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Duong P, Rodriguez-Parks A, Kang J, Murphy PJ. CUT&Tag applied to zebrafish adult tail fins reveals a return of embryonic H3K4me3 patterns during regeneration. Epigenetics Chromatin 2024; 17:22. [PMID: 39033118 PMCID: PMC11264793 DOI: 10.1186/s13072-024-00547-5] [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: 03/29/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
Regenerative potential is governed by a complex process of transcriptional reprogramming, involving chromatin reorganization and dynamics in transcription factor binding patterns throughout the genome. The degree to which chromatin and epigenetic changes contribute to this process remains only partially understood. Here we provide a modified CUT&Tag protocol suitable for improved characterization and interrogation of changes in chromatin modifications during adult fin regeneration in zebrafish. Our protocol generates data that recapitulates results from previously published ChIP-Seq methods, requires far fewer cells as input, and significantly improves signal to noise ratios. We deliver high-resolution enrichment maps for H3K4me3 of uninjured and regenerating fin tissues. During regeneration, we find that H3K4me3 levels increase over gene promoters which become transcriptionally active and genes which lose H3K4me3 become silenced. Interestingly, these reprogramming events recapitulate the H3K4me3 patterns observed in developing fin folds of 24-h old zebrafish embryos. Our results indicate that changes in genomic H3K4me3 patterns during fin regeneration occur in a manner consistent with reactivation of developmental programs, demonstrating CUT&Tag to be an effective tool for profiling chromatin landscapes in regenerating tissues.
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Affiliation(s)
- Phu Duong
- Department of Biomedical Genetics, University of Rochester, Rochester, USA
| | | | - Junsu Kang
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, USA.
| | - Patrick J Murphy
- Department of Biomedical Genetics, University of Rochester, Rochester, USA.
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2
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Matlosz S, Franzdóttir SR, Pálsson A, Jónsson ZO. DNA methylation reprogramming in teleosts. Evol Dev 2024:e12486. [PMID: 38783650 DOI: 10.1111/ede.12486] [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: 09/23/2023] [Revised: 04/29/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
Early embryonic development is crucially important but also remarkably diverse among animal taxa. Axis formation and cell lineage specification occur due to both spatial and temporal control of gene expression. This complex system involves various signaling pathways and developmental genes such as transcription factors as well as other molecular interactants that maintain cellular states, including several types of epigenetic marks. 5mC DNA methylation, the chemical modification of cytosines in eukaryotes, represents one such mark. By influencing the compaction of chromatin (a high-order DNA structure), DNA methylation can either repress or induce transcriptional activity. Mammals exhibit a reprogramming of DNA methylation from the parental genomes in the zygote following fertilization, and later in primordial germ cells (PGCs). Whether these periods of methylation reprogramming are evolutionarily conserved, or an innovation in mammals, is an emerging question. Looking into these processes in other vertebrate lineages is thus important, and teleost fish, with their extensive species richness, phenotypic diversity, and multiple rounds of whole genome duplication, provide the perfect research playground for answering such a question. This review aims to present a concise state of the art of DNA methylation reprogramming in early development in fish by summarizing findings from different research groups investigating methylation reprogramming patterns in teleosts, while keeping in mind the ramifications of the methodology used, then comparing those patterns to reprogramming patterns in mammals.
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Affiliation(s)
- Sébastien Matlosz
- Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
| | | | - Arnar Pálsson
- Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
| | - Zophonías O Jónsson
- Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
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3
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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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4
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Guo J, Zou Z, Dou X, Zhao X, Wang Y, Wei L, Pi Y, Wang Y, He C, Guo S. Zebrafish Mbd5 binds to RNA m5C and regulates histone deubiquitylation and gene expression in development metabolism and behavior. Nucleic Acids Res 2024; 52:4257-4275. [PMID: 38366571 PMCID: PMC11077058 DOI: 10.1093/nar/gkae093] [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: 08/19/2023] [Revised: 01/24/2024] [Accepted: 02/05/2024] [Indexed: 02/18/2024] Open
Abstract
Complex biological processes are regulated by both genetic and epigenetic programs. One class of epigenetic modifications is methylation. Evolutionarily conserved methyl-CpG-binding domain (MBD)-containing proteins are known as readers of DNA methylation. MBD5 is linked to multiple human diseases but its mechanism of action remains unclear. Here we report that the zebrafish Mbd5 does not bind to methylated DNA; but rather, it directly binds to 5-methylcytosine (m5C)-modified mRNAs and regulates embryonic development, erythrocyte differentiation, iron metabolism, and behavior. We further show that Mbd5 facilitates removal of the monoubiquitin mark at histone H2A-K119 through an interaction with the Polycomb repressive deubiquitinase (PR-DUB) complex in vivo. The direct target genes of Mbd5 are enriched with both RNA m5C and H2A-K119 ubiquitylation signals. Together, we propose that zebrafish MBD5 is an RNA m5C reader that potentially links RNA methylation to histone modification and in turn transcription regulation in vivo.
