1
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Liu J, Fan H, Liang X, Chen Y. Polycomb repressor complex: Its function in human cancer and therapeutic target strategy. Biomed Pharmacother 2023; 169:115897. [PMID: 37981459 DOI: 10.1016/j.biopha.2023.115897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
The Polycomb Repressor Complex (PRC) plays a pivotal role in gene regulation during development and disease, with dysregulation contributing significantly to various human cancers. The intricate interplay between PRC and cellular signaling pathways sheds light on cancer complexity. PRC presents promising therapeutic opportunities, with inhibitors undergoing rigorous evaluation in preclinical and clinical studies. In this review, we emphasize the critical role of PRC complex in gene regulation, particularly PcG proteins mediated chromatin compaction through phase separation. We also highlight the pathological implications of PRC complex dysregulation in various tumors, elucidating underlying mechanisms driving cancer progression. The burgeoning field of therapeutic strategies targeting PRC complexes, notably EZH2 inhibitors, has advanced significantly. However, we explore the need for combination therapies to enhance PRC targeted treatments efficacy, providing a glimpse into the future of cancer therapeutics.
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Affiliation(s)
- Jingrong Liu
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Hongjie Fan
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Xinmiao Liang
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yang Chen
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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2
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Erokhin M, Mogila V, Lomaev D, Chetverina D. Polycomb Recruiters Inside and Outside of the Repressed Domains. Int J Mol Sci 2023; 24:11394. [PMID: 37511153 PMCID: PMC10379775 DOI: 10.3390/ijms241411394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/24/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
The establishment and stable inheritance of individual patterns of gene expression in different cell types are required for the development of multicellular organisms. The important epigenetic regulators are the Polycomb group (PcG) and Trithorax group (TrxG) proteins, which control the silenced and active states of genes, respectively. In Drosophila, the PcG/TrxG group proteins are recruited to the DNA regulatory sequences termed the Polycomb response elements (PREs). The PREs are composed of the binding sites for different DNA-binding proteins, the so-called PcG recruiters. Currently, the role of the PcG recruiters in the targeting of the PcG proteins to PREs is well documented. However, there are examples where the PcG recruiters are also implicated in the active transcription and in the TrxG function. In addition, there is increasing evidence that the genome-wide PcG recruiters interact with the chromatin outside of the PREs and overlap with the proteins of differing regulatory classes. Recent studies of the interactomes of the PcG recruiters significantly expanded our understanding that they have numerous interactors besides the PcG proteins and that their functions extend beyond the regulation of the PRE repressive activity. Here, we summarize current data about the functions of the PcG recruiters.
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Affiliation(s)
- Maksim Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Vladic Mogila
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Dmitry Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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3
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Fedorova S, Dorogova NV, Karagodin DA, Oshchepkov DY, Brusentsov II, Klimova NV, Baricheva EM. The complex role of transcription factor GAGA in germline death during Drosophila spermatogenesis: transcriptomic and bioinformatic analyses. PeerJ 2023; 11:e14063. [PMID: 36643636 PMCID: PMC9835689 DOI: 10.7717/peerj.14063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 08/26/2022] [Indexed: 01/11/2023] Open
Abstract
The GAGA protein (also known as GAF) is a transcription factor encoded by the Trl gene in D. melanogaster. GAGA is involved in the regulation of transcription of many genes at all stages of fly development and life. Recently, we investigated the participation of GAGA in spermatogenesis and discovered that Trl mutants experience massive degradation of germline cells in the testes. Trl underexpression induces autophagic death of spermatocytes, thereby leading to reduced testis size. Here, we aimed to determine the role of the transcription factor GAGA in the regulation of ectopic germline cell death. We investigated how Trl underexpression affects gene expression in the testes. We identified 15,993 genes in three biological replicates of our RNA-seq analysis and compared transcript levels between hypomorphic Trl R85/Trl 362 and Oregon testes. A total of 2,437 differentially expressed genes were found, including 1,686 upregulated and 751 downregulated genes. At the transcriptional level, we detected the development of cellular stress in the Trl-mutant testes: downregulation of the genes normally expressed in the testes (indicating slowed or abrogated spermatocyte differentiation) and increased expression of metabolic and proteolysis-related genes, including stress response long noncoding RNAs. Nonetheless, in the Flybase Gene Ontology lists of genes related to cell death, autophagy, or stress, there was no enrichment with GAGA-binding sites. Furthermore, we did not identify any specific GAGA-dependent cell death pathway that could regulate spermatocyte death. Thus, our data suggest that GAGA deficiency in male germline cells leads to an imbalance of metabolic processes, impaired mitochondrial function, and cell death due to cellular stress.
