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Cheutin T, Cavalli G. Loss of PRC1 induces higher-order opening of Hox loci independently of transcription during Drosophila embryogenesis. Nat Commun 2018; 9:3898. [PMID: 30254245 PMCID: PMC6156336 DOI: 10.1038/s41467-018-05945-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 07/30/2018] [Indexed: 12/14/2022] Open
Abstract
Polycomb-group proteins are conserved chromatin factors that maintain the silencing of key developmental genes, notably the Hox gene clusters, outside of their expression domains. Depletion of Polycomb repressive complex 1 (PRC1) proteins typically results in chromatin unfolding, as well as ectopic transcription. To disentangle these two phenomena, here we analyze the temporal function of two PRC1 proteins, Polyhomeotic (Ph) and Polycomb (Pc), on Hox gene clusters during Drosophila embryogenesis. We show that the absence of Ph or Pc affects the higher-order chromatin folding of Hox clusters prior to ectopic Hox gene transcription, demonstrating that PRC1 primary function during early embryogenesis is to compact its target chromatin. Moreover, the differential effects of Ph and Pc on Hox cluster folding match the differences in ectopic Hox gene expression observed in these two mutants. Our data suggest that PRC1 maintains gene silencing by folding chromatin domains and impose architectural layer to gene regulation. Loss of Polycomb repressive complex 1 (PRC1) proteins usually results in both chromatin unfolding and ectopic transcription. Here, the authors analyze the temporal function of two PRC1 proteins during Drosophila embryogenesis and provide evidence that PRC1 maintains gene silencing by folding chromatin domains.
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Affiliation(s)
- Thierry Cheutin
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France.
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS and the University of Montpellier, Montpellier, France.
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52
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Huang C, Zhu B. Roles of H3K36-specific histone methyltransferases in transcription: antagonizing silencing and safeguarding transcription fidelity. BIOPHYSICS REPORTS 2018; 4:170-177. [PMID: 30310854 PMCID: PMC6153486 DOI: 10.1007/s41048-018-0063-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/15/2018] [Indexed: 12/20/2022] Open
Abstract
Histone H3K36 methylation is well-known for its role in active transcription. In Saccharomyces cerevisiae, H3K36 methylation is mediated solely by SET2 during transcription elongation. In metazoans, multiple H3K36-specific methyltransferases exist and contribute to distinct biochemical activities and subsequent functions. In this review, we focus on the H3K36-specific histone methyltransferases in metazoans, and discuss their enzymatic activity regulation and their roles in antagonizing Polycomb silencing and safeguarding transcription fidelity.
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Affiliation(s)
- Chang Huang
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Bing Zhu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,2College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
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53
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Polycomb repressive complex 1 shapes the nucleosome landscape but not accessibility at target genes. Genome Res 2018; 28:1494-1507. [PMID: 30154222 PMCID: PMC6169895 DOI: 10.1101/gr.237180.118] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 08/27/2018] [Indexed: 12/21/2022]
Abstract
Polycomb group (PcG) proteins are transcriptional repressors that play important roles in regulating gene expression during animal development. In vitro experiments have shown that PcG protein complexes can compact chromatin to limit the activity of chromatin remodeling enzymes and access of the transcriptional machinery to DNA. In fitting with these ideas, gene promoters associated with PcG proteins have been reported to be less accessible than other gene promoters. However, it remains largely untested in vivo whether PcG proteins define chromatin accessibility or other chromatin features. To address this important question, we examine the chromatin accessibility and nucleosome landscape at PcG protein-bound promoters in mouse embryonic stem cells using the assay for transposase accessible chromatin (ATAC)-seq. Combined with genetic ablation strategies, we unexpectedly discover that although PcG protein-occupied gene promoters exhibit reduced accessibility, this does not rely on PcG proteins. Instead, the Polycomb repressive complex 1 (PRC1) appears to play a unique role in driving elevated nucleosome occupancy and decreased nucleosomal spacing in Polycomb chromatin domains. Our new genome-scale observations argue, in contrast to the prevailing view, that PcG proteins do not significantly affect chromatin accessibility and highlight an underappreciated complexity in the relationship between chromatin accessibility, the nucleosome landscape, and PcG-mediated transcriptional repression.
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54
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Xing L, Liu Y, Xu S, Xiao J, Wang B, Deng H, Lu Z, Xu Y, Chong K. Arabidopsis O-GlcNAc transferase SEC activates histone methyltransferase ATX1 to regulate flowering. EMBO J 2018; 37:embj.201798115. [PMID: 30150325 PMCID: PMC6166131 DOI: 10.15252/embj.201798115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 07/21/2018] [Accepted: 07/30/2018] [Indexed: 01/17/2023] Open
Abstract
Post‐translational modification of proteins by O‐linked β‐N‐acetylglucosamine (O‐GlcNAc) is catalyzed by O‐GlcNAc transferases (OGTs). O‐GlcNAc modification of proteins regulates multiple important biological processes in metazoans. However, whether protein O‐GlcNAcylation is involved in epigenetic processes during plant development is largely unknown. Here, we show that loss of function of SECRET AGENT (SEC), an OGT in Arabidopsis, leads to an early flowering phenotype. This results from reduced histone H3 lysine 4 trimethylation (H3K4me3) of FLOWERING LOCUS C (FLC) locus, which encodes a key negative regulator of flowering. SEC activates ARABIDOPSIS HOMOLOG OF TRITHORAX1 (ATX1), a histone lysine methyltransferase (HKMT), through O‐GlcNAc modification to augment ATX1‐mediated H3K4me3 histone modification at FLC locus. SEC transfers an O‐GlcNAc group on Ser947 of ATX1, which resides in the SET domain, thereby activating ATX1. Taken together, these results uncover a novel post‐translational O‐GlcNAc modification‐mediated mechanism for regulation of HKMT activity and establish the function of O‐GlcNAc signaling in epigenetic processes in plants.
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Affiliation(s)
- Lijing Xing
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yan Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,College of Horticulture, Northeast Agricultural University, Harbin, China
| | - Shujuan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jun Xiao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Bo Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Hanwen Deng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhuang Lu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yunyuan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China .,University of Chinese Academy of Sciences, Beijing, China.,National Center for Plant Gene Research, Beijing, China
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55
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Cameron SR, Nandi S, Kahn TG, Barrasa JI, Stenberg P, Schwartz YB. PTE, a novel module to target Polycomb Repressive Complex 1 to the human cyclin D2 ( CCND2) oncogene. J Biol Chem 2018; 293:14342-14358. [PMID: 30068546 DOI: 10.1074/jbc.ra118.005010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Indexed: 11/06/2022] Open
Abstract
Polycomb group proteins are essential epigenetic repressors. They form multiple protein complexes of which two kinds, PRC1 and PRC2, are indispensable for repression. Although much is known about their biochemical properties, how mammalian PRC1 and PRC2 are targeted to specific genes is poorly understood. Here, we establish the cyclin D2 (CCND2) oncogene as a simple model to address this question. We provide the evidence that the targeting of PRC1 to CCND2 involves a dedicated PRC1-targeting element (PTE). The PTE appears to act in concert with an adjacent cytosine-phosphate-guanine (CpG) island to arrange for the robust binding of PRC1 and PRC2 to repressed CCND2 Our findings pave the way to identify sequence-specific DNA-binding proteins implicated in the targeting of mammalian PRC1 complexes and provide novel link between polycomb repression and cancer.
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Affiliation(s)
| | - Soumyadeep Nandi
- From the Department of Molecular Biology and.,the Computational Life Science Cluster (CLiC), Umeå University, 901 87 Umeå, Sweden and
| | | | | | - Per Stenberg
- From the Department of Molecular Biology and.,the Computational Life Science Cluster (CLiC), Umeå University, 901 87 Umeå, Sweden and.,the Division of Chemical, Biological, Radioactive and Nuclear (CBRN) Security and Defence, FOI-Swedish Defence Research Agency, 906 21 Umeå Sweden
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56
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La Fortezza M, Grigolon G, Cosolo A, Pindyurin A, Breimann L, Blum H, van Steensel B, Classen AK. DamID profiling of dynamic Polycomb-binding sites in Drosophila imaginal disc development and tumorigenesis. Epigenetics Chromatin 2018; 11:27. [PMID: 29871666 PMCID: PMC5987561 DOI: 10.1186/s13072-018-0196-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 05/21/2018] [Indexed: 02/06/2023] Open
Abstract
Background Tracking dynamic protein–chromatin interactions in vivo is key to unravel transcriptional and epigenetic transitions in development and disease. However, limited availability and heterogeneous tissue composition of in vivo source material impose challenges on many experimental approaches. Results Here we adapt cell-type-specific DamID-seq profiling for use in Drosophila imaginal discs and make FLP/FRT-based induction accessible to GAL driver-mediated targeting of specific cell lineages. In a proof-of-principle approach, we utilize ubiquitous DamID expression to describe dynamic transitions of Polycomb-binding sites during wing imaginal disc development and in a scrib tumorigenesis model. We identify Atf3 and Ets21C as novel Polycomb target genes involved in scrib tumorigenesis and suggest that target gene regulation by Atf3 and AP-1 transcription factors, as well as modulation of insulator function, plays crucial roles in dynamic Polycomb-binding at target sites. We establish these findings by DamID-seq analysis of wing imaginal disc samples derived from 10 larvae. Conclusions Our study opens avenues for robust profiling of small cell population in imaginal discs in vivo and provides insights into epigenetic changes underlying transcriptional responses to tumorigenic transformation. Electronic supplementary material The online version of this article (10.1186/s13072-018-0196-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marco La Fortezza
- Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2-4, 82152, Planegg, Martinsried, Germany.,Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, 8092, Zurich, Switzerland
| | - Giovanna Grigolon
- Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2-4, 82152, Planegg, Martinsried, Germany.,Department of Health Sciences and Technology, ETH Zurich, Schorenstrasse 16, 8603, Schwerzenbach, Switzerland
| | - Andrea Cosolo
- Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2-4, 82152, Planegg, Martinsried, Germany.,Center for Biological Systems Analysis, Albert-Ludwigs-University Freiburg, Habsburgerstrasse 49, 79104, Freiburg, Germany
| | - Alexey Pindyurin
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Acad. Lavrentiev Ave. 8/2, Novosibirsk, 630090, Russia
| | - Laura Breimann
- Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2-4, 82152, Planegg, Martinsried, Germany.,Max-Delbrück-Center for Molecular Medicine (MDC), Robert-Rössle-Str. 10, 13092, Berlin, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis, Gene Center Munich, Ludwig-Maximilians-University Munich, Feodor-Lynen-Str. 25, 81377, Munich, Germany
| | - Bas van Steensel
- Division Gene Regulation, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Anne-Kathrin Classen
- Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshaderner Strasse 2-4, 82152, Planegg, Martinsried, Germany. .,Center for Biological Systems Analysis, Albert-Ludwigs-University Freiburg, Habsburgerstrasse 49, 79104, Freiburg, Germany.
