| | - Manabu Nakayama
- Laboratory of Medical Omics Research, Kazusa DNA Research Institute, Kisarazu, Japan
| | - Mami Kumon
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yoko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Haruhiko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan. .,Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
| | - Edith Heard
- Unité de Génétique et Biologie du Développement, Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Paris, France. .,Collège de France, Paris, France. .,European Molecular Biology Laboratory (EMBL), Directors' research unit, Heidelberg, Germany.
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29
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Roles of Polycomb Complexes in the Reconstruction of 3D Genome Architecture during Preimplantation Embryonic Development. Genes (Basel) 2022; 13:genes13122382. [PMID: 36553649 PMCID: PMC9778514 DOI: 10.3390/genes13122382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
The appropriate deployment of developmental programs depends on complex genetic information encoded by genomic DNA sequences and their positioning and contacts in the three-dimensional (3D) space within the nucleus. Current studies using novel techniques including, but not limited to, Hi-C, ChIA-PET, and Hi-ChIP reveal that regulatory elements (Res), such as enhancers and promoters, may participate in the precise regulation of expression of tissue-specific genes important for both embryogenesis and organogenesis by recruiting Polycomb Group (PcG) complexes. PcG complexes usually poise the transcription of developmental genes by forming Polycomb bodies to compact poised enhancers and promoters marked by H3K27me3 in the 3D space. Additionally, recent studies have also uncovered their roles in transcriptional activation. To better understand the full complexities in the mechanisms of how PcG complexes regulate transcription and long-range 3D contacts of enhancers and promoters during developmental programs, we outline novel insights regarding PcG-associated dramatic changes in the 3D chromatin conformation in developmental programs of early embryos and naïve-ground-state transitions of pluripotent embryonic stem cells (ESCs), and highlight the distinct roles of unique and common subunits of canonical and non-canonical PcG complexes in shaping genome architectures and transcriptional programs.
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30
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RINGs, DUBs and Abnormal Brain Growth-Histone H2A Ubiquitination in Brain Development and Disease. EPIGENOMES 2022; 6:epigenomes6040042. [PMID: 36547251 PMCID: PMC9778336 DOI: 10.3390/epigenomes6040042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022] Open
Abstract
During mammalian neurodevelopment, signaling pathways converge upon transcription factors (TFs) to establish appropriate gene expression programmes leading to the production of distinct neural and glial cell types. This process is partially regulated by the dynamic modulation of chromatin states by epigenetic systems, including the polycomb group (PcG) family of co-repressors. PcG proteins form multi-subunit assemblies that sub-divide into distinct, yet functionally related families. Polycomb repressive complexes 1 and 2 (PRC1 and 2) modify the chemical properties of chromatin by covalently modifying histone tails via H2A ubiquitination (H2AK119ub1) and H3 methylation, respectively. In contrast to the PRCs, the Polycomb repressive deubiquitinase (PR-DUB) complex removes H2AK119ub1 from chromatin through the action of the C-terminal hydrolase BAP1. Genetic screening has identified several PcG mutations that are causally associated with a range of congenital neuropathologies associated with both localised and/or systemic growth abnormalities. As PRC1 and PR-DUB hold opposing functions to control H2AK119ub1 levels across the genome, it is plausible that such neurodevelopmental disorders arise through a common mechanism. In this review, we will focus on advancements regarding the composition and opposing molecular functions of mammalian PRC1 and PR-DUB, and explore how their dysfunction contributes to the emergence of neurodevelopmental disorders.
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31
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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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32
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Gong L, Liu X, Jiao L, Yang X, Lemoff A, Liu X. CK2-mediated phosphorylation of SUZ12 promotes PRC2 function by stabilizing enzyme active site. Nat Commun 2022; 13:6781. [PMID: 36351927 PMCID: PMC9645763 DOI: 10.1038/s41467-022-34431-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 10/25/2022] [Indexed: 11/11/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) plays a key role in maintaining cell identity during differentiation. Methyltransferase activity of PRC2 on histone H3 lysine 27 is regulated by diverse cellular mechanisms, including posttranslational modification. Here, we report a unique phosphorylation-dependent mechanism stimulating PRC2 enzymatic activity. Residue S583 of SUZ12 is phosphorylated by casein kinase 2 (CK2) in cells. A crystal structure captures phosphorylation in action: the flexible phosphorylation-dependent stimulation loop harboring S583 becomes engaged with the catalytic SET domain through a phosphoserine-centered interaction network, stabilizing the enzyme active site and in particular S-adenosyl-methionine (SAM)-binding pocket. CK2-mediated S583 phosphorylation promotes catalysis by enhancing PRC2 binding to SAM and nucleosomal substrates and facilitates reporter gene repression. Loss of S583 phosphorylation impedes PRC2 recruitment and H3K27me3 deposition in pluripotent mESCs and compromises the ability of PRC2 to maintain differentiated cell identity.