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Affiliation(s)
- Svetlana Fedorova
- Department of Cell Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Natalya V. Dorogova
- Department of Cell Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Dmitriy A. Karagodin
- Department of Cell Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Dmitry Yu Oshchepkov
- Department of Systems Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Ilya I. Brusentsov
- Department of Cell Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Natalya V. Klimova
- Department of Molecular Genetics, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
| | - Elina M. Baricheva
- Department of Cell Biology, Institute of Cytology and Genetics SB RAS, Novosibirsk, Russian Federation
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4
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Chetverina D, Vorobyeva NE, Mazina MY, Fab LV, Lomaev D, Golovnina A, Mogila V, Georgiev P, Ziganshin RH, Erokhin M. Comparative interactome analysis of the PRE DNA-binding factors: purification of the Combgap-, Zeste-, Psq-, and Adf1-associated proteins. Cell Mol Life Sci 2022; 79:353. [PMID: 35676368 PMCID: PMC11072172 DOI: 10.1007/s00018-022-04383-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/14/2022] [Accepted: 05/08/2022] [Indexed: 01/08/2023]
Abstract
The Polycomb group (PcG) and Trithorax group (TrxG) proteins are key epigenetic regulators controlling the silenced and active states of genes in multicellular organisms, respectively. In Drosophila, PcG/TrxG proteins are recruited to the chromatin via binding to specific DNA sequences termed polycomb response elements (PREs). While precise mechanisms of the PcG/TrxG protein recruitment remain unknown, the important role is suggested to belong to sequence-specific DNA-binding factors. At the same time, it was demonstrated that the PRE DNA-binding proteins are not exclusively localized to PREs but can bind other DNA regulatory elements, including enhancers, promoters, and boundaries. To gain an insight into the PRE DNA-binding protein regulatory network, here, using ChIP-seq and immuno-affinity purification coupled to the high-throughput mass spectrometry, we searched for differences in abundance of the Combgap, Zeste, Psq, and Adf1 PRE DNA-binding proteins. While there were no conspicuous differences in co-localization of these proteins with other functional transcription factors, we show that Combgap and Zeste are more tightly associated with the Polycomb repressive complex 1 (PRC1), while Psq interacts strongly with the TrxG proteins, including the BAP SWI/SNF complex. The Adf1 interactome contained Mediator subunits as the top interactors. In addition, Combgap efficiently interacted with AGO2, NELF, and TFIID. Combgap, Psq, and Adf1 have architectural proteins in their networks. We further investigated the existence of direct interactions between different PRE DNA-binding proteins and demonstrated that Combgap-Adf1, Psq-Dsp1, and Pho-Spps can interact in the yeast two-hybrid assay. Overall, our data suggest that Combgap, Psq, Zeste, and Adf1 are associated with the protein complexes implicated in different regulatory activities and indicate their potential multifunctional role in the regulation of transcription.
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Affiliation(s)
- Darya Chetverina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia.
| | - Nadezhda E Vorobyeva
- Group of Dynamics of Transcriptional Complexes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Marina Yu Mazina
- Group of Hormone-Dependent Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Lika V Fab
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Dmitry Lomaev
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Alexandra Golovnina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Vladic Mogila
- Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Pavel Georgiev
- Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Maksim Erokhin
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia.
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5
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Liaw GJ. Polycomb repressive complex 1 initiates and maintains tailless repression in Drosophila embryo. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194786. [PMID: 35032681 DOI: 10.1016/j.bbagrm.2022.194786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/29/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Maternally-deposited morphogens specify the fates of embryonic cells via hierarchically regulating the expression of zygotic genes that encode various classes of developmental regulators. Once the cell fates are determined, Polycomb-group proteins frequently maintain the repressed state of the genes. This study investigates how Polycomb-group proteins repress the expression of tailless, which encodes a developmental regulator in Drosophila embryo. Previous studies have shown that maternal Tramtrack69 facilitates maternal GAGA-binding factor and Heat shock factor binding to the torso response element (tor-RE) to initiate tailless repression in the stage-4 embryo. Chromatin-immunoprecipitation and genetic-interaction studies exhibit that maternally-deposited Polycomb repressive complex 1 (PRC1) recruited by the tor-RE-associated Tramtrack69 represses tailless expression in the stage-4 embryo. A noncanonical Polycomb-group response element (PRE) is mapped to the tailless proximal region. High levels of Bric-a-brac, Tramtrack, and Broad (BTB)-domain proteins are fundamental for maintaining tailless repression in the stage-8 to -10 embryos. Trmtrack69 sporadically distributes in the linear BTB-domain oligomer, which recruits and retains a high level of PRC1 near the GCCAT cluster for repressing tll expression in the stage-14 embryos. Disrupting the retention of PRC1 decreases the levels of PRC1 and Pleiohomeotic protein substantially on the PRE and causes tailless derepression in the stage-14 embryo. Furthermore, the retained PRC1 potentially serves as a second foundation for assembling the well-characterized polymer of the Sterile alpha motif domain in Polyhomeotic protein, which compacts chromatin to maintain the repressed state of tailless in the embryos after stage 14.
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Affiliation(s)
- Gwo-Jen Liaw
- Department of Life Sciences and Institute of Genomic Sciences, National Yang Ming Chiao Tung University, Yangming Campus, No. 155, Sec. 2, Linong St., Taipei 112, Taiwan.
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6
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DeAngelis MW, Coolon JD, Johnson RI. Comparative transcriptome analyses of the Drosophila pupal eye. G3-GENES GENOMES GENETICS 2021; 11:5995320. [PMID: 33561221 PMCID: PMC8043229 DOI: 10.1093/g3journal/jkaa003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/08/2020] [Indexed: 12/04/2022]
Abstract
Tissue function is dependent on correct cellular organization and behavior. As a result, the identification and study of genes that contribute to tissue morphogenesis is of paramount importance to the fields of cell and developmental biology. Many of the genes required for tissue patterning and organization are highly conserved between phyla. This has led to the emergence of several model organisms and developmental systems that are used to study tissue morphogenesis. One such model is the Drosophila melanogaster pupal eye that has a highly stereotyped arrangement of cells. In addition, the pupal eye is postmitotic that allows for the study of tissue morphogenesis independent from any effects of proliferation. While the changes in cell morphology and organization that occur throughout pupal eye development are well documented, less is known about the corresponding transcriptional changes that choreograph these processes. To identify these transcriptional changes, we dissected wild-type Canton S pupal eyes and performed RNA-sequencing. Our analyses identified differential expression of many loci that are documented regulators of pupal eye morphogenesis and contribute to multiple biological processes including signaling, axon projection, adhesion, and cell survival. We also identified differential expression of genes not previously implicated in pupal eye morphogenesis such as components of the Toll pathway, several non-classical cadherins, and components of the muscle sarcomere, which could suggest these loci function as novel patterning factors.