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57
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Schmähling S, Meiler A, Lee Y, Mohammed A, Finkl K, Tauscher K, Israel L, Wirth M, Philippou-Massier J, Blum H, Habermann B, Imhof A, Song JJ, Müller J. Regulation and function of H3K36 di-methylation by the trithorax-group protein complex AMC. Development 2018. [PMID: 29540501 PMCID: PMC5963871 DOI: 10.1242/dev.163808] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Drosophila Ash1 protein is a trithorax-group (trxG) regulator that antagonizes Polycomb repression at HOX genes. Ash1 di-methylates lysine 36 in histone H3 (H3K36me2) but how this activity is controlled and at which genes it functions is not well understood. We show that Ash1 protein purified from Drosophila exists in a complex with MRG15 and Caf1 that we named AMC. In Drosophila and human AMC, MRG15 binds a conserved FxLP motif near the Ash1 SET domain and stimulates H3K36 di-methylation on nucleosomes. Drosophila MRG15-null and ash1 catalytic mutants show remarkably specific trxG phenotypes: stochastic loss of HOX gene expression and homeotic transformations in adults. In mutants lacking AMC, H3K36me2 bulk levels appear undiminished but H3K36me2 is reduced in the chromatin of HOX and other AMC-regulated genes. AMC therefore appears to act on top of the H3K36me2/me3 landscape generated by the major H3K36 methyltransferases NSD and Set2. Our analyses suggest that H3K36 di-methylation at HOX genes is the crucial physiological function of AMC and the mechanism by which the complex antagonizes Polycomb repression at these genes. Highlighted Article: The trithorax group protein Ash1 and its regulator MRG15 form a multiprotein complex that maintains expression of HOX and other target genes by methylating histone H3 in their chromatin.
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Affiliation(s)
- Sigrun Schmähling
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Arno Meiler
- Max-Planck Institute of Biochemistry, Computational Biology, Am Klopferspitz 18 82152 Martinsried, Germany
| | - Yoonjung Lee
- Korea Advanced Institute of Science and Technology (KAIST), Department of Biological Sciences, Daejeon 34141, Korea
| | - Arif Mohammed
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Katja Finkl
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Katharina Tauscher
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lars Israel
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Marc Wirth
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Julia Philippou-Massier
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Bianca Habermann
- Max-Planck Institute of Biochemistry, Computational Biology, Am Klopferspitz 18 82152 Martinsried, Germany
| | - Axel Imhof
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Ji-Joon Song
- Korea Advanced Institute of Science and Technology (KAIST), Department of Biological Sciences, Daejeon 34141, Korea
| | - Jürg Müller
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
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58
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Rybina OY, Rozovsky YM, Veselkina ER, Pasyukova EG. Polycomb/Trithorax group-dependent regulation of the neuronal gene Lim3 involved in Drosophila lifespan control. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:451-462. [PMID: 29555581 DOI: 10.1016/j.bbagrm.2018.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/18/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022]
Abstract
Molecular mechanisms governing gene expression and defining complex phenotypes are central to understanding the basics of development and aging. Here, we demonstrate that naturally occurring polymorphisms of the Lim3 regulatory region that are associated with variation in gene expression and Drosophila lifespan control are located exclusively in the Polycomb response element (PRE). We find that the Polycomb group (PcG) protein Polycomb (PC) is bound to the PRE only in embryos where Lim3 is present in both repressed and active states. In contrast, the Trithorax group (TrxG) protein absent, small, or homeotic discs 1 (ASH1) is bound downstream of the PRE, to a region adjacent to the Lim3 transcription start site in embryos and adult flies, in which Lim3 is in an active state. Furthermore, mutations in Pc and ash1 genes affect Lim3 expression depending on the structural integrity of the Lim3 PRE, thus confirming functional interactions between these proteins and Lim3 regulatory region. In addition, we demonstrate that the evolutionary conserved Lim3 core promoter provides basic Lim3 expression, whereas structural changes in the Lim3 PRE of distal promoter provide stage-, and tissue-specific Lim3 expression. Therefore, we hypothesize that PcG/TrxG proteins, which are directly involved in Lim3 transcription regulation, participate in lifespan control.
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Affiliation(s)
- Olga Y Rybina
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurtchatov Sq. 2, Moscow 123182, Russia; Federal State-Financed Educational Institution of Higher Professional Education, Moscow State Pedagogical University, M. Pirogovskaya Str. 1/1, Moscow 119991, Russia.
| | - Yakov M Rozovsky
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurtchatov Sq. 2, Moscow 123182, Russia
| | - Ekaterina R Veselkina
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurtchatov Sq. 2, Moscow 123182, Russia
| | - Elena G Pasyukova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurtchatov Sq. 2, Moscow 123182, Russia
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59
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Histone Demethylase Activity of Utx Is Essential for Viability and Regulation of HOX Gene Expression in Drosophila. Genetics 2017; 208:633-637. [PMID: 29247011 PMCID: PMC5788527 DOI: 10.1534/genetics.117.300421] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/12/2017] [Indexed: 12/12/2022] Open
Abstract
The trimethylation of histone H3 at lysine 27 (H3K27me3) by Polycomb Repressive Complex 2 (PRC2) is essential for the repression of Polycomb target genes. However, the role of enzymatic demethylation of H3K27me3 by the KDM6-family demethylases Utx, Uty, and JmjD3 is less clear. Studies in both mice and worms led to the proposal that KDM6 proteins, but not their H3K27me3 demethylase activity, is critical for normal development. Here, we investigated the requirement of the demethylase activity of the single KDM6 family member Utx in Drosophila. We generated Drosophila expressing a full-length but catalytically inactive Utx protein and found that these mutants show the same phenotypes as animals lacking the Utx protein. Specifically, animals lacking maternally deposited active Utx demethylase in the early embryo show stochastic loss of HOX gene expression that appears to be propagated in a clonal fashion. This suggests that Utx demethylase activity is critical for the removal of ectopic H3K27 trimethylation from active HOX genes during the onset of zygotic gene transcription, and thereby prevents the inappropriate installment of long-term repression by Polycomb. Conversely, maternally deposited catalytically active Utx protein suffices to permit animals that lack zygotic expression of enzymatically active Utx to develop into morphologically normal adults, which eclose from the pupal case but die shortly thereafter. Utx demethylase activity is therefore also essential to sustain viability in adult flies. Together, these analyses identify the earliest embryonic stages and the adult stage as two phases during the Drosophila life cycle that critically require H3K27me3 demethylase activity.
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60
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Liu PP, Xu YJ, Teng ZQ, Liu CM. Polycomb Repressive Complex 2: Emerging Roles in the Central Nervous System. Neuroscientist 2017; 24:208-220. [DOI: 10.1177/1073858417747839] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The polycomb repressive complex 2 (PRC2) is responsible for catalyzing both di- and trimethylation of histone H3 at lysine 27 (H3K27me2/3). The subunits of PRC2 are widely expressed in the central nervous system (CNS). PRC2 as well as H3K27me2/3, play distinct roles in neuronal identity, proliferation and differentiation of neural stem/progenitor cells, neuronal morphology, and gliogenesis. Mutations or dysregulations of PRC2 subunits often cause neurological diseases. Therefore, PRC2 might represent a common target of different pathological processes that drive neurodegenerative diseases. A better understanding of the intricate and complex regulatory networks mediated by PRC2 in CNS will help to develop new therapeutic approaches and to generate specific brain cell types for treating neurological diseases.
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Affiliation(s)
- Pei-Pei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Ya-Jie Xu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Zhao-Qian Teng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Chang-Mei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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61
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Pereira A, Paro R. Pho dynamically interacts with Spt5 to facilitate transcriptional switches at the hsp70 locus. Epigenetics Chromatin 2017; 10:57. [PMID: 29208012 PMCID: PMC5718073 DOI: 10.1186/s13072-017-0166-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/29/2017] [Indexed: 11/10/2022] Open
Abstract
Background Numerous target genes of the Polycomb group (PcG) are transiently activated by a stimulus and subsequently repressed. However, mechanisms by which PcG proteins regulate such target genes remain elusive. Results We employed the heat shock-responsive hsp70 locus in Drosophila to study the chromatin dynamics of PRC1 and its interplay with known regulators of the locus before, during and after heat shock. We detected mutually exclusive binding patterns for HSF and PRC1 at the hsp70 locus. We found that Pleiohomeotic (Pho), a DNA-binding PcG member, dynamically interacts with Spt5, an elongation factor. The dynamic interaction switch between Pho and Spt5 is triggered by the recruitment of HSF to chromatin. Mutation in the protein–protein interaction domain (REPO domain) of Pho interferes with the dynamics of its interaction with Spt5. The transcriptional kinetics of the heat shock response is negatively affected by a mutation in the REPO domain of Pho. Conclusions We propose that a dynamic interaction switch between PcG proteins and an elongation factor enables stress-inducible genes to efficiently switch between ON/OFF states in the presence/absence of the activating stimulus. Electronic supplementary material The online version of this article (10.1186/s13072-017-0166-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Allwyn Pereira
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
| | - Renato Paro
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland. .,Faculty of Sciences, University of Basel, 4056, Basel, Switzerland.