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Affiliation(s)
- Lihu Gong
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiuli Liu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Lianying Jiao
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
| | - Xin Yang
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xin Liu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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33
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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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Day CA, Hinchcliffe EH, Robinson JP. H3K27me3 in Diffuse Midline Glioma and Epithelial Ovarian Cancer: Opposing Epigenetic Changes Leading to the Same Poor Outcomes. Cells 2022; 11:cells11213376. [PMID: 36359771 PMCID: PMC9655269 DOI: 10.3390/cells11213376] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/29/2022] Open
Abstract
Histone post-translational modifications modulate gene expression through epigenetic gene regulation. The core histone H3 family members, H3.1, H3.2, and H3.3, play a central role in epigenetics. H3 histones can acquire many post-translational modifications, including the trimethylation of H3K27 (H3K27me3), which represses transcription. Triple methylation of H3K27 is performed by the histone methyltransferase Enhancer of Zeste Homologue 2 (EZH2), a component of the Polycomb Repressive Complex 2. Both global increases and decreases in H3K27me3 have been implicated in a wide range of cancer types. Here, we explore how opposing changes in H3K27me3 contribute to cancer by highlighting its role in two vastly different cancer types; (1) a form of glioma known as diffuse midline glioma H3K27-altered and (2) epithelial ovarian cancer. These two cancers vary widely in the age of onset, sex, associated mutations, and cell and organ type. However, both diffuse midline glioma and ovarian cancer have dysregulation of H3K27 methylation, triggering changes to the cancer cell transcriptome. In diffuse midline glioma, the loss of H3K27 methylation is a primary driving factor in tumorigenesis that promotes glial cell stemness and silences tumor suppressor genes. Conversely, hypermethylation of H3K27 occurs in late-stage epithelial ovarian cancer, which promotes tumor vascularization and tumor cell migration. By using each cancer type as a case study, this review emphasizes the importance of H3K27me3 in cancer while demonstrating that the mechanisms of histone H3 modification and subsequent gene expression changes are not a one-size-fits-all across cancer types.
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Affiliation(s)
- Charles A. Day
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
- Mayo Clinic, Rochester, MN 55902, USA
- Correspondence:
| | - Edward H. Hinchcliffe
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - James P. Robinson
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
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35
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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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36
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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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37
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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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38
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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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39
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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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40
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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: 3] [Impact Index Per Article: 1.5] [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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41
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De Novo Polycomb Recruitment and Repressive Domain Formation. EPIGENOMES 2022; 6:epigenomes6030025. [PMID: 35997371 PMCID: PMC9397058 DOI: 10.3390/epigenomes6030025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Every cell of an organism shares the same genome; even so, each cellular lineage owns a different transcriptome and proteome. The Polycomb group proteins (PcG) are essential regulators of gene repression patterning during development and homeostasis. However, it is unknown how the repressive complexes, PRC1 and PRC2, identify their targets and elicit new Polycomb domains during cell differentiation. Classical recruitment models consider the pre-existence of repressive histone marks; still, de novo target binding overcomes the absence of both H3K27me3 and H2AK119ub. The CpG islands (CGIs), non-core proteins, and RNA molecules are involved in Polycomb recruitment. Nonetheless, it is unclear how de novo targets are identified depending on the physiological context and developmental stage and which are the leading players stabilizing Polycomb complexes at domain nucleation sites. Here, we examine the features of de novo sites and the accessory elements bridging its recruitment and discuss the first steps of Polycomb domain formation and transcriptional regulation, comprehended by the experimental reconstruction of the repressive domains through time-resolved genomic analyses in mammals.
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42
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Viitasalo L, Kettunen K, Kankainen M, Niemelä EH, Kiiski K. A novel partial de novo duplication of JARID2 gene causing a neurodevelopmental phenotype. Mol Genet Genomic Med 2022; 10:e2037. [PMID: 35979655 PMCID: PMC9651605 DOI: 10.1002/mgg3.2037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 06/03/2022] [Accepted: 07/19/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Deletions covering the entire or partial JARID2 gene as well as pathogenic single nucleotide variants leading to haploinsufficiency of JARID2 have recently been shown to cause a clinically distinct neurodevelopmental syndrome. Here, we present a previously undescribed partial de novo duplication of the JARID2 gene in a patient displaying features similar to those of patients with JARID2 loss-of-function variants. CASE REPORT The index patient presents with abnormalities in gross motor skills and speech development as well as neuropsychiatric disorders. The patient has markedly dark infraorbital circles and slightly prominent supraorbital ridges.Whole-genome sequencing and array comparative genomic hybridization revealed a novel disease-causing variant type, a partial tandem duplication of JARID2, covering the exons 1-7. Furthermore, RNA sequencing validated the increased expression of these exons. Expression alterations were also detected in target genes of the PRC2 complex, in which JARID2 acts as an essential member. CONCLUSION Our data add to the variety of different pathogenic variants associated with JARID2 neurodevelopmental syndrome.