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Affiliation(s)
- Miles W DeAngelis
- Department of Biology, Wesleyan University, 52 Lawn Avenue, Middletown, CT 06459, USA
| | - Joseph D Coolon
- Department of Biology, Wesleyan University, 52 Lawn Avenue, Middletown, CT 06459, USA
| | - Ruth I Johnson
- Department of Biology, Wesleyan University, 52 Lawn Avenue, Middletown, CT 06459, USA
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7
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Polycomb group-mediated histone H2A monoubiquitination in epigenome regulation and nuclear processes. Nat Commun 2020; 11:5947. [PMID: 33230107 PMCID: PMC7683540 DOI: 10.1038/s41467-020-19722-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 10/12/2020] [Indexed: 12/19/2022] Open
Abstract
Histone posttranslational modifications are key regulators of chromatin-associated processes including gene expression, DNA replication and DNA repair. Monoubiquitinated histone H2A, H2Aub (K118 in Drosophila or K119 in vertebrates) is catalyzed by the Polycomb group (PcG) repressive complex 1 (PRC1) and reversed by the PcG-repressive deubiquitinase (PR-DUB)/BAP1 complex. Here we critically assess the current knowledge regarding H2Aub deposition and removal, its crosstalk with PcG repressive complex 2 (PRC2)-mediated histone H3K27 methylation, and the recent attempts toward discovering its readers and solving its enigmatic functions. We also discuss mounting evidence of the involvement of H2A ubiquitination in human pathologies including cancer, while highlighting some knowledge gaps that remain to be addressed. Histone H2A monoubiquitination on lysine 119 in vertebrate and lysine 118 in Drosophila (H2Aub) is an epigenomic mark usually associated with gene repression by Polycomb group factors. Here the authors review the current knowledge on the deposition and removal of H2Aub, its function in transcription and other DNA-associated processes as well as its relevance to human disease.
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8
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Das P, Bhadra MP. Histone deacetylase (Rpd3) regulates Drosophila early brain development via regulation of Tailless. Open Biol 2020; 10:200029. [PMID: 32873153 PMCID: PMC7536075 DOI: 10.1098/rsob.200029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/29/2020] [Indexed: 11/29/2022] Open
Abstract
Tailless is a committed transcriptional repressor and principal regulator of the brain and eye development in Drosophila. Rpd3, the histone deacetylase, is an established repressor that interacts with co-repressors like Sin3a, Prospero, Brakeless and Atrophin. This study aims at deciphering the role of Rpd3 in embryonic segmentation and larval brain development in Drosophila. It delineates the mechanism of Tailless regulation by Rpd3, along with its interacting partners. There was a significant reduction in Tailless in Rpd3 heteroallelic mutant embryos, substantiating that Rpd3 is indispensable for the normal Tailless expression. The expression of the primary readout, Tailless was correlative to the expression of the neural cell adhesion molecule homologue, Fascilin2 (Fas2). Rpd3 also aids in the proper development of the mushroom body. Both Tailless and Fas2 expression are reported to be antagonistic to the epidermal growth factor receptor (EGFR) expression. The decrease in Tailless and Fas2 expression highlights that EGFR is upregulated in the larval mutants, hindering brain development. This study outlines the axis comprising Rpd3, dEGFR, Tailless and Fas2, which interact to fine-tune the early segmentation and larval brain development. Therefore, Rpd3 along with Tailless has immense significance in early embryogenesis and development of the larval brain.
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Affiliation(s)
- Paromita Das
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research (AcSIR) Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai 600 113, India
| | - Manika Pal Bhadra
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research (AcSIR) Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai 600 113, India
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9
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Boyle S, Flyamer IM, Williamson I, Sengupta D, Bickmore WA, Illingworth RS. A central role for canonical PRC1 in shaping the 3D nuclear landscape. Genes Dev 2020; 34:931-949. [PMID: 32439634 PMCID: PMC7328521 DOI: 10.1101/gad.336487.120] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/13/2020] [Indexed: 02/04/2023]
Abstract
In this study from Boyle et al., the authors investigated the role of Polycomb-repressive complex 1 (PRC1) in shaping 3D genome organization in mouse embryonic stem cells. Using a combination of imaging and Hi-C analyses they show that PRC1-mediated long-range interactions are independent of CTCF and can bridge sites at a megabase scale, thus providing novel insights into the function of PRC1. Polycomb group (PcG) proteins silence gene expression by chemically and physically modifying chromatin. A subset of PcG target loci are compacted and cluster in the nucleus; a conformation that is thought to contribute to gene silencing. However, how these interactions influence gross nuclear organization and their relationship with transcription remains poorly understood. Here we examine the role of Polycomb-repressive complex 1 (PRC1) in shaping 3D genome organization in mouse embryonic stem cells (mESCs). Using a combination of imaging and Hi-C analyses, we show that PRC1-mediated long-range interactions are independent of CTCF and can bridge sites at a megabase scale. Impairment of PRC1 enzymatic activity does not directly disrupt these interactions. We demonstrate that PcG targets coalesce in vivo, and that developmentally induced expression of one of the target loci disrupts this spatial arrangement. Finally, we show that transcriptional activation and the loss of PRC1-mediated interactions are separable events. These findings provide important insights into the function of PRC1, while highlighting the complexity of this regulatory system.