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62
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Huang C, Yang F, Zhang Z, Zhang J, Cai G, Li L, Zheng Y, Chen S, Xi R, Zhu B. Mrg15 stimulates Ash1 H3K36 methyltransferase activity and facilitates Ash1 Trithorax group protein function in Drosophila. Nat Commun 2017; 8:1649. [PMID: 29158494 PMCID: PMC5696344 DOI: 10.1038/s41467-017-01897-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 10/23/2017] [Indexed: 12/28/2022] Open
Abstract
Ash1 is a Trithorax group protein that possesses H3K36-specific histone methyltransferase activity, which antagonizes Polycomb silencing. Here we report the identification of two Ash1 complex subunits, Mrg15 and Nurf55. In vitro, Mrg15 stimulates the enzymatic activity of Ash1. In vivo, Mrg15 is recruited by Ash1 to their common targets, and Mrg15 reinforces Ash1 chromatin association and facilitates the proper deposition of H3K36me2. To dissect the functional role of Mrg15 in the context of the Ash1 complex, we identify an Ash1 point mutation (Ash1-R1288A) that displays a greatly attenuated interaction with Mrg15. Knock-in flies bearing this mutation display multiple homeotic transformation phenotypes, and these phenotypes are partially rescued by overexpressing the Mrg15-Nurf55 fusion protein, which stabilizes the association of Mrg15 with Ash1. In summary, Mrg15 is a subunit of the Ash1 complex, a stimulator of Ash1 enzymatic activity and a critical regulator of the TrxG protein function of Ash1 in Drosophila.
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Affiliation(s)
- Chang Huang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fu Yang
- National institute of Biological Sciences, Beijing, 102206, China
| | - Zhuqiang Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Gaihong Cai
- National institute of Biological Sciences, Beijing, 102206, China
| | - Lin Li
- National institute of Biological Sciences, Beijing, 102206, China
| | - Yong Zheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - She Chen
- National institute of Biological Sciences, Beijing, 102206, China
| | - Rongwen Xi
- National institute of Biological Sciences, Beijing, 102206, China.
| | - Bing Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. .,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Kang H, Jung YL, McElroy KA, Zee BM, Wallace HA, Woolnough JL, Park PJ, Kuroda MI. Bivalent complexes of PRC1 with orthologs of BRD4 and MOZ/MORF target developmental genes in Drosophila. Genes Dev 2017; 31:1988-2002. [PMID: 29070704 PMCID: PMC5710143 DOI: 10.1101/gad.305987.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 09/28/2017] [Indexed: 02/05/2023]
Abstract
Kang et al. confirm PRC1–Br140 and PRC1–Fs(1)h interactions and identify their genomic binding sites. PRC1–Br140 bind developmental genes in fly embryos, with analogous co-occupancy of PRC1 and BRD1 at bivalent loci in human ES cells. Regulatory decisions in Drosophila require Polycomb group (PcG) proteins to maintain the silent state and Trithorax group (TrxG) proteins to oppose silencing. Since PcG and TrxG are ubiquitous and lack apparent sequence specificity, a long-standing model is that targeting occurs via protein interactions; for instance, between repressors and PcG proteins. Instead, we found that Pc-repressive complex 1 (PRC1) purifies with coactivators Fs(1)h [female sterile (1) homeotic] and Enok/Br140 during embryogenesis. Fs(1)h is a TrxG member and the ortholog of BRD4, a bromodomain protein that binds to acetylated histones and is a key transcriptional coactivator in mammals. Enok and Br140, another bromodomain protein, are orthologous to subunits of a mammalian MOZ/MORF acetyltransferase complex. Here we confirm PRC1–Br140 and PRC1–Fs(1)h interactions and identify their genomic binding sites. PRC1–Br140 bind developmental genes in fly embryos, with analogous co-occupancy of PRC1 and a Br140 ortholog, BRD1, at bivalent loci in human embryonic stem (ES) cells. We propose that identification of PRC1–Br140 “bivalent complexes” in fly embryos supports and extends the bivalency model posited in mammalian cells, in which the coexistence of H3K4me3 and H3K27me3 at developmental promoters represents a poised transcriptional state. We further speculate that local competition between acetylation and deacetylation may play a critical role in the resolution of bivalent protein complexes during development.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Youngsook L Jung
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kyle A McElroy
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Barry M Zee
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Heather A Wallace
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jessica L Woolnough
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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64
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Choi J, Bachmann AL, Tauscher K, Benda C, Fierz B, Müller J. DNA binding by PHF1 prolongs PRC2 residence time on chromatin and thereby promotes H3K27 methylation. Nat Struct Mol Biol 2017; 24:1039-1047. [DOI: 10.1038/nsmb.3488] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/20/2017] [Indexed: 12/20/2022]
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65
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Sosnik J, Vieira WA, Webster KA, Siegfried KR, McCusker CD. A new and improved algorithm for the quantification of chromatin condensation from microscopic data shows decreased chromatin condensation in regenerating axolotl limb cells. PLoS One 2017; 12:e0185292. [PMID: 29023511 PMCID: PMC5638231 DOI: 10.1371/journal.pone.0185292] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/08/2017] [Indexed: 01/11/2023] Open
Abstract
The nuclear landscape plays an important role in the regulation of tissue and positional specific genes in embryonic and developing cells. Changes in this landscape can be dynamic, and are associated with the differentiation of cells during embryogenesis, and the de-differentiation of cells during induced pluripotent stem cell (iPSC) formation and in many cancers. However, tools to quantitatively characterize these changes are limited, especially in the in vivo context, where numerous tissue types are present and cells are arranged in multiple layers. Previous tools have been optimized for the monolayer nature of cultured cells. Therefore, we present a new algorithm to quantify the condensation of chromatin in two in vivo systems. We first developed this algorithm to quantify changes in chromatin compaction and validated it in differentiating spermatids in zebrafish testes. Our algorithm successfully detected the typical increase in chromatin compaction as these cells differentiate. We then employed the algorithm to quantify the changes that occur in amphibian limb cells as they participate in a regenerative response. We observed that the chromatin in the limb cells de-compacts as they contribute to the regenerating organ. We present this new tool as an open sourced software that can be readily accessed and optimized to quantify chromatin compaction in complex multi-layered samples.
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Affiliation(s)
- Julian Sosnik
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
- Department of Interdisciplinary Engineering, Wentworth Institute of Technology, Boston, Massachusetts, United States of America
| | - Warren A. Vieira
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
| | - Kaitlyn A. Webster
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
| | - Kellee R. Siegfried
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
| | - Catherine D. McCusker
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
- * E-mail:
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66
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Rickels R, Herz HM, Sze CC, Cao K, Morgan MA, Collings CK, Gause M, Takahashi YH, Wang L, Rendleman EJ, Marshall SA, Krueger A, Bartom ET, Piunti A, Smith ER, Abshiru NA, Kelleher NL, Dorsett D, Shilatifard A. Histone H3K4 monomethylation catalyzed by Trr and mammalian COMPASS-like proteins at enhancers is dispensable for development and viability. Nat Genet 2017; 49:1647-1653. [PMID: 28967912 DOI: 10.1038/ng.3965] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 09/01/2017] [Indexed: 12/21/2022]
Abstract
Histone H3 lysine 4 monomethylation (H3K4me1) is an evolutionarily conserved feature of enhancer chromatin catalyzed by the COMPASS-like methyltransferase family, which includes Trr in Drosophila melanogaster and MLL3 (encoded by KMT2C) and MLL4 (encoded by KMT2D) in mammals. Here we demonstrate that Drosophila embryos expressing catalytically deficient Trr eclose and develop to productive adulthood. Parallel experiments with a trr allele that augments enzyme product specificity show that conversion of H3K4me1 at enhancers to H3K4me2 and H3K4me3 is also compatible with life and results in minimal changes in gene expression. Similarly, loss of the catalytic SET domains of MLL3 and MLL4 in mouse embryonic stem cells (mESCs) does not disrupt self-renewal. Drosophila embryos with trr alleles encoding catalytic mutants manifest subtle developmental abnormalities when subjected to temperature stress or altered cohesin levels. Collectively, our findings suggest that animal development can occur in the context of Trr or mammalian COMPASS-like proteins deficient in H3K4 monomethylation activity and point to a possible role for H3K4me1 on cis-regulatory elements in specific settings to fine-tune transcriptional regulation in response to environmental stress.
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Affiliation(s)
- Ryan Rickels
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Hans-Martin Herz
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Christie C Sze
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Kaixiang Cao
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Marc A Morgan
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Clayton K Collings
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Maria Gause
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Yoh-Hei Takahashi
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lu Wang
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Emily J Rendleman
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Stacy A Marshall
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Annika Krueger
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Elizabeth T Bartom
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andrea Piunti
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Edwin R Smith
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nebiyu A Abshiru
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Neil L Kelleher
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Dale Dorsett
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Robert H. Lurie NCI Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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67
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Abstract
Polycomb Group (PcG) proteins epigenetically repress key developmental genes and thereby control alternative cell fates. PcG proteins act as complexes that can modify histones and these histone modifications play a role in transmitting the “memory” of the repressed state as cells divide. Here we consider mainstream models that link histone modifications to hierarchical recruitment of PcG complexes and compare them to results of a direct test of interdependence between PcG complexes for recruitment to Drosophila genes. The direct test indicates that PcG complexes do not rely on histone modifications to recognize their target genes but use them to stabilize the interactions within large chromatin domains. It also shows that multiple strategies are used to coordinate the targeting of PcG complexes to different genes, which may make the repression of these genes more or less robust.