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Affiliation(s)
- Jianhua Guo
- State Key Laboratory of Genetic Engineering, National Demonstration Center for Experimental Biology Education, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhongyu Zou
- Department of Chemistry and Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoyang Dou
- Department of Chemistry and Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiang Zhao
- Department of Bioengineering and Therapeutic Sciences, Programs in Human Genetics and Biological Sciences, University of California, San Francisco, CA 94143, USA
| | - Yimin Wang
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, No. 399, Wanyuan Road, Minhang District, Shanghai, China
| | - Liqiang Wei
- State Key Laboratory of Genetic Engineering, National Demonstration Center for Experimental Biology Education, School of Life Sciences, Fudan University, Shanghai, China
- Department of Bioengineering and Therapeutic Sciences, Programs in Human Genetics and Biological Sciences, University of California, San Francisco, CA 94143, USA
| | - Yan Pi
- State Key Laboratory of Genetic Engineering, National Demonstration Center for Experimental Biology Education, School of Life Sciences, Fudan University, Shanghai, China
- Department of Bioengineering and Therapeutic Sciences, Programs in Human Genetics and Biological Sciences, University of California, San Francisco, CA 94143, USA
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, No. 399, Wanyuan Road, Minhang District, Shanghai, China
| | - Chuan He
- Department of Chemistry and Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Su Guo
- Department of Bioengineering and Therapeutic Sciences, Programs in Human Genetics and Biological Sciences, University of California, San Francisco, CA 94143, USA
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5
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Duong P, Rodriguez-Parks A, Kang J, Murphy PJ. CUT&Tag Applied to Zebrafish Adult Tail Fins Reveals a Return of Embryonic H3K4me3 Patterns During Regeneration. RESEARCH SQUARE 2024:rs.3.rs-4189493. [PMID: 38645155 PMCID: PMC11030498 DOI: 10.21203/rs.3.rs-4189493/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Regenerative potential is governed by a complex process of transcriptional reprogramming, involving chromatin reorganization and dynamics in transcription factor binding patterns throughout the genome. The degree to which chromatin and epigenetic changes contribute to this process remains partially understood. Here we provide a modified CUT&Tag protocol suitable for improved characterization and interrogation of epigenetic changes during adult fin regeneration in zebrafish. Our protocol generates data that recapitulates results from previously published ChIP-Seq methods, requires far fewer cells as input, and significantly improves signal to noise ratios. We deliver high-resolution enrichment maps for H3K4me3 of uninjured and regenerating fin tissues. During regeneration, we find that H3K4me3 levels increase over gene promoters which become transcriptionally active and genes which lose H3K4me3 become silenced. Interestingly, these epigenetic reprogramming events recapitulate the H3K4me3 patterns observed in developing fin folds of 24-hour old zebrafish embryos. Our results indicate that changes in genomic H3K4me3 patterns during fin regeneration occur in a manner consistent with reactivation of developmental programs, demonstrating CUT&Tag to be an effective tool for profiling chromatin landscapes in regenerating tissues.
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6
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Meng FW, Murphy KE, Makowski CE, Delatte B, Murphy PJ. Competition for H2A.Z underlies the developmental impacts of repetitive element de-repression. Development 2023; 150:dev202338. [PMID: 37938830 PMCID: PMC10651094 DOI: 10.1242/dev.202338] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/10/2023] [Indexed: 11/10/2023]
Abstract
The histone variant H2A.Z is central to early embryonic development, determining transcriptional competency through chromatin regulation of gene promoters and enhancers. In addition to genic loci, we find that H2A.Z resides at a subset of evolutionarily young repetitive elements, including DNA transposons, long interspersed nuclear elements and long terminal repeats, during early zebrafish development. Moreover, increases in H2A.Z occur when repetitive elements become transcriptionally active. Acquisition of H2A.Z corresponds with a reduction in the levels of the repressive histone modification H3K9me3 and a moderate increase in chromatin accessibility. Notably, however, de-repression of repetitive elements also leads to a significant reduction in H2A.Z over non-repetitive genic loci. Genic loss of H2A.Z is accompanied by transcriptional silencing at adjacent coding sequences, but remarkably, these impacts are mitigated by augmentation of total H2A.Z protein via transgenic overexpression. Our study reveals that levels of H2A.Z protein determine embryonic sensitivity to de-repression of repetitive elements, that repetitive elements can function as a nuclear sink for epigenetic factors and that competition for H2A.Z greatly influences overall transcriptional output during development. These findings uncover general mechanisms in which counteractive biological processes underlie phenotypic outcomes.