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Affiliation(s)
- Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Ilya M Flyamer
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Dipta Sengupta
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
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10
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Fursova NA, Blackledge NP, Nakayama M, Ito S, Koseki Y, Farcas AM, King HW, Koseki H, Klose RJ. Synergy between Variant PRC1 Complexes Defines Polycomb-Mediated Gene Repression. Mol Cell 2019; 74:1020-1036.e8. [PMID: 31029541 PMCID: PMC6561741 DOI: 10.1016/j.molcel.2019.03.024] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/04/2019] [Accepted: 03/21/2019] [Indexed: 01/30/2023]
Abstract
The Polycomb system modifies chromatin and plays an essential role in repressing gene expression to control normal mammalian development. However, the components and mechanisms that define how Polycomb protein complexes achieve this remain enigmatic. Here, we use combinatorial genetic perturbation coupled with quantitative genomics to discover the central determinants of Polycomb-mediated gene repression in mouse embryonic stem cells. We demonstrate that canonical Polycomb repressive complex 1 (PRC1), which mediates higher-order chromatin structures, contributes little to gene repression. Instead, we uncover an unexpectedly high degree of synergy between variant PRC1 complexes, which is fundamental to gene repression. We further demonstrate that variant PRC1 complexes are responsible for distinct pools of H2A monoubiquitylation that are associated with repression of Polycomb target genes and silencing during X chromosome inactivation. Together, these discoveries reveal a new variant PRC1-dependent logic for Polycomb-mediated gene repression.
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Affiliation(s)
- Nadezda A Fursova
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Neil P Blackledge
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Manabu Nakayama
- Laboratory of Medical Omics Research, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan
| | - Shinsuke Ito
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Yoko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Anca M Farcas
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Hamish W King
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Haruhiko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan; AMED-CREST, Japanese Agency for Medical Research and Development, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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11
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Domsch K, Carnesecchi J, Disela V, Friedrich J, Trost N, Ermakova O, Polychronidou M, Lohmann I. The Hox transcription factor Ubx stabilizes lineage commitment by suppressing cellular plasticity in Drosophila. eLife 2019; 8:42675. [PMID: 31050646 PMCID: PMC6513553 DOI: 10.7554/elife.42675] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 04/30/2019] [Indexed: 12/22/2022] Open
Abstract
During development cells become restricted in their differentiation potential by repressing alternative cell fates, and the Polycomb complex plays a crucial role in this process. However, how alternative fate genes are lineage-specifically silenced is unclear. We studied Ultrabithorax (Ubx), a multi-lineage transcription factor of the Hox class, in two tissue lineages using sorted nuclei and interfered with Ubx in mesodermal cells. We find that depletion of Ubx leads to the de-repression of genes normally expressed in other lineages. Ubx silences expression of alternative fate genes by retaining the Polycomb Group protein Pleiohomeotic at Ubx targeted genomic regions, thereby stabilizing repressive chromatin marks in a lineage-dependent manner. Our study demonstrates that Ubx stabilizes lineage choice by suppressing the multipotency encoded in the genome via its interaction with Pho. This mechanism may explain why the Hox code is maintained throughout the lifecycle, since it could set a block to transdifferentiation in adult cells.
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Affiliation(s)
- Katrin Domsch
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
| | | | - Vanessa Disela
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
| | - Jana Friedrich
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
| | - Nils Trost
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
| | - Olga Ermakova
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
| | | | - Ingrid Lohmann
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg, Germany
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12
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Alhaj Abed J, Ghotbi E, Ye P, Frolov A, Benes J, Jones RS. De novo recruitment of Polycomb-group proteins in Drosophila embryos. Development 2018; 145:dev.165027. [PMID: 30389849 DOI: 10.1242/dev.165027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 10/29/2018] [Indexed: 12/24/2022]
Abstract
Polycomb-group (PcG)-mediated transcriptional repression of target genes can be delineated into two phases. First, following initial repression of target genes by gene-specific transcription factors, PcG proteins recognize the repressed state and assume control of the genes' repression. Second, once the silenced state is established, PcG proteins may maintain repression through an indefinite number of cell cycles. Little is understood about how PcG proteins initially recognize the repressed state of target genes and the steps leading to de novo establishment of PcG-mediated repression. We describe a genetic system in which a Drosophila PcG target gene, giant (gt), is ubiquitously repressed during early embryogenesis by a maternally expressed transcription factor, and show the temporal recruitment of components of three PcG protein complexes: PhoRC, PRC1 and PRC2. We show that de novo PcG recruitment follows a temporal hierarchy in which PhoRC stably localizes at the target gene at least 1 h before stable recruitment of PRC2 and concurrent trimethylation of histone H3 at lysine 27 (H3K27me3). The presence of PRC2 and increased levels of H3K27me3 are found to precede stable binding by PRC1.