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Affiliation(s)
- Eshagh Dorafshan
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Tatyana G Kahn
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
| | - Yuri B Schwartz
- a Department of Molecular Biology , Umeå University , Umeå , Sweden
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68
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Schuettengruber B, Bourbon HM, Di Croce L, Cavalli G. Genome Regulation by Polycomb and Trithorax: 70 Years and Counting. Cell 2017; 171:34-57. [DOI: 10.1016/j.cell.2017.08.002] [Citation(s) in RCA: 611] [Impact Index Per Article: 87.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/17/2017] [Accepted: 08/01/2017] [Indexed: 01/05/2023]
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69
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Sharma V, Kohli S, Brahmachari V. Correlation between desiccation stress response and epigenetic modifications of genes in Drosophila melanogaster: An example of environment-epigenome interaction. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:1058-1068. [PMID: 28801151 DOI: 10.1016/j.bbagrm.2017.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/05/2017] [Accepted: 08/05/2017] [Indexed: 01/12/2023]
Abstract
Animals from different phyla including arthropods tolerate water stress to different extent. This tolerance is accompanied by biochemical changes which in turn are due to transcriptional alteration. The changes in transcription can be an indirect effect on some of the genes, ensuing from the effect of stress on the regulators of transcription including epigenetic regulators. Within this paradigm, we investigated the correlation between stress response and epigenetic modification underlying gene expression modulation during desiccation stress in Canton-S. We report altered resistance of flies in desiccation stress for heterozygote mutants of PcG and TrxG members. Pc/+ mutant shows lower survival, while ash1/+ mutants show higher survival under desiccation stress as compared to Canton-S. We detect expression alteration in stress related genes as well the genes of the Polycomb and trithorax complex in Canton-S subjected to desiccation stress. Concomitant with this, there is an altered enrichment of H3K27me3 and H3K4me3 at the upstream regions of the stress responsive genes. The enrichment of activating mark, H3K4me3, is higher in non-stress condition. H3K27me3, the repressive mark, is more pronounced under stress condition, which in turn, can be correlated with the binding of Pc. Our results show that desiccation stress induces dynamic switching in expression and enrichment of PcG and TrxG in the upstream region of genes, which correlates with histone modifications. We provide evidence that epigenetic modulation could be one of the mechanisms to adapt to the desiccation stress in Drosophila. Thus, our study proposes the interaction of epigenome and environmental factors.
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Affiliation(s)
- Vineeta Sharma
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi 110 007, India.
| | - Surbhi Kohli
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi 110 007, India
| | - Vani Brahmachari
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, New Delhi 110 007, India
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70
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Kassis JA, Kennison JA, Tamkun JW. Polycomb and Trithorax Group Genes in Drosophila. Genetics 2017; 206:1699-1725. [PMID: 28778878 PMCID: PMC5560782 DOI: 10.1534/genetics.115.185116] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/15/2017] [Indexed: 01/08/2023] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) genes encode important regulators of development and differentiation in metazoans. These two groups of genes were discovered in Drosophila by their opposing effects on homeotic gene (Hox) expression. PcG genes collectively behave as genetic repressors of Hox genes, while the TrxG genes are necessary for HOX gene expression or function. Biochemical studies showed that many PcG proteins are present in two protein complexes, Polycomb repressive complexes 1 and 2, which repress transcription via chromatin modifications. TrxG proteins activate transcription via a variety of mechanisms. Here we summarize the large body of genetic and biochemical experiments in Drosophila on these two important groups of genes.
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Affiliation(s)
- Judith A Kassis
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - James A Kennison
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - John W Tamkun
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064
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71
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Chen M, Xie S, Ouyang Y, Yao J. Rice PcG gene OsEMF2b controls seed dormancy and seedling growth by regulating the expression of OsVP1. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 260:80-89. [PMID: 28554479 DOI: 10.1016/j.plantsci.2017.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 04/01/2017] [Accepted: 04/07/2017] [Indexed: 05/06/2023]
Abstract
The induction and release of seed dormancy are a precisely regulated process that influences seed germination. ABA promotes seed dormancy but suppresses seed germination and seedling growth. However, how chromatin and epigenetic mechanisms regulate the expression of ABA related genes during these processes remains unclear. Polycomb gene OsEMF2b was required for regulation of seed dormancy and seedling growth by dynamically activating and repressing ABA signal response genes. Downregulation of OsEMF2b led to vivipary and decreased expression level of OsVP1, which was involved in ABA signal pathway in seed dormancy. While, the seedlings with downregulation of OsEMF2b exhibited hyper-sensitive response to ABA and the expression of OsVP1 is upregulated. Yeast one-hybrid assay and ChIP analyses proved that OsEMF2b could bind to the promoter of OsVP1 directly and affected H3K27me3 enrichments of OsVP1 in seedling. Interestingly, both H3K27me3 and H3K4me3 enrichments of OsVP1 were changed with OsEMF2b mis-expression in seed and seedling. We proposed that OsEMF2b may play a pivotal role in seed dormancy and seedling growth by regulating the expression of OsVP1 indirectly or directly.
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Affiliation(s)
- Min Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shiyong Xie
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yidan Ouyang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China
| | - Jialing Yao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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72
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Morimoto M, Choi K, Boerkoel CF, Cho KS. Chromatin changes in SMARCAL1 deficiency: A hypothesis for the gene expression alterations of Schimke immuno-osseous dysplasia. Nucleus 2017; 7:560-571. [PMID: 27813696 DOI: 10.1080/19491034.2016.1255835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in SMARCAL1, which encodes a DNA annealing helicase with roles in DNA replication fork restart, DNA repair, and gene expression modulation, cause Schimke immuno-osseous dysplasia (SIOD), an autosomal recessive disease characterized by skeletal dysplasia, renal disease, T-cell immunodeficiency, and arteriosclerosis. The clinical features of SIOD arise from pathological changes in gene expression; however, the underlying mechanism for these gene expression alterations remains unclear. We hypothesized that changes of the epigenome alter gene expression in SIOD. To test this, we performed a genetic screen for interaction between Marcal1, the Drosophila melanogaster ortholog of SMARCAL1, and the genes of the trithorax group (trxG) and Polycomb group (PcG), which encode epigenetic regulators. SMARCAL1 and Marcal1 genetically interacted with trxG and PcG members. A homozygous null mutation of Marcal1 suppressed the wing-to-haltere transformation, ectopic Ultrabithorax (Ubx) expression, and ectopic Ubx minigene expression caused by PcG deficiency. The suppression of ectopic Ubx expression correlated with reduced chromatin accessibility of the Ubx promoter. To our knowledge, this is the first in vivo evidence for deficiency of a SMARCAL1 ortholog altering the chromatin structure of a gene.
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Affiliation(s)
- Marie Morimoto
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Kunho Choi
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Cornelius F Boerkoel
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Kyoung Sang Cho
- b Department of Biological Sciences , Konkuk University , Seoul , Republic of Korea
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73
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Coleman RT, Struhl G. Causal role for inheritance of H3K27me3 in maintaining the OFF state of a Drosophila HOX gene. Science 2017; 356:eaai8236. [PMID: 28302795 PMCID: PMC5595140 DOI: 10.1126/science.aai8236] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 02/03/2017] [Indexed: 12/20/2022]
Abstract
Many eukaryotic cells can respond to transient environmental or developmental stimuli with heritable changes in gene expression that are associated with nucleosome modifications. However, it remains uncertain whether modified nucleosomes play a causal role in transmitting such epigenetic memories, as opposed to controlling or merely reflecting transcriptional states inherited by other means. Here, we provide in vivo evidence that H3K27 trimethylated nucleosomes, once established at a repressed Drosophila HOX gene, remain heritably associated with that gene and can carry the memory of the silenced state through multiple rounds of replication, even when the capacity to copy the H3K27me3 mark to newly incorporated nucleosomes is diminished or abolished. Hence, in this context, the inheritance of H3K27 trimethylation conveys epigenetic memory.
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Affiliation(s)
- Rory T Coleman
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA
| | - Gary Struhl
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA.
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74
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Erceg J, Pakozdi T, Marco-Ferreres R, Ghavi-Helm Y, Girardot C, Bracken AP, Furlong EEM. Dual functionality of cis-regulatory elements as developmental enhancers and Polycomb response elements. Genes Dev 2017; 31:590-602. [PMID: 28381411 PMCID: PMC5393054 DOI: 10.1101/gad.292870.116] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/03/2017] [Indexed: 11/24/2022]
Abstract
Here, Erceg et al. studied the occupancy of the Drosophila PhoRC during embryogenesis and revealed extensive co-occupancy at developmental enhancers. By using an established in vivo assay for Polycomb response element (PRE) activity, they show that a subset of characterized developmental enhancers can function as PREs and silence transcription in a Polycomb-dependent manner, thereby suggesting that reuse of the same elements by the PcG system may help fine-tune gene expression and ensure the timely maintenance of cell identities. Developmental gene expression is tightly regulated through enhancer elements, which initiate dynamic spatio–temporal expression, and Polycomb response elements (PREs), which maintain stable gene silencing. These two cis-regulatory functions are thought to operate through distinct dedicated elements. By examining the occupancy of the Drosophila pleiohomeotic repressive complex (PhoRC) during embryogenesis, we revealed extensive co-occupancy at developmental enhancers. Using an established in vivo assay for PRE activity, we demonstrated that a subset of characterized developmental enhancers can function as PREs, silencing transcription in a Polycomb-dependent manner. Conversely, some classic Drosophila PREs can function as developmental enhancers in vivo, activating spatio–temporal expression. This study therefore uncovers elements with dual function: activating transcription in some cells (enhancers) while stably maintaining transcriptional silencing in others (PREs). Given that enhancers initiate spatio–temporal gene expression, reuse of the same elements by the Polycomb group (PcG) system may help fine-tune gene expression and ensure the timely maintenance of cell identities.