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Affiliation(s)
- Liisa Viitasalo
- HUS Diagnostic Center, Division of Genetics and Clinical Pharmacology, Department of Clinical GeneticsUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Kaisa Kettunen
- HUS Diagnostic Center, Division of Genetics and Clinical Pharmacology, Laboratory of GeneticsUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Matti Kankainen
- HUS Diagnostic Center, Division of Genetics and Clinical Pharmacology, Laboratory of GeneticsUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Elina H. Niemelä
- HUS Diagnostic Center, Division of Genetics and Clinical Pharmacology, Laboratory of GeneticsUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Kirsi Kiiski
- HUS Diagnostic Center, Division of Genetics and Clinical Pharmacology, Laboratory of GeneticsUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
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The Role of Polycomb Proteins in Cell Lineage Commitment and Embryonic Development. EPIGENOMES 2022; 6:epigenomes6030023. [PMID: 35997369 PMCID: PMC9397020 DOI: 10.3390/epigenomes6030023] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Embryonic development is a highly intricate and complex process. Different regulatory mechanisms cooperatively dictate the fate of cells as they progress from pluripotent stem cells to terminally differentiated cell types in tissues. A crucial regulator of these processes is the Polycomb Repressive Complex 2 (PRC2). By catalyzing the mono-, di-, and tri-methylation of lysine residues on histone H3 tails (H3K27me3), PRC2 compacts chromatin by cooperating with Polycomb Repressive Complex 1 (PRC1) and represses transcription of target genes. Proteomic and biochemical studies have revealed two variant complexes of PRC2, namely PRC2.1 which consists of the core proteins (EZH2, SUZ12, EED, and RBBP4/7) interacting with one of the Polycomb-like proteins (MTF2, PHF1, PHF19), and EPOP or PALI1/2, and PRC2.2 which contains JARID2 and AEBP2 proteins. MTF2 and JARID2 have been discovered to have crucial roles in directing and recruiting PRC2 to target genes for repression in embryonic stem cells (ESCs). Following these findings, recent work in the field has begun to explore the roles of different PRC2 variant complexes during different stages of embryonic development, by examining molecular phenotypes of PRC2 mutants in both in vitro (2D and 3D differentiation) and in vivo (knock-out mice) assays, analyzed with modern single-cell omics and biochemical assays. In this review, we discuss the latest findings that uncovered the roles of different PRC2 proteins during cell-fate and lineage specification and extrapolate these findings to define a developmental roadmap for different flavors of PRC2 regulation during mammalian embryonic development.
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Oss-Ronen L, Sarusi T, Cohen I. Histone Mono-Ubiquitination in Transcriptional Regulation and Its Mark on Life: Emerging Roles in Tissue Development and Disease. Cells 2022; 11:cells11152404. [PMID: 35954248 PMCID: PMC9368181 DOI: 10.3390/cells11152404] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 02/06/2023] Open
Abstract
Epigenetic regulation plays an essential role in driving precise transcriptional programs during development and homeostasis. Among epigenetic mechanisms, histone mono-ubiquitination has emerged as an important post-transcriptional modification. Two major histone mono-ubiquitination events are the mono-ubiquitination of histone H2A at lysine 119 (H2AK119ub), placed by Polycomb repressive complex 1 (PRC1), and histone H2B lysine 120 mono-ubiquitination (H2BK120ub), placed by the heteromeric RNF20/RNF40 complex. Both of these events play fundamental roles in shaping the chromatin epigenetic landscape and cellular identity. In this review we summarize the current understandings of molecular concepts behind histone mono-ubiquitination, focusing on their recently identified roles in tissue development and pathologies.