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Affiliation(s)
- Jumana Alhaj Abed
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Elnaz Ghotbi
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Piao Ye
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Alexander Frolov
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Judith Benes
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | - Richard S Jones
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
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13
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From Flies to Mice: The Emerging Role of Non-Canonical PRC1 Members in Mammalian Development. EPIGENOMES 2018. [DOI: 10.3390/epigenomes2010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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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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Yeung K, Boija A, Karlsson E, Holmqvist PH, Tsatskis Y, Nisoli I, Yap D, Lorzadeh A, Moksa M, Hirst M, Aparicio S, Fanto M, Stenberg P, Mannervik M, McNeill H. Atrophin controls developmental signaling pathways via interactions with Trithorax-like. eLife 2017; 6:e23084. [PMID: 28327288 PMCID: PMC5409829 DOI: 10.7554/elife.23084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/15/2017] [Indexed: 12/30/2022] Open
Abstract
Mutations in human Atrophin1, a transcriptional corepressor, cause dentatorubral-pallidoluysian atrophy, a neurodegenerative disease. Drosophila Atrophin (Atro) mutants display many phenotypes, including neurodegeneration, segmentation, patterning and planar polarity defects. Despite Atro's critical role in development and disease, relatively little is known about Atro's binding partners and downstream targets. We present the first genomic analysis of Atro using ChIP-seq against endogenous Atro. ChIP-seq identified 1300 potential direct targets of Atro including engrailed, and components of the Dpp and Notch signaling pathways. We show that Atro regulates Dpp and Notch signaling in larval imaginal discs, at least partially via regulation of thickveins and fringe. In addition, bioinformatics analyses, sequential ChIP and coimmunoprecipitation experiments reveal that Atro interacts with the Drosophila GAGA Factor, Trithorax-like (Trl), and they bind to the same loci simultaneously. Phenotypic analyses of Trl and Atro clones suggest that Atro is required to modulate the transcription activation by Trl in larval imaginal discs. Taken together, these data indicate that Atro is a major Trl cofactor that functions to moderate developmental gene transcription.
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Affiliation(s)
- Kelvin Yeung
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Ann Boija
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Edvin Karlsson
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Division of CBRN Security and Defence, FOI-Swedish Defence Research Agency, Umeå, Sweden
| | - Per-Henrik Holmqvist
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Yonit Tsatskis
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Ilaria Nisoli
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, London, United Kingdom
| | - Damian Yap
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - Alireza Lorzadeh
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Michael Smith Laboratories, Vancouver, Canada
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Michelle Moksa
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Michael Smith Laboratories, Vancouver, Canada
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Martin Hirst
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Michael Smith Laboratories, Vancouver, Canada
- Canada’s Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Samuel Aparicio
- Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - Manolis Fanto
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King’s College London, London, United Kingdom
| | - Per Stenberg
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Division of CBRN Security and Defence, FOI-Swedish Defence Research Agency, Umeå, Sweden
| | - Mattias Mannervik
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Helen McNeill
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
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17
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Lomaev D, Mikhailova A, Erokhin M, Shaposhnikov AV, Moresco JJ, Blokhina T, Wolle D, Aoki T, Ryabykh V, Yates JR, Shidlovskii YV, Georgiev P, Schedl P, Chetverina D. The GAGA factor regulatory network: Identification of GAGA factor associated proteins. PLoS One 2017; 12:e0173602. [PMID: 28296955 PMCID: PMC5351981 DOI: 10.1371/journal.pone.0173602] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 02/23/2017] [Indexed: 11/24/2022] Open
Abstract
The Drosophila GAGA factor (GAF) has an extraordinarily diverse set of functions that include the activation and silencing of gene expression, nucleosome organization and remodeling, higher order chromosome architecture and mitosis. One hypothesis that could account for these diverse activities is that GAF is able to interact with partners that have specific and dedicated functions. To test this possibility we used affinity purification coupled with high throughput mass spectrometry to identify GAF associated partners. Consistent with this hypothesis the GAF interacting network includes a large collection of factors and complexes that have been implicated in many different aspects of gene activity, chromosome structure and function. Moreover, we show that GAF interactions with a small subset of partners is direct; however for many others the interactions could be indirect, and depend upon intermediates that serve to diversify the functional capabilities of the GAF protein.
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Affiliation(s)
- Dmitry Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Anna Mikhailova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Maksim Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | | | - James J. Moresco
- Department of Chemical Physiology, SR302B, The Scripps Research Institute, La Jolla, California, United States of America
| | - Tatiana Blokhina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Daniel Wolle
- Department of Molecular Biology Princeton University, Princeton, NJ, United States of America
| | - Tsutomu Aoki
- Department of Molecular Biology Princeton University, Princeton, NJ, United States of America
| | - Vladimir Ryabykh
- Institute of Animal Physiology, Biochemistry and Nutrition, Borovsk, Russia
| | - John R. Yates
- Department of Chemical Physiology, SR302B, The Scripps Research Institute, La Jolla, California, United States of America
| | | | - Pavel Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (DC); (PS); (PG)
| | - Paul Schedl
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Molecular Biology Princeton University, Princeton, NJ, United States of America
- * E-mail: (DC); (PS); (PG)
| | - Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (DC); (PS); (PG)
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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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19
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Karagodin DA, Battulina NV, Merkulova TI, Baricheva EM. The reasons of Trithorax-like expression disturbance in Trl 3609 allele of Drosophila melanogaster. DOKL BIOCHEM BIOPHYS 2017; 471:443-446. [PMID: 28058687 DOI: 10.1134/s1607672916060181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Indexed: 11/23/2022]
Abstract
The regulatory region of the Trl gene was analyzed using the mutation Trl 3609 , resulting from the insertion of the P-element into the promoter region of the gene as well as mutations obtained on its basis. It is shown that two last transcription start sites, which are most often used in vitro in S2 cells, are almost not used in vivo. Experimental data indicate that transcription terminators in transposons play an important role in the decrease in the transcription level of the recipient gene.
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Affiliation(s)
- D A Karagodin
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - N V Battulina
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - T I Merkulova
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - E M Baricheva
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia.