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Affiliation(s)
- Jelena Erceg
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Tibor Pakozdi
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Raquel Marco-Ferreres
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Yad Ghavi-Helm
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Charles Girardot
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Adrian P Bracken
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Eileen E M Furlong
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
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75
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Laprell F, Finkl K, Müller J. Propagation of Polycomb-repressed chromatin requires sequence-specific recruitment to DNA. Science 2017; 356:85-88. [DOI: 10.1126/science.aai8266] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 01/24/2017] [Indexed: 12/20/2022]
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76
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Chetverina DA, Elizar’ev PV, Lomaev DV, Georgiev PG, Erokhin MM. Control of the gene activity by polycomb and trithorax group proteins in Drosophila. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417020028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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77
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Mikulski P, Komarynets O, Fachinelli F, Weber AP, Schubert D. Characterization of the Polycomb-Group Mark H3K27me3 in Unicellular Algae. FRONTIERS IN PLANT SCIENCE 2017; 8:607. [PMID: 28484477 PMCID: PMC5405695 DOI: 10.3389/fpls.2017.00607] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 04/04/2017] [Indexed: 05/03/2023]
Abstract
Polycomb Group (PcG) proteins mediate chromatin repression in plants and animals by catalyzing H3K27 methylation and H2AK118/119 mono-ubiquitination through the activity of the Polycomb repressive complex 2 (PRC2) and PRC1, respectively. PcG proteins were extensively studied in higher plants, but their function and target genes in unicellular branches of the green lineage remain largely unknown. To shed light on PcG function and modus operandi in a broad evolutionary context, we demonstrate phylogenetic relationship of core PRC1 and PRC2 proteins and H3K27me3 biochemical presence in several unicellular algae of different phylogenetic subclades. We focus then on one of the species, the model red alga Cyanidioschizon merolae, and show that H3K27me3 occupies both, genes and repetitive elements, and mediates the strength of repression depending on the differential occupancy over gene bodies. Furthermore, we report that H3K27me3 in C. merolae is enriched in telomeric and subtelomeric regions of the chromosomes and has unique preferential binding toward intein-containing genes involved in protein splicing. Thus, our study gives important insight for Polycomb-mediated repression in lower eukaryotes, uncovering a previously unknown link between H3K27me3 targets and protein splicing.
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Affiliation(s)
- Pawel Mikulski
- Institute of Biology, Free University of BerlinBerlin, Germany
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Olga Komarynets
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
- Faculty of Medicine, University of GenevaGeneva, Switzerland
| | - Fabio Fachinelli
- Institute of Plant Biochemistry, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Andreas P.M. Weber
- Institute of Plant Biochemistry, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
| | - Daniel Schubert
- Institute of Biology, Free University of BerlinBerlin, Germany
- Institute of Genetics, Heinrich-Heine-Universität DüsseldorfDüsseldorf, Germany
- *Correspondence: Daniel Schubert,
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78
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Jung YL, Kang H, Park PJ, Kuroda MI. Correspondence of Drosophila polycomb group proteins with broad H3K27me3 silent domains. Fly (Austin) 2016; 9:178-82. [PMID: 26940990 DOI: 10.1080/19336934.2016.1151988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Youngsook L Jung
- a Department of Biomedical Informatics ; Harvard Medical School ; Boston , MA 02115
| | - Hyuckjoon Kang
- b Division of Genetics; Brigham and Women's Hospital ; Boston , MA 02115.,c Department of Genetics ; Harvard Medical School ; Boston , MA 02115
| | - Peter J Park
- a Department of Biomedical Informatics ; Harvard Medical School ; Boston , MA 02115
| | - Mitzi I Kuroda
- b Division of Genetics; Brigham and Women's Hospital ; Boston , MA 02115.,c Department of Genetics ; Harvard Medical School ; Boston , MA 02115
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79
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H3K27 methylation: a promiscuous repressive chromatin mark. Curr Opin Genet Dev 2016; 43:31-37. [PMID: 27940208 DOI: 10.1016/j.gde.2016.11.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022]
Abstract
Polycomb Repressive Complex 2 (PRC2) is a multiprotein complex that catalyzes the methylation of lysine 27 on histone H3 (H3K27me). This histone modification is a feature of facultative heterochromatin in many eukaryotes and maintains transcriptional repression established during early development. Understanding how PRC2 targets regions of the genome to be methylated remains poorly understood. Different cell types can show disparate patterns of H3K27me, and chromatin perturbations, such as loss of marks of constitutive heterochromatin, can cause redistribution of H3K27me, implying that DNA sequence, per se, is not sufficient to define the distribution of this mark. Emerging information supports the idea that the chromatin context-including histone modifications, DNA methylation, transcription, chromatin structure and organization within the nucleus-informs PRC2 target selection.
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80
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Koenecke N, Johnston J, He Q, Meier S, Zeitlinger J. Drosophila poised enhancers are generated during tissue patterning with the help of repression. Genome Res 2016; 27:64-74. [PMID: 27979994 PMCID: PMC5204345 DOI: 10.1101/gr.209486.116] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 11/08/2016] [Indexed: 12/18/2022]
Abstract
Histone modifications are frequently used as markers for enhancer states, but how to interpret enhancer states in the context of embryonic development is not clear. The poised enhancer signature, involving H3K4me1 and low levels of H3K27ac, has been reported to mark inactive enhancers that are poised for future activation. However, future activation is not always observed, and alternative reasons for the widespread occurrence of this enhancer signature have not been investigated. By analyzing enhancers during dorsal-ventral (DV) axis formation in the Drosophila embryo, we find that the poised enhancer signature is specifically generated during patterning in the tissue where the enhancers are not induced, including at enhancers that are known to be repressed by a transcriptional repressor. These results suggest that, rather than serving exclusively as an intermediate step before future activation, the poised enhancer state may be a mark for spatial regulation during tissue patterning. We discuss the possibility that the poised enhancer state is more generally the result of repression by transcriptional repressors.
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Affiliation(s)
- Nina Koenecke
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Jeff Johnston
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Qiye He
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Samuel Meier
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,University of Kansas Medical Center, Department of Pathology, Kansas City, Kansas 66160, USA
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81
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An Ash1-Like Protein MoKMT2H Null Mutant Is Delayed for Conidium Germination and Pathogenesis in Magnaporthe oryzae. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1575430. [PMID: 27747223 PMCID: PMC5056239 DOI: 10.1155/2016/1575430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 11/17/2022]
Abstract
Ash1 is a known H3K36-specific histone demethylase that is required for normal Hox gene expression and fertility in Drosophila and mammals. However, little is known about the expression and function of the fungal ortholog of Ash1 in phytopathogenic fungus Magnaporthe oryzae. Here we report that MoKMT2H, an Ash1-like protein, is required for conidium germination and virulence in rice. We obtained MoKMT2H null mutant (ΔMoKMT2H) using a target gene replacement strategy. In the ΔMoKMT2H null mutants, global histone methyltransferase modifications (H3K4me3, H3K9me3, H3K27me3, and H3K36me2/3) of the genome were unaffected. The ΔMoKMT2H mutants showed no defect in vegetative hyphal growth, conidium morphology, conidiation, or disease lesion formation on rice leaves. However, the MoKMT2H deletion mutants were delayed for conidium germination and consequently had decreased virulence. Taken together, our results indicated that MoKMT2H plays an important role in conidium germination during appressorium formation in the rice blast fungus and perhaps other pathogenic plant fungi.
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82
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Shlyueva D, Meireles-Filho ACA, Pagani M, Stark A. Genome-Wide Ultrabithorax Binding Analysis Reveals Highly Targeted Genomic Loci at Developmental Regulators and a Potential Connection to Polycomb-Mediated Regulation. PLoS One 2016; 11:e0161997. [PMID: 27575958 PMCID: PMC5004984 DOI: 10.1371/journal.pone.0161997] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 08/16/2016] [Indexed: 12/22/2022] Open
Abstract
Hox homeodomain transcription factors are key regulators of animal development. They specify the identity of segments along the anterior-posterior body axis in metazoans by controlling the expression of diverse downstream targets, including transcription factors and signaling pathway components. The Drosophila melanogaster Hox factor Ultrabithorax (Ubx) directs the development of thoracic and abdominal segments and appendages, and loss of Ubx function can lead for example to the transformation of third thoracic segment appendages (e.g. halters) into second thoracic segment appendages (e.g. wings), resulting in a characteristic four-wing phenotype. Here we present a Drosophila melanogaster strain with a V5-epitope tagged Ubx allele, which we employed to obtain a high quality genome-wide map of Ubx binding sites using ChIP-seq. We confirm the sensitivity of the V5 ChIP-seq by recovering 7/8 of well-studied Ubx-dependent cis-regulatory regions. Moreover, we show that Ubx binding is predictive of enhancer activity as suggested by comparison with a genome-scale resource of in vivo tested enhancer candidates. We observed densely clustered Ubx binding sites at 12 extended genomic loci that included ANTP-C, BX-C, Polycomb complex genes, and other regulators and the clustered binding sites were frequently active enhancers. Furthermore, Ubx binding was detected at known Polycomb response elements (PREs) and was associated with significant enrichments of Pc and Pho ChIP signals in contrast to binding sites of other developmental TFs. Together, our results show that Ubx targets developmental regulators via strongly clustered binding sites and allow us to hypothesize that regulation by Ubx might involve Polycomb group proteins to maintain specific regulatory states in cooperative or mutually exclusive fashion, an attractive model that combines two groups of proteins with prominent gene regulatory roles during animal development.