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Affiliation(s)
- Fanju W. Meng
- University of Rochester Medical Center, Rochester, NY 14642, USA
| | | | | | - Benjamin Delatte
- Advanced Research Laboratory, Active Motif, 1914 Palomar Oaks Way STE 150, Carlsbad, CA 92008, USA
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7
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Fukushima HS, Takeda H, Nakamura R. Incomplete erasure of histone marks during epigenetic reprogramming in medaka early development. Genome Res 2023; 33:572-586. [PMID: 37117034 PMCID: PMC10234297 DOI: 10.1101/gr.277577.122] [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: 12/07/2022] [Accepted: 03/29/2023] [Indexed: 04/30/2023]
Abstract
Epigenetic modifications undergo drastic erasure and reestablishment after fertilization. This reprogramming is required for proper embryonic development and cell differentiation. In mammals, some histone modifications are not completely reprogrammed and play critical roles in later development. In contrast, in nonmammalian vertebrates, most histone modifications are thought to be more intensively erased and reestablished by the stage of zygotic genome activation (ZGA). However, histone modifications that escape reprogramming in nonmammalian vertebrates and their potential functional roles remain unknown. Here, we quantitatively and comprehensively analyzed histone modification dynamics during epigenetic reprogramming in Japanese killifish, medaka (Oryzias latipes) embryos. Our data revealed that H3K27ac, H3K27me3, and H3K9me3 escape complete reprogramming, whereas H3K4 methylation is completely erased during cleavage stage. Furthermore, we experimentally showed the functional roles of such retained modifications at early stages: (i) H3K27ac premarks promoters during the cleavage stage, and inhibition of histone acetyltransferases disrupts proper patterning of H3K4 and H3K27 methylation at CpG-dense promoters, but does not affect chromatin accessibility after ZGA; (ii) H3K9me3 is globally erased but specifically retained at telomeric regions, which is required for maintenance of genomic stability during the cleavage stage. These results expand the understanding of diversity and conservation of reprogramming in vertebrates, and unveil previously uncharacterized functions of histone modifications retained during epigenetic reprogramming.
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Affiliation(s)
- Hiroto S Fukushima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Ryohei Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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8
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Hanot M, Raby L, Völkel P, Le Bourhis X, Angrand PO. The Contribution of the Zebrafish Model to the Understanding of Polycomb Repression in Vertebrates. Int J Mol Sci 2023; 24:ijms24032322. [PMID: 36768643 PMCID: PMC9916924 DOI: 10.3390/ijms24032322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
Polycomb group (PcG) proteins are highly conserved proteins assembled into two major types of complexes, PRC1 and PRC2, involved in the epigenetic silencing of a wide range of gene expression programs regulating cell fate and tissue development. The crucial role of PRC1 and PRC2 in the fundamental cellular processes and their involvement in human pathologies such as cancer attracted intense attention over the last few decades. Here, we review recent advancements regarding PRC1 and PRC2 function using the zebrafish model. We point out that the unique characteristics of the zebrafish model provide an exceptional opportunity to increase our knowledge of the role of the PRC1 and PRC2 complexes in tissue development, in the maintenance of organ integrity and in pathology.