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20
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Oliva M, Butenko Y, Hsieh TF, Hakim O, Katz A, Smorodinsky NI, Michaeli D, Fischer RL, Ohad N. FIE, a nuclear PRC2 protein, forms cytoplasmic complexes in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6111-6123. [PMID: 27811080 PMCID: PMC5100023 DOI: 10.1093/jxb/erw373] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Polycomb group (PcG) proteins are evolutionarily conserved chromatin modifiers that regulate developmental pathways in plants. PcGs form nuclear multi-subunit Polycomb Repressive Complexes (PRCs). The PRC2 complex mediates gene repression via methylation of lysine 27 on histone H3, which consequently leads to chromatin condensation. In Arabidopsis thaliana, several PRC2 complexes with different compositions were identified, each controlling a particular developmental program.The core subunit FIE is crucial for PRC2 function throughout the plant life cycle, yet accurate information on its spatial and temporal localization was absent. This study focused on identifying FIE accumulation patterns, using microscopy and biochemical approaches. Analysing endogenous FIE and transgenic gFIE-green fluorescent protein fusion protein (gFIE-GFP) showed that FIE accumulates in the nuclei of every cell type examined. Interestingly, gFIE-GFP, as well as the endogenous FIE, also localized to the cytoplasm in all examined tissues. In both vegetative and reproductive organs, FIE formed cytoplasmic high-molecular-mass complexes, in parallel to the nuclear PRC2 complexes. Moreover, size-exclusion chromatography and bimolecular fluorescence complementation assays indicated that in inflorescences FIE formed a cytoplasmic complex with MEA, a PRC2 histone methyltransferase subunit. In contrast, CLF and SWN histone methyltransferases were strictly nuclear. Presence of PRC2 subunits in cytoplasmic complexes has not been previously described in plants. Our findings are in agreement with accumulating evidence demonstrating cytoplasmic localization and function of PcGs in metazoa. The cytosolic accumulation of PRC2 components in plants supports the model that PcGs have alternative non-nuclear functions that go beyond chromatin methylation.
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Affiliation(s)
- Moran Oliva
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- Department of Ornamental Horticulture and Plant Biotechnology, Agriculture Research Organization, The Volcani Center, PO Box 6, Beit Dagan, 50250, Israel
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Yana Butenko
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- Department of Plant Sciences, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Tzung-Fu Hsieh
- Plants for Human Health Institute, and Department of Plant and Microbial Biology, North Carolina State University, Kannapolis, NC 28081, USA
| | - Ofir Hakim
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Aviva Katz
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Nechama I Smorodinsky
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Daphna Michaeli
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Robert L Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
| | - Nir Ohad
- Department of Molecular Biology and Ecology of Plant, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- The Manna Center Program for Food Safety and Security, Tel Aviv University, 69978, Israel
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Phosphorylation-Dependent Targeting of Tetrahymena HP1 to Condensed Chromatin. mSphere 2016; 1:mSphere00142-16. [PMID: 27579368 PMCID: PMC4999919 DOI: 10.1128/msphere.00142-16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 07/25/2016] [Indexed: 01/16/2023] Open
Abstract
Compacting the genome to various degrees influences processes that use DNA as a template, such as gene transcription and replication. This project was aimed at learning more about the cellular mechanisms that control genome compaction. Posttranslational modifications of proteins involved in genome condensation are emerging as potentially important points of regulation. To help elucidate protein modifications and how they affect the function of condensation proteins, we investigated the phosphorylation of the chromatin protein called Hhp1 in the ciliated protozoan Tetrahymena thermophila. This is one of the first functional investigations of these modifications of a nonhistone chromatin condensation protein that acts on the ciliate genome, and discoveries will aid in identifying common, evolutionarily conserved strategies that control the dynamic compaction of genomes. The evolutionarily conserved proteins related to heterochromatin protein 1 (HP1), originally described in Drosophila, are well known for their roles in heterochromatin assembly and gene silencing. Targeting of HP1 proteins to specific chromatin locales is mediated, at least in part, by the HP1 chromodomain, which binds to histone H3 methylated at lysine 9 that marks condensed regions of the genome. Mechanisms that regulate HP1 targeting are emerging from studies with yeast and metazoans and point to roles for posttranslational modifications. Here, we report that modifications of an HP1 homolog (Hhp1) in the ciliate model Tetrahymena thermophila correlated with the physiological state and with nuclear differentiation events involving the restructuring of chromatin. Results support the model in which Hhp1 chromodomain binds lysine 27-methylated histone H3, and we show that colocalization with this histone mark depends on phosphorylation at a single Cdc2/Cdk1 kinase site in the “hinge region” adjacent to the chromodomain. These findings help elucidate important functional roles of reversible posttranslational modifications of proteins in the HP1 family, in this case, regulating the targeting of a ciliate HP1 to chromatin regions marked with methylated H3 lysine 27. IMPORTANCE Compacting the genome to various degrees influences processes that use DNA as a template, such as gene transcription and replication. This project was aimed at learning more about the cellular mechanisms that control genome compaction. Posttranslational modifications of proteins involved in genome condensation are emerging as potentially important points of regulation. To help elucidate protein modifications and how they affect the function of condensation proteins, we investigated the phosphorylation of the chromatin protein called Hhp1 in the ciliated protozoan Tetrahymena thermophila. This is one of the first functional investigations of these modifications of a nonhistone chromatin condensation protein that acts on the ciliate genome, and discoveries will aid in identifying common, evolutionarily conserved strategies that control the dynamic compaction of genomes.