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Affiliation(s)
- Daria Shlyueva
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | | | - Michaela Pagani
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- * E-mail:
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83
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Kahn TG, Dorafshan E, Schultheis D, Zare A, Stenberg P, Reim I, Pirrotta V, Schwartz YB. Interdependence of PRC1 and PRC2 for recruitment to Polycomb Response Elements. Nucleic Acids Res 2016; 44:10132-10149. [PMID: 27557709 PMCID: PMC5137424 DOI: 10.1093/nar/gkw701] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 12/31/2022] Open
Abstract
Polycomb Group (PcG) proteins are epigenetic repressors essential for control of development and cell differentiation. They form multiple complexes of which PRC1 and PRC2 are evolutionary conserved and obligatory for repression. The targeting of PRC1 and PRC2 is poorly understood and was proposed to be hierarchical and involve tri-methylation of histone H3 (H3K27me3) and/or monoubiquitylation of histone H2A (H2AK118ub). Here, we present a strict test of this hypothesis using the Drosophila model. We discover that neither H3K27me3 nor H2AK118ub is required for targeting PRC complexes to Polycomb Response Elements (PREs). We find that PRC1 can bind PREs in the absence of PRC2 but at many PREs PRC2 requires PRC1 to be targeted. We show that one role of H3K27me3 is to allow PcG complexes anchored at PREs to interact with surrounding chromatin. In contrast, the bulk of H2AK118ub is unrelated to PcG repression. These findings radically change our view of how PcG repression is targeted and suggest that PRC1 and PRC2 can communicate independently of histone modifications.
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Affiliation(s)
- Tatyana G Kahn
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Eshagh Dorafshan
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Dorothea Schultheis
- Friedrich-Alexander University of Erlangen-Nürnberg, Department of Biology, Division of Developmental Biology, Erlangen, D-91058, Germany
| | - Aman Zare
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Per Stenberg
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden.,Division of CBRN Defense and Security, Swedish Defense Research Agency, FOI, Umeå, 906 21, Sweden
| | - Ingolf Reim
- Friedrich-Alexander University of Erlangen-Nürnberg, Department of Biology, Division of Developmental Biology, Erlangen, D-91058, Germany
| | - Vincenzo Pirrotta
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Yuri B Schwartz
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
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84
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Zhang J, Xie S, Cheng J, Lai J, Zhu JK, Gong Z. The Second Subunit of DNA Polymerase Delta Is Required for Genomic Stability and Epigenetic Regulation. PLANT PHYSIOLOGY 2016; 171:1192-208. [PMID: 27208288 PMCID: PMC4902588 DOI: 10.1104/pp.15.01976] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/24/2016] [Indexed: 05/08/2023]
Abstract
DNA polymerase δ plays crucial roles in DNA repair and replication as well as maintaining genomic stability. However, the function of POLD2, the second small subunit of DNA polymerase δ, has not been characterized yet in Arabidopsis (Arabidopsis thaliana). During a genetic screen for release of transcriptional gene silencing, we identified a mutation in POLD2. Whole-genome bisulfite sequencing indicated that POLD2 is not involved in the regulation of DNA methylation. POLD2 genetically interacts with Ataxia Telangiectasia-mutated and Rad3-related and DNA polymerase α The pold2-1 mutant exhibits genomic instability with a high frequency of homologous recombination. It also exhibits hypersensitivity to DNA-damaging reagents and short telomere length. Whole-genome chromatin immunoprecipitation sequencing and RNA sequencing analyses suggest that pold2-1 changes H3K27me3 and H3K4me3 modifications, and these changes are correlated with the gene expression levels. Our study suggests that POLD2 is required for maintaining genome integrity and properly establishing the epigenetic markers during DNA replication to modulate gene expression.
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Affiliation(s)
- Jixiang Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Shaojun Xie
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jinkui Cheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jinsheng Lai
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Jian-Kang Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China (J.Z., J.C., Z.G.);Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (S.X., J.-K.Z.);Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47906 (S.X., J.-K.Z.); andState Key Laboratory of Agrobiotechnology, China National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China (J.L.)
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85
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Warnefors M, Hartmann B, Thomsen S, Alonso CR. Combinatorial Gene Regulatory Functions Underlie Ultraconserved Elements in Drosophila. Mol Biol Evol 2016; 33:2294-306. [PMID: 27247329 PMCID: PMC4989106 DOI: 10.1093/molbev/msw101] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ultraconserved elements (UCEs) are discrete genomic elements conserved across large evolutionary distances. Although UCEs have been linked to multiple facets of mammalian gene regulation their extreme evolutionary conservation remains largely unexplained. Here, we apply a computational approach to investigate this question in Drosophila, exploring the molecular functions of more than 1,500 UCEs shared across the genomes of 12 Drosophila species. Our data indicate that Drosophila UCEs are hubs for gene regulatory functions and suggest that UCE sequence invariance originates from their combinatorial roles in gene control. We also note that the gene regulatory roles of intronic and intergenic UCEs (iUCEs) are distinct from those found in exonic UCEs (eUCEs). In iUCEs, transcription factor (TF) and epigenetic factor binding data strongly support iUCE roles in transcriptional and epigenetic regulation. In contrast, analyses of eUCEs indicate that they are two orders of magnitude more likely than the expected to simultaneously include protein-coding sequence, TF-binding sites, splice sites, and RNA editing sites but have reduced roles in transcriptional or epigenetic regulation. Furthermore, we use a Drosophila cell culture system and transgenic Drosophila embryos to validate the notion of UCE combinatorial regulatory roles using an eUCE within the Hox gene Ultrabithorax and show that its protein-coding region also contains alternative splicing regulatory information. Taken together our experiments indicate that UCEs emerge as a result of combinatorial gene regulatory roles and highlight common features in mammalian and insect UCEs implying that similar processes might underlie ultraconservation in diverse animal taxa.
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Affiliation(s)
- Maria Warnefors
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Britta Hartmann
- Institute of Human Genetics, Freiburg, Germany BIOSS Centre for Biological Signaling Studies, University Medical Center Freiburg, Freiburg, Germany
| | - Stefan Thomsen
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Claudio R Alonso
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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86
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The Polycomb group protein CLF emerges as a specific tri-methylase of H3K27 regulating gene expression and development in Physcomitrella patens. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:860-70. [PMID: 27179444 DOI: 10.1016/j.bbagrm.2016.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/14/2016] [Accepted: 05/05/2016] [Indexed: 01/29/2023]
Abstract
Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhancer of zeste (E(z)), a component of the PcG complex from Drosophila, one of which is a SET domain protein designated CURLY LEAF (CLF). Although this SET domain protein exhibits a strong correlation with the presence of the H3K27me3 mark in plants, the methyl-transferase activity and specificity of its SET domain have not been directly tested in-vivo. Using the evolutionary early-diverged land plant model species Physcomitrella patens we show that abolishment of a single copy gene PpCLF, as well as an additional member of the PcG complex, FERTILIZATION-INDEPENDENT ENDOSPERM (PpFIE), results in a specific loss of tri-methylation of H3K27. Using site-directed mutagenesis of key residues, we revealed that H3K27 tri-methylation is mediated by the SET domain of the CLF protein. Moreover, the abolishment of H3K27me3 led to enhanced expression of transcription factor genes. This in turn led to the development of fertilization-independent sporophyte-like structures, as observed in PpCLF and PpFIE null mutants. Overall, our results demonstrate the role of PpCLF as a SET protein in tri-methylation of H3K27 in-vivo and the importance of this modification in regulating the expression of transcription factor genes involved in developmental programs of P. patens.
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87
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A positive role for polycomb in transcriptional regulation via H4K20me1. Cell Res 2016; 26:529-42. [PMID: 27002220 PMCID: PMC4856762 DOI: 10.1038/cr.2016.33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 12/24/2022] Open
Abstract
The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc+H3K27me3+H4K20me1+ genes, but not in Pc+H3K27me3+H4K20me1− genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc+H3K27me3+H4K20me1+ genes in developing Drosophila wing disc.
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88
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Sadasivam DA, Huang DH. Maintenance of Tissue Pluripotency by Epigenetic Factors Acting at Multiple Levels. PLoS Genet 2016; 12:e1005897. [PMID: 26926299 PMCID: PMC4771708 DOI: 10.1371/journal.pgen.1005897] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/04/2016] [Indexed: 01/24/2023] Open
Abstract
Pluripotent stem cells often adopt a unique developmental program while retaining certain flexibility. The molecular basis of such properties remains unclear. Using differentiation of pluripotent Drosophila imaginal tissues as assays, we examined the contribution of epigenetic factors in ectopic activation of Hox genes. We found that over-expression of Trithorax H3K4 methyltransferase can induce ectopic adult appendages by selectively activating the Hox genes Ultrabithorax and Sex comb reduced in wing and leg discs, respectively. This tissue-specific inducibility correlates with the presence of paused RNA polymerase II in the promoter-proximal region of these genes. Although the Antennapedia promoter is paused in eye-antenna discs, it cannot be induced by Trx without a reduction in histone variants or their chaperones, suggesting additional control by the nucleosomal architecture. Lineage tracing and pulse-chase experiments revealed that the active state of Hox genes is maintained substantially longer in mutants deficient for HIRA, a chaperone for the H3.3 variant. In addition, both HIRA and H3.3 appeared to act cooperatively with the Polycomb group of epigenetic repressors. These results support the involvement of H3.3-mediated nucleosome turnover in restoring the repressed state. We propose a regulatory framework integrating transcriptional pausing, histone modification, nucleosome architecture and turnover for cell lineage maintenance. During animal development, the primordia of different body parts undergo a series of transitions in which their developmental potency becomes more restricted. Hox genes encode a family of evolutionarily conserved transcriptional factors that are crucial for choosing different paths during transitions. Thus, the transcriptional status of Hox genes is directly linked to the maintenance and developmental direction of pluripotent tissues. As post-translational methylation of histone H3 is pivotal for transcriptional control, we could activate Hox genes and alter the subsequent development of some pluripotent Drosophila imaginal tissues by increasing the level of Trithorax that catalyzes activation-related methylation. However, other imaginal tissues remain refractory unless histone variants or their chaperones that directly affect nucleosome dynamics are simultaneously depleted. By monitoring the duration of Hox expression under these conditions, we found that the active state of Hox genes is substantially prolonged, resulting from effective conversion of promoter-associated paused RNA polymerase II into active transcription. Further analyses indicate that these factors are functionally linked to the Polycomb group of epigenetic factors that bestow long-term repression. Our studies demonstrate that developmental constraints are modulated by factors acting at multiple levels, offering a useful approach to tissue re-programming in regeneration medicine and stem cell research.