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Affiliation(s)
| | | | - Idan Cohen
- Correspondence: ; Tel.: +972-8-6477593; Fax: +972-8-6477626
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45
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Liu X, Liu X. PRC2, Chromatin Regulation, and Human Disease: Insights From Molecular Structure and Function. Front Oncol 2022; 12:894585. [PMID: 35800061 PMCID: PMC9255955 DOI: 10.3389/fonc.2022.894585] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/17/2022] [Indexed: 01/25/2023] Open
Abstract
Polycomb repressive complex 2 (PRC2) is a multisubunit histone-modifying enzyme complex that mediates methylation of histone H3 lysine 27 (H3K27). Trimethylated H3K27 (H3K27me3) is an epigenetic hallmark of gene silencing. PRC2 plays a crucial role in a plethora of fundamental biological processes, and PRC2 dysregulation has been repeatedly implicated in cancers and developmental disorders. Here, we review the current knowledge on mechanisms of cellular regulation of PRC2 function, particularly regarding H3K27 methylation and chromatin targeting. PRC2-related disease mechanisms are also discussed. The mode of action of PRC2 in gene regulation is summarized, which includes competition between H3K27 methylation and acetylation, crosstalk with transcription machinery, and formation of high-order chromatin structure. Recent progress in the structural biology of PRC2 is highlighted from the aspects of complex assembly, enzyme catalysis, and chromatin recruitment, which together provide valuable insights into PRC2 function in close-to-atomic detail. Future studies on the molecular function and structure of PRC2 in the context of native chromatin and in the presence of other regulators like RNAs will continue to deepen our understanding of the stability and plasticity of developmental transcriptional programs broadly impacted by PRC2.
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46
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Dossin F, Heard E. The Molecular and Nuclear Dynamics of X-Chromosome Inactivation. Cold Spring Harb Perspect Biol 2022; 14:a040196. [PMID: 34312245 PMCID: PMC9121902 DOI: 10.1101/cshperspect.a040196] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In female eutherian mammals, dosage compensation of X-linked gene expression is achieved during development through transcriptional silencing of one of the two X chromosomes. Following X chromosome inactivation (XCI), the inactive X chromosome remains faithfully silenced throughout somatic cell divisions. XCI is dependent on Xist, a long noncoding RNA that coats and silences the X chromosome from which it is transcribed. Xist coating triggers a cascade of chromosome-wide changes occurring at the levels of transcription, chromatin composition, chromosome structure, and spatial organization within the nucleus. XCI has emerged as a paradigm for the study of such crucial nuclear processes and the dissection of their functional interplay. In the past decade, the advent of tools to characterize and perturb these processes have provided an unprecedented understanding into their roles during XCI. The mechanisms orchestrating the initiation of XCI as well as its maintenance are thus being unraveled, although many questions still remain. Here, we introduce key aspects of the XCI process and review the recent discoveries about its molecular basis.
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Affiliation(s)
- François Dossin
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
| | - Edith Heard
- European Molecular Biology Laboratory, Director's Unit, 69117 Heidelberg, Germany
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47
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Owen BM, Davidovich C. DNA binding by polycomb-group proteins: searching for the link to CpG islands. Nucleic Acids Res 2022; 50:4813-4839. [PMID: 35489059 PMCID: PMC9122586 DOI: 10.1093/nar/gkac290] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/25/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Polycomb group proteins predominantly exist in polycomb repressive complexes (PRCs) that cooperate to maintain the repressed state of thousands of cell-type-specific genes. Targeting PRCs to the correct sites in chromatin is essential for their function. However, the mechanisms by which PRCs are recruited to their target genes in mammals are multifactorial and complex. Here we review DNA binding by polycomb group proteins. There is strong evidence that the DNA-binding subunits of PRCs and their DNA-binding activities are required for chromatin binding and CpG targeting in cells. In vitro, CpG-specific binding was observed for truncated proteins externally to the context of their PRCs. Yet, the mere DNA sequence cannot fully explain the subset of CpG islands that are targeted by PRCs in any given cell type. At this time we find very little structural and biophysical evidence to support a model where sequence-specific DNA-binding activity is required or sufficient for the targeting of CpG-dinucleotide sequences by polycomb group proteins while they are within the context of their respective PRCs, either PRC1 or PRC2. We discuss the current knowledge and open questions on how the DNA-binding activities of polycomb group proteins facilitate the targeting of PRCs to chromatin.