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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: 56] [Impact Index Per Article: 7.0] [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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Blanch M, Piñeyro D, Bernués J. New insights for Drosophila GAGA factor in larvae. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150011. [PMID: 26064623 PMCID: PMC4448821 DOI: 10.1098/rsos.150011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 02/17/2015] [Indexed: 06/04/2023]
Abstract
GAGA factor plays important roles during Drosophila embryogenesis and its maternal contribution is essential for early development. Here, the role of GAGA factor was studied in 3rd instar larvae using depletion and overexpression conditions in wing disc and transcriptome analysis. We found that genes changing expression were different to those previously described using GAGA mutants in embryos. No apparent phenotypes on GAGA depletion could usually be observed at larval stages in imaginal discs but a strong effect on salivary gland polytene chromosomes was observed. In the adult, GAGA depletion produced many defects like abnormal cell proliferation in the wing, impaired dorsal closure and resulted in homeotic transformation of abdominal segment A5. Unexpectedly, no effects on Ultrabithorax expression were observed. Short overexpression of GAGA factor in 3rd instar larvae also resulted in activation of a set of genes not previously described to be under GAGA regulation, and in lethality at pupa. Our results suggest a little contribution of GAGA factor on gene transcription in wing discs and a change of the genes regulated in comparison with embryo. GAGA factor activity thus correlates with the global changes in gene expression that take place at the embryo-to-larva and, later, at the larva-to-pupa transitions.
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Affiliation(s)
- Marta Blanch
- Departament de Genòmica Molecular, Institut de Biologia Molecular de Barcelona-CSIC, Parc Científic de Barcelona, Barcelona 08028, Spain
- Cell and Developmental Biology Programme, Institute for Research in Biomedicine, Barcelona, Spain
| | - David Piñeyro
- Departament de Genòmica Molecular, Institut de Biologia Molecular de Barcelona-CSIC, Parc Científic de Barcelona, Barcelona 08028, Spain
- Cell and Developmental Biology Programme, Institute for Research in Biomedicine, Barcelona, Spain
| | - Jordi Bernués
- Departament de Genòmica Molecular, Institut de Biologia Molecular de Barcelona-CSIC, Parc Científic de Barcelona, Barcelona 08028, Spain
- Cell and Developmental Biology Programme, Institute for Research in Biomedicine, Barcelona, Spain
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Product binding enforces the genomic specificity of a yeast polycomb repressive complex. Cell 2014; 160:204-18. [PMID: 25533783 DOI: 10.1016/j.cell.2014.11.039] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/30/2014] [Accepted: 11/12/2014] [Indexed: 11/22/2022]
Abstract
We characterize the Polycomb system that assembles repressive subtelomeric domains of H3K27 methylation (H3K27me) in the yeast Cryptococcus neoformans. Purification of this PRC2-like protein complex reveals orthologs of animal PRC2 components as well as a chromodomain-containing subunit, Ccc1, which recognizes H3K27me. Whereas removal of either the EZH or EED ortholog eliminates H3K27me, disruption of mark recognition by Ccc1 causes H3K27me to redistribute. Strikingly, the resulting pattern of H3K27me coincides with domains of heterochromatin marked by H3K9me. Indeed, additional removal of the C. neoformans H3K9 methyltransferase Clr4 results in loss of both H3K9me and the redistributed H3K27me marks. These findings indicate that the anchoring of a chromatin-modifying complex to its product suppresses its attraction to a different chromatin type, explaining how enzymes that act on histones, which often harbor product recognition modules, may deposit distinct chromatin domains despite sharing a highly abundant and largely identical substrate-the nucleosome.
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Kahn TG, Stenberg P, Pirrotta V, Schwartz YB. Combinatorial interactions are required for the efficient recruitment of pho repressive complex (PhoRC) to polycomb response elements. PLoS Genet 2014; 10:e1004495. [PMID: 25010632 PMCID: PMC4091789 DOI: 10.1371/journal.pgen.1004495] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/23/2014] [Indexed: 12/20/2022] Open
Abstract
Polycomb Group (PcG) proteins are epigenetic repressors that control metazoan development and cell differentiation. In Drosophila, PcG proteins form five distinct complexes targeted to genes by Polycomb Response Elements (PREs). Of all PcG complexes PhoRC is the only one that contains a sequence-specific DNA binding subunit (PHO or PHOL), which led to a model that places PhoRC at the base of the recruitment hierarchy. Here we demonstrate that in vivo PHO is preferred to PHOL as a subunit of PhoRC and that PHO and PHOL associate with PREs and a subset of transcriptionally active promoters. Although the binding to the promoter sites depends on the quality of recognition sequences, the binding to PREs does not. Instead, the efficient recruitment of PhoRC to PREs requires the SFMBT subunit and crosstalk with Polycomb Repressive Complex 1. We find that human YY1 protein, the ortholog of PHO, binds sites at active promoters in the human genome but does not bind most PcG target genes, presumably because the interactions involved in the targeting to Drosophila PREs are lost in the mammalian lineage. We conclude that the recruitment of PhoRC to PREs is based on combinatorial interactions and propose that such a recruitment strategy is important to attenuate the binding of PcG proteins when the target genes are transcriptionally active. Our findings allow the appropriate placement of PhoRC in the PcG recruitment hierarchy and provide a rationale to explain why YY1 is unlikely to serve as a general recruiter of mammalian Polycomb complexes despite its reported ability to participate in PcG repression in flies. Polycomb Group (PcG) proteins are epigenetic repressors essential for development and cell differentiation. PcG proteins form five complexes targeted to specific genes by Polycomb Response Elements (PREs). How PcG complexes are recruited to PREs is poorly understood. Here we investigate the recruitment of PhoRC, a seemingly simple case of a complex that contains a sequence-specific DNA binding subunit: PHO (or the related protein PHOL). Unexpectedly, we find that the sequence specific binding of PHO is not a primary determinant for recruitment of PhoRC to PRE, which depends on the non-DNA binding subunit SFMBT and cross-talk with another PcG complex, PRC1. The binding of PhoRC is helped by PRC1 and, in turn, may stabilize the binding of PRC1. We propose that the recruitment based on combinatorial interactions enables the conditional binding of PcG proteins, which is important for switching the state of the target genes from repressed to active. The critical role of the cross-talk between PhoRC and PRC1 is further supported by the finding that in mammals, where the protein domains linking the two complexes are missing, the PHO ortholog YY1 has no implication in PcG repression, despite 100% conservation between DNA binding domains of YY1 and PHO.