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Affiliation(s)
- Devendran A. Sadasivam
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Der-Hwa Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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89
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Chi and dLMO function antagonistically on Notch signaling through directly regulation of fng transcription. Sci Rep 2016; 6:18937. [PMID: 26738424 PMCID: PMC4704065 DOI: 10.1038/srep18937] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/01/2015] [Indexed: 11/08/2022] Open
Abstract
Gene apterous (ap), chip (chi) and beadex (bx) play important roles in the dorsal-ventral compartmentalization in Drosophila wing discs. Meanwhile, Notch signaling is essential to the same process. It has been reported that Ap and Chi function as a tetramer to regulate Notch signaling. At the same time, dLMO (the protein product of gene bx) regulates the activity of Ap by competing its binding with Chi. However, the detailed functions of Chi and dLMO on Notch signaling and the relevant mechanisms remain largely unknown. Here, we report the detailed functions of Chi and dLMO on Notch signaling. Different Chi protein levels in adjacent cells could activate Notch signaling mainly in the cells with higher level of Chi. dLMO could induce antagonistical phenotypes on Notch signaling compared to that induced by Chi. These processes depend on their direct regulation of fringe (fng) transcription.
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90
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Elizar’ev PV, Lomaev DV, Chetverina DA, Georgiev PG, Erokhin MM. Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster. Acta Naturae 2016; 8:79-86. [PMID: 27446595 PMCID: PMC4954543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesn't prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.
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Affiliation(s)
- P. V. Elizar’ev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov str. 34/5, 119334, Moscow, Russia
| | - D. V. Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov str. 34/5, 119334, Moscow, Russia
| | - D. A. Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov str. 34/5, 119334, Moscow, Russia
| | - P. G. Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov str. 34/5, 119334, Moscow, Russia
| | - M. M. Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov str. 34/5, 119334, Moscow, Russia
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91
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Transcription through Polycomb response elements does not induce a switch from repression to activation. Proc Natl Acad Sci U S A 2015; 112:14755-6. [PMID: 26567151 DOI: 10.1073/pnas.1520102112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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92
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Transcriptional read-through is not sufficient to induce an epigenetic switch in the silencing activity of Polycomb response elements. Proc Natl Acad Sci U S A 2015; 112:14930-5. [PMID: 26504232 DOI: 10.1073/pnas.1515276112] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Drosophila, Polycomb (PcG) and Trithorax (TrxG) group proteins are assembled on Polycomb response elements (PREs) to maintain tissue and stage-specific patterns of gene expression. Critical to coordinating gene expression with the process of differentiation, the activity of PREs can be switched "on" and "off." When on, the PRE imposes a silenced state on the genes in the same domain that is stably inherited through multiple rounds of cell division. When the PRE is switched off, the domain is in a state permissive for gene expression that can be stably inherited. Previous studies have suggested that a burst of transcription through a PRE sequence displaces PcG proteins and provides a universal mechanism for inducing a heritable switch in PRE activity from on to off; however, the evidence favoring this model is indirect. Here, we have directly tested the transcriptional read-through mechanism. Contrary to previous suggestions, we show that transcription through the PRE is not sufficient for inducing an epigenetic switch in PRE activity. In fact, even high levels of continuous transcription through a PRE fails to dislodge the PcG proteins, nor does it remove repressive histone marks. Our results indicate that other mechanisms involving adjacent DNA regulatory elements must be implicated in heritable switch of PRE activity.
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93
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Brinkmeier ML, Geister KA, Jones M, Waqas M, Maillard I, Camper SA. The Histone Methyltransferase Gene Absent, Small, or Homeotic Discs-1 Like Is Required for Normal Hox Gene Expression and Fertility in Mice. Biol Reprod 2015; 93:121. [PMID: 26333994 DOI: 10.1095/biolreprod.115.131516] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/01/2015] [Indexed: 01/27/2023] Open
Abstract
Chromatin remodeling influences gene expression in developing and adult organisms. Active and repressive marks of histone methylation dictate the embryonic expression boundaries of developmentally regulated genes, including the Hox gene cluster. Drosophila ash1 (absent, small or homeotic discs 1) gene encodes a histone methyltransferase essential for regulation of Hox gene expression that interacts genetically with other members of the trithorax group (TrxG). While mammalian members of the mixed lineage leukemia (Mll) family of TrxG genes have roles in regulation of Hox gene expression, little is known about the expression and function of the mammalian ortholog of the Drosophila ash1 gene, Ash1-like (Ash1l). Here we report the expression of mouse Ash1l gene in specific structures within various organs and provide evidence that reduced Ash1l expression has tissue-specific effects on mammalian development and adult homeostasis. Mutants exhibit partially penetrant postnatal lethality and failure to thrive. Surviving mutants have growth insufficiency, skeletal transformations, and infertility associated with developmental defects in both male and female reproductive organs. Specifically, expression of Hoxa11 and Hoxd10 are altered in the epididymis of Ash1l mutant males and Hoxa10 is reduced in the uterus of Ash1l mutant females. In summary, we show that the histone methyltransferase Ash1l is important for the development and function of several tissues and for proper expression of homeotic genes in mammals.
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Affiliation(s)
| | - Krista A Geister
- Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan
| | - Morgan Jones
- Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan
| | - Meriam Waqas
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
| | - Ivan Maillard
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan Life Sciences Institute, University of Michigan, Ann Arbor, Michigan
| | - Sally A Camper
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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94
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Geisler SJ, Paro R. Trithorax and Polycomb group-dependent regulation: a tale of opposing activities. Development 2015; 142:2876-2887. [DOI: 10.1242/dev.120030] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Intricate layers of regulation determine the unique gene expression profiles of a given cell and, therefore, underlie the immense phenotypic diversity observed among cell types. Understanding the mechanisms that govern which genes are expressed and which genes are silenced is a fundamental focus in biology. The Polycomb and Trithorax group chromatin proteins play important roles promoting the stable and heritable repression and activation of gene expression, respectively. These proteins, which are conserved across metazoans, modulate post-translational modifications on histone tails and regulate nucleosomal structures. Here, we review recent advances that have shed light on the mechanisms by which these two classes of proteins act to maintain epigenetic memory and allow dynamic switches in gene expression during development.
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Affiliation(s)
- Sarah J. Geisler
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Renato Paro
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
- Faculty of Science, University of Basel, Klingelbergstrasse 50, Basel 4056, Switzerland
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95
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Maeda RK, Karch F. The open for business model of the bithorax complex in Drosophila. Chromosoma 2015; 124:293-307. [PMID: 26067031 PMCID: PMC4548009 DOI: 10.1007/s00412-015-0522-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/19/2015] [Accepted: 05/19/2015] [Indexed: 01/13/2023]
Abstract
After nearly 30 years of effort, Ed Lewis published his 1978 landmark paper in which he described the analysis of a series of mutations that affect the identity of the segments that form along the anterior-posterior (AP) axis of the fly (Lewis 1978). The mutations behaved in a non-canonical fashion in complementation tests, forming what Ed Lewis called a "pseudo-allelic" series. Because of this, he never thought that the mutations represented segment-specific genes. As all of these mutations were grouped to a particular area of the Drosophila third chromosome, the locus became known of as the bithorax complex (BX-C). One of the key findings of Lewis' article was that it revealed for the first time, to a wide scientific audience, that there was a remarkable correlation between the order of the segment-specific mutations along the chromosome and the order of the segments they affected along the AP axis. In Ed Lewis' eyes, the mutants he discovered affected "segment-specific functions" that were sequentially activated along the chromosome as one moves from anterior to posterior along the body axis (the colinearity concept now cited in elementary biology textbooks). The nature of the "segment-specific functions" started to become clear when the BX-C was cloned through the pioneering chromosomal walk initiated in the mid 1980s by the Hogness and Bender laboratories (Bender et al. 1983a; Karch et al. 1985). Through this molecular biology effort, and along with genetic characterizations performed by Gines Morata's group in Madrid (Sanchez-Herrero et al. 1985) and Robert Whittle's in Sussex (Tiong et al. 1985), it soon became clear that the whole BX-C encoded only three protein-coding genes (Ubx, abd-A, and Abd-B). Later, immunostaining against the Ubx protein hinted that the segment-specific functions could, in fact, be cis-regulatory elements regulating the expression of the three protein-coding genes. In 1987, Peifer, Karch, and Bender proposed a comprehensive model of the functioning of the BX-C, in which the "segment-specific functions" appear as segment-specific enhancers regulating, Ubx, abd-A, or Abd-B (Peifer et al. 1987). Key to their model was that the segmental address of these enhancers was not an inherent ability of the enhancers themselves, but was determined by the chromosomal location in which they lay. In their view, the sequential activation of the segment-specific functions resulted from the sequential opening of chromatin domains along the chromosome as one moves from anterior to posterior. This model soon became known of as the open for business model. While the open for business model is quite easy to visualize at a conceptual level, molecular evidence to validate this model has been missing for almost 30 years. The recent publication describing the outstanding, joint effort from the Bender and Kingston laboratories now provides the missing proof to support this model (Bowman et al. 2014). The purpose of this article is to review the open for business model and take the reader through the genetic arguments that led to its elaboration.