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Affiliation(s)
- Brady M Owen
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia.,EMBL-Australia, Clayton, VIC, Australia
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48
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BAF complex-mediated chromatin relaxation is required for establishment of X chromosome inactivation. Nat Commun 2022; 13:1658. [PMID: 35351876 PMCID: PMC8964718 DOI: 10.1038/s41467-022-29333-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/10/2022] [Indexed: 12/12/2022] Open
Abstract
The process of epigenetic silencing, while fundamentally important, is not yet completely understood. Here we report a replenishable female mouse embryonic stem cell (mESC) system, Xmas, that allows rapid assessment of X chromosome inactivation (XCI), the epigenetic silencing mechanism of one of the two X chromosomes that enables dosage compensation in female mammals. Through a targeted genetic screen in differentiating Xmas mESCs, we reveal that the BAF complex is required to create nucleosome-depleted regions at promoters on the inactive X chromosome during the earliest stages of establishment of XCI. Without this action gene silencing fails. Xmas mESCs provide a tractable model for screen-based approaches that enable the discovery of unknown facets of the female-specific process of XCI and epigenetic silencing more broadly. Female embryonic stem cells (ESCs) are the ideal model to study X chromosome inactivation (XCI) establishment; however, these cells are challenging to keep in culture. Here the authors create fluorescent ‘Xmas’ reporter mice as a renewable source of ESCs and show nucleosome remodelers Smarcc1 and Smarca4 create a nucleosome-free promoter region prior to the establishment of silencing.
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49
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Taylor-Papadimitriou J, Burchell JM. Histone Methylases and Demethylases Regulating Antagonistic Methyl Marks: Changes Occurring in Cancer. Cells 2022; 11:cells11071113. [PMID: 35406676 PMCID: PMC8997813 DOI: 10.3390/cells11071113] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 02/06/2023] Open
Abstract
Epigenetic regulation of gene expression is crucial to the determination of cell fate in development and differentiation, and the Polycomb (PcG) and Trithorax (TrxG) groups of proteins, acting antagonistically as complexes, play a major role in this regulation. Although originally identified in Drosophila, these complexes are conserved in evolution and the components are well defined in mammals. Each complex contains a protein with methylase activity (KMT), which can add methyl groups to a specific lysine in histone tails, histone 3 lysine 27 (H3K27), by PcG complexes, and H3K4 and H3K36 by TrxG complexes, creating transcriptionally repressive or active marks, respectively. Histone demethylases (KDMs), identified later, added a new dimension to histone methylation, and mutations or changes in levels of expression are seen in both methylases and demethylases and in components of the PcG and TrX complexes across a range of cancers. In this review, we focus on both methylases and demethylases governing the methylation state of the suppressive and active marks and consider their action and interaction in normal tissues and in cancer. A picture is emerging which indicates that the changes which occur in cancer during methylation of histone lysines can lead to repression of genes, including tumour suppressor genes, or to the activation of oncogenes. Methylases or demethylases, which are themselves tumour suppressors, are highly mutated. Novel targets for cancer therapy have been identified and a methylase (KMT6A/EZH2), which produces the repressive H3K27me3 mark, and a demethylase (KDM1A/LSD1), which demethylates the active H3K4me2 mark, are now under clinical evaluation.
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50
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Fitieh A, Locke AJ, Mashayekhi F, Khaliqdina F, Sharma AK, Ismail IH. BMI-1 regulates DNA end resection and homologous recombination repair. Cell Rep 2022; 38:110536. [PMID: 35320715 DOI: 10.1016/j.celrep.2022.110536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/12/2021] [Accepted: 02/28/2022] [Indexed: 11/03/2022] Open
Abstract
BMI-1 is an essential regulator of transcriptional silencing during development. Recently, the role of BMI-1 in the DNA damage response has gained much attention, but the exact mechanism of how BMI-1 participates in the process is unclear. Here, we establish a role for BMI-1 in the repair of DNA double-strand breaks by homologous recombination (HR), where it promotes DNA end resection. Mechanistically, BMI-1 mediates DNA end resection by facilitating the recruitment of CtIP, thus allowing RPA and RAD51 accumulation at DNA damage sites. Interestingly, treatment with transcription inhibitors rescues the DNA end resection defects of BMI-1-depleted cells, suggesting BMI-1-dependent transcriptional silencing mediates DNA end resection. Moreover, we find that H2A ubiquitylation at K119 (H2AK119ub) promotes end resection. Taken together, our results identify BMI-1-mediated transcriptional silencing and promotion of H2AK119ub deposition as essential regulators of DNA end resection and thus the progression of HR.
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Affiliation(s)
- Amira Fitieh
- Biophysics Department, Faculty of Science, Cairo University, 12613 Giza, Egypt; Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Andrew J Locke
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Fatemeh Mashayekhi
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Fajr Khaliqdina
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Ajit K Sharma
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada
| | - Ismail Hassan Ismail
- Biophysics Department, Faculty of Science, Cairo University, 12613 Giza, Egypt; Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada.
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