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Affiliation(s)
- Mariette Hanot
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Ludivine Raby
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pamela Völkel
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Xuefen Le Bourhis
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pierre-Olivier Angrand
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
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9
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Regulation, functions and transmission of bivalent chromatin during mammalian development. Nat Rev Mol Cell Biol 2023; 24:6-26. [PMID: 36028557 DOI: 10.1038/s41580-022-00518-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2022] [Indexed: 12/25/2022]
Abstract
Cells differentiate and progress through development guided by a dynamic chromatin landscape that mediates gene expression programmes. During development, mammalian cells display a paradoxical chromatin state: histone modifications associated with gene activation (trimethylated histone H3 Lys4 (H3K4me3)) and with gene repression (trimethylated H3 Lys27 (H3K27me3)) co-occur at promoters of developmental genes. This bivalent chromatin modification state is thought to poise important regulatory genes for expression or repression during cell-lineage specification. In this Review, we discuss recent work that has expanded our understanding of the molecular basis of bivalent chromatin and its contributions to mammalian development. We describe the factors that establish bivalency, especially histone-lysine N-methyltransferase 2B (KMT2B) and Polycomb repressive complex 2 (PRC2), and consider evidence indicating that PRC1 shapes bivalency and may contribute to its transmission between generations. We posit that bivalency is a key feature of germline and embryonic stem cells, as well as other types of stem and progenitor cells. Finally, we discuss the relevance of bivalent chromtin to human development and cancer, and outline avenues of future research.
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10
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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: 41] [Impact Index Per Article: 20.5] [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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11
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Dijkwel Y, Tremethick DJ. The Role of the Histone Variant H2A.Z in Metazoan Development. J Dev Biol 2022; 10:jdb10030028. [PMID: 35893123 PMCID: PMC9326617 DOI: 10.3390/jdb10030028] [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: 05/17/2022] [Revised: 06/12/2022] [Accepted: 06/23/2022] [Indexed: 12/10/2022] Open
Abstract
During the emergence and radiation of complex multicellular eukaryotes from unicellular ancestors, transcriptional systems evolved by becoming more complex to provide the basis for this morphological diversity. The way eukaryotic genomes are packaged into a highly complex structure, known as chromatin, underpins this evolution of transcriptional regulation. Chromatin structure is controlled by a variety of different epigenetic mechanisms, including the major mechanism for altering the biochemical makeup of the nucleosome by replacing core histones with their variant forms. The histone H2A variant H2A.Z is particularly important in early metazoan development because, without it, embryos cease to develop and die. However, H2A.Z is also required for many differentiation steps beyond the stage that H2A.Z-knockout embryos die. H2A.Z can facilitate the activation and repression of genes that are important for pluripotency and differentiation, and acts through a variety of different molecular mechanisms that depend upon its modification status, its interaction with histone and nonhistone partners, and where it is deposited within the genome. In this review, we discuss the current knowledge about the different mechanisms by which H2A.Z regulates chromatin function at various developmental stages and the chromatin remodeling complexes that determine when and where H2A.Z is deposited.
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12
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Hickey GJM, Wike CL, Nie X, Guo Y, Tan M, Murphy PJ, Cairns BR. Establishment of developmental gene silencing by ordered polycomb complex recruitment in early zebrafish embryos. eLife 2022; 11:e67738. [PMID: 34982026 PMCID: PMC8769650 DOI: 10.7554/elife.67738] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 12/29/2021] [Indexed: 12/15/2022] Open
Abstract
Vertebrate embryos achieve developmental competency during zygotic genome activation (ZGA) by establishing chromatin states that silence yet poise developmental genes for subsequent lineage-specific activation. Here, we reveal the order of chromatin states in establishing developmental gene poising in preZGA zebrafish embryos. Poising is established at promoters and enhancers that initially contain open/permissive chromatin with 'Placeholder' nucleosomes (bearing H2A.Z, H3K4me1, and H3K27ac), and DNA hypomethylation. Silencing is initiated by the recruitment of polycomb repressive complex 1 (PRC1), and H2Aub1 deposition by catalytic Rnf2 during preZGA and ZGA stages. During postZGA, H2Aub1 enables Aebp2-containing PRC2 recruitment and H3K27me3 deposition. Notably, preventing H2Aub1 (via Rnf2 inhibition) eliminates recruitment of Aebp2-PRC2 and H3K27me3, and elicits transcriptional upregulation of certain developmental genes during ZGA. However, upregulation is independent of H3K27me3 - establishing H2Aub1 as the critical silencing modification at ZGA. Taken together, we reveal the logic and mechanism for establishing poised/silent developmental genes in early vertebrate embryos.
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Affiliation(s)
- Graham JM Hickey
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
| | - Candice L Wike
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
| | - Xichen Nie
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
| | - Yixuan Guo
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
| | - Mengyao Tan
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
| | - Patrick J Murphy
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
- Department of Biomedical Genetics, Wilmot Cancer Center, University of Rochester School of MedicineRochesterUnited States
| | - Bradley R Cairns
- Howard Hughes Medical Institute, Department of Oncological Sciences and Huntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUnited States
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