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Affiliation(s)
- Robert K. Maeda
- Department of Genetics and Evolution, University of Geneva, 30 quai E. Ansermet, 1211 Geneva-4, Switzerland
| | - François Karch
- Department of Genetics and Evolution, University of Geneva, 30 quai E. Ansermet, 1211 Geneva-4, Switzerland
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96
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Kang H, McElroy KA, Jung YL, Alekseyenko AA, Zee BM, Park PJ, Kuroda MI. Sex comb on midleg (Scm) is a functional link between PcG-repressive complexes in Drosophila. Genes Dev 2015; 29:1136-50. [PMID: 26063573 PMCID: PMC4470282 DOI: 10.1101/gad.260562.115] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this study, Kang et al. investigate how PcG complexes form repressive chromatin domains. The findings show that Scm, a transcriptional repressor, is an important regulator of PRC1, PRC2, and transcriptional silencing and suggest that Scm coordinates PcG complexes and polymerizes, resulting in PcG silencing. The Polycomb group (PcG) proteins are key regulators of development in Drosophila and are strongly implicated in human health and disease. How PcG complexes form repressive chromatin domains remains unclear. Using cross-linked affinity purifications of BioTAP-Polycomb (Pc) or BioTAP-Enhancer of zeste [E(z)], we captured all PcG-repressive complex 1 (PRC1) or PRC2 core components and Sex comb on midleg (Scm) as the only protein strongly enriched with both complexes. Although previously not linked to PRC2, we confirmed direct binding of Scm and PRC2 using recombinant protein expression and colocalization of Scm with PRC1, PRC2, and H3K27me3 in embryos and cultured cells using ChIP-seq (chromatin immunoprecipitation [ChIP] combined with deep sequencing). Furthermore, we found that RNAi knockdown of Scm and overexpression of the dominant-negative Scm-SAM (sterile α motif) domain both affected the binding pattern of E(z) on polytene chromosomes. Aberrant localization of the Scm-SAM domain in long contiguous regions on polytene chromosomes revealed its independent ability to spread on chromatin, consistent with its previously described ability to oligomerize in vitro. Pull-downs of BioTAP-Scm captured PRC1 and PRC2 and additional repressive complexes, including PhoRC, LINT, and CtBP. We propose that Scm is a key mediator connecting PRC1, PRC2, and transcriptional silencing. Combined with previous structural and genetic analyses, our results strongly suggest that Scm coordinates PcG complexes and polymerizes to produce broad domains of PcG silencing.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kyle A McElroy
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Youngsook Lucy Jung
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Artyom A Alekseyenko
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Barry M Zee
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA;
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97
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Morris-Rosendahl DJ, Kaindl AM. What next-generation sequencing (NGS) technology has enabled us to learn about primary autosomal recessive microcephaly (MCPH). Mol Cell Probes 2015; 29:271-81. [PMID: 26050940 DOI: 10.1016/j.mcp.2015.05.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 11/27/2022]
Abstract
The impact that next-generation sequencing technology (NGS) is having on many aspects of molecular and cell biology, is becoming increasingly apparent. One of the most noticeable outcomes of the new technology in human genetics, has been the accelerated rate of identification of disease-causing genes. Especially for rare, heterogeneous disorders, such as autosomal recessive primary microcephaly (MCPH), the handful of genes previously known to harbour disease-causing mutations, has grown at an unprecedented rate within a few years. Knowledge of new genes mutated in MCPH over the last four years has contributed to our understanding of the disorder at both the clinical and cellular levels. The functions of proteins such as WDR62, CASC5, PHC1, CDK6, CENP-E, CENP-F, CEP63, ZNF335, PLK4 and TUBGPC, have been added to the complex network of critical cellular processes known to be involved in brain growth and size. In addition to the importance of mitotic spindle assembly and structure, centrosome and centriole function and DNA repair and damage response, new mechanisms involving kinetochore-associated proteins and chromatin remodelling complexes have been elucidated. Two of the major contributions to our clinical knowledge are the realisation that primary microcephaly caused by mutations in genes at the MCPH loci is seldom an isolated clinical feature and is often accompanied either by additional cortical malformations or primordial dwarfism. Gene-phenotype correlations are being revisited, with a new dimension of locus heterogeneity and phenotypic variability being revealed.
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Affiliation(s)
- Deborah J Morris-Rosendahl
- Clinical Genetics and Genomics, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom; National Heart and Lung Institute, Imperial College London, London, United Kingdom.
| | - Angela M Kaindl
- Department of Pediatric Neurology, Charité University Medicine, Berlin, Germany; Institute of Cell Biology and Neurobiology, Charité University Medicine, Berlin, Germany
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98
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Borsos BN, Pankotai T, Kovács D, Popescu C, Páhi Z, Boros IM. Acetylations of Ftz-F1 and histone H4K5 are required for the fine-tuning of ecdysone biosynthesis during Drosophila metamorphosis. Dev Biol 2015; 404:80-7. [PMID: 25959239 DOI: 10.1016/j.ydbio.2015.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 04/14/2015] [Accepted: 04/24/2015] [Indexed: 11/18/2022]
Abstract
The molting during Drosophila development is tightly regulated by the ecdysone hormone. Several steps of the ecdysone biosynthesis have been already identified but the regulation of the entire process has not been clarified yet. We have previously reported that dATAC histone acetyltransferase complex is necessary for the steroid hormone biosynthesis process. To reveal possible mechanisms controlled by dATAC we made assumptions that either dATAC may influence directly the transcription of Halloween genes involved in steroid hormone biosynthesis or it may exert an indirect effect on it by acetylating the Ftz-F1 transcription factor which regulates the transcription of steroid converting genes. Here we show that the lack of dATAC complex results in increased mRNA level and decreased protein level of Ftz-F1. In this context, decreased mRNA and increased protein levels of Ftz-F1 were detected upon treatment of Drosophila S2 cells with histone deacetylase inhibitor trichostatin A. We showed that Ftz-F1, the transcriptional activator of Halloween genes, is acetylated in S2 cells. In addition, we found that ecdysone biosynthetic Halloween genes are transcribed in S2 cells and their expression can be influenced by deacetylase inhibitors. Furthermore, we could detect H4K5 acetylation at the regulatory regions of disembodied and shade Halloween genes, while H3K9 acetylation is absent on these genes. Based on our findings we conclude that the dATAC HAT complex might play a dual regulatory role in Drosophila steroid hormone biosynthesis through the acetylation of Ftz-F1 protein and the regulation of the H4K5 acetylation at the promoters of Halloween genes.
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Affiliation(s)
- Barbara N Borsos
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary
| | - Tibor Pankotai
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary; Institute of Biochemistry, Biological Research Center, Szeged, Hungary.
| | - Dávid Kovács
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary
| | - Christina Popescu
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary
| | - Zoltán Páhi
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary
| | - Imre M Boros
- Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary; Institute of Biochemistry, Biological Research Center, Szeged, Hungary
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99
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100
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Zhang Y, Laumet G, Chen SR, Hittelman WN, Pan HL. Pannexin-1 Up-regulation in the Dorsal Root Ganglion Contributes to Neuropathic Pain Development. J Biol Chem 2015; 290:14647-55. [PMID: 25925949 DOI: 10.1074/jbc.m115.650218] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Indexed: 01/10/2023] Open
Abstract
Pannexin-1 (Panx1) is a large-pore membrane channel involved in the release of ATP and other signaling mediators. Little is known about the expression and functional role of Panx1 in the dorsal root ganglion (DRG) in the development of chronic neuropathic pain. In this study, we determined the epigenetic mechanism involved in increased Panx1 expression in the DRG after nerve injury. Spinal nerve ligation in rats significantly increased the mRNA and protein levels of Panx1 in the DRG but not in the spinal cord. Immunocytochemical labeling showed that Panx1 was primarily expressed in a subset of medium and large DRG neurons in control rats and that nerve injury markedly increased the number of Panx1-immunoreactive DRG neurons. Nerve injury significantly increased the enrichment of two activating histone marks (H3K4me2 and H3K9ac) and decreased the occupancy of two repressive histone marks (H3K9me2 and H3K27me3) around the promoter region of Panx1 in the DRG. However, nerve injury had no effect on the DNA methylation level around the Panx1 promoter in the DRG. Furthermore, intrathecal injection of the Panx1 blockers or Panx1-specific siRNA significantly reduced pain hypersensitivity induced by nerve injury. In addition, siRNA knockdown of Panx1 expression in a DRG cell line significantly reduced caspase-1 release induced by neuronal depolarization. Our findings suggest that nerve injury increases Panx1 expression levels in the DRG through altered histone modifications. Panx1 up-regulation contributes to the development of neuropathic pain and stimulation of inflammasome signaling.
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Affiliation(s)
- Yuhao Zhang
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine and
| | - Geoffroy Laumet
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine and
| | - Shao-Rui Chen
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine and
| | - Walter N Hittelman
- Department of Experimental Therapeutics, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Hui-Lin Pan
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine and
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