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Affiliation(s)
- Tatyana G. Kahn
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Per Stenberg
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Computational Life Science Cluster (CLiC), Umeå University, Umeå, Sweden
| | - Vincenzo Pirrotta
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (VP); (YBS)
| | - Yuri B. Schwartz
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (VP); (YBS)
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Dorogova NV, Fedorova EV, Bolobolova EU, Ogienko AA, Baricheva EM. GAGA protein is essential for male germ cell development in Drosophila. Genesis 2014; 52:738-51. [PMID: 24817547 DOI: 10.1002/dvg.22789] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/06/2014] [Accepted: 05/07/2014] [Indexed: 12/13/2022]
Abstract
The Drosophila Trithorax-like (Trl) gene encodes a GAGA factor which regulates a number of developmentally important genes. In this study, we identify a new function for Drosophila GAGA factor in male germ cell development. Trl mutants carrying strong hypomorphic alleles display loss of primordial germ cells during their migration in embryogenesis and severe disruption in mitochondria structure during early spermatogenesis. The mutation resulted in small testes formation, a deficit of germ cells, abnormal mitochondrial morphogenesis, spermatocyte death through autophagy, and partial or complete male sterility. Pleiotropic mutation effects can be explained by the misexpression of GAGA factor target genes, the products of which are required for germ cell progression into mature sperm.
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Affiliation(s)
- Natalia V Dorogova
- Institute of Cytology & Genetics of the Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, Novosibirsk, 630090, Russia
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28
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Lin Y, Dong C, Zhou B. Epigenetic Regulation of EMT: The Snail Story. Curr Pharm Des 2014; 20:1698-705. [DOI: 10.2174/13816128113199990512] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 07/18/2013] [Indexed: 12/22/2022]
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Schorderet P, Lonfat N, Darbellay F, Tschopp P, Gitto S, Soshnikova N, Duboule D. A genetic approach to the recruitment of PRC2 at the HoxD locus. PLoS Genet 2013; 9:e1003951. [PMID: 24244202 PMCID: PMC3820793 DOI: 10.1371/journal.pgen.1003951] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/27/2013] [Indexed: 01/01/2023] Open
Abstract
Polycomb group (PcG) proteins are essential for the repression of key factors during early development. In Drosophila, the polycomb repressive complexes (PRC) associate with defined polycomb response DNA elements (PREs). In mammals, however, the mechanisms underlying polycomb recruitment at targeted loci are poorly understood. We have used an in vivo approach to identify DNA sequences of importance for the proper recruitment of polycomb proteins at the HoxD locus. We report that various genomic re-arrangements of the gene cluster do not strongly affect PRC2 recruitment and that relatively small polycomb interacting sequences appear necessary and sufficient to confer polycomb recognition and targeting to ectopic loci. In addition, a high GC content, while not sufficient to recruit PRC2, may help its local spreading. We discuss the importance of PRC2 recruitment over Hox gene clusters in embryonic stem cells, for their subsequent coordinated transcriptional activation during development. Hox genes are essential for the proper organization of structures along the developing vertebrate body axis. These genes must be activated at a precise time and their premature transcription is deleterious to the organism. Early on, Hox gene clusters are covered by Polycomb Repressive protein Complexes (PRCs), which help keep these genes silent. However, the mechanism(s) that selectively recruit PRCs to these particular genomic loci remains elusive. We have used a collection of mutant mice carrying a set of deletions inside and outside the HoxD cluster to try and detect the presence of any DNA sequence of particular importance in this mechanism. We conclude that a range of low affinity sequences synergize to recruit PRCs over the gene cluster, which makes this process very robust and resistant to genetic perturbations.
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Affiliation(s)
- Patrick Schorderet
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- School of Life Sciences, Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Nicolas Lonfat
- School of Life Sciences, Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Fabrice Darbellay
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- School of Life Sciences, Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Patrick Tschopp
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- Department of Genetics and Evolution, University of Geneva, Sciences III, Geneva, Switzerland
| | - Sandra Gitto
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- Department of Genetics and Evolution, University of Geneva, Sciences III, Geneva, Switzerland
| | - Natalia Soshnikova
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- School of Life Sciences, Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Denis Duboule
- National Research Center ‘Frontiers in Genetics’, Geneva, Switzerland
- School of Life Sciences, Federal Institute of Technology (EPFL), Lausanne, Switzerland
- Department of Genetics and Evolution, University of Geneva, Sciences III, Geneva, Switzerland
- * E-mail: ,
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Wu HA, Balsbaugh JL, Chandler H, Georgilis A, Zullow H, Shabanowitz J, Hunt DF, Gil J, Peters G, Bernstein E. Mitogen-activated protein kinase signaling mediates phosphorylation of polycomb ortholog Cbx7. J Biol Chem 2013; 288:36398-408. [PMID: 24194518 DOI: 10.1074/jbc.m113.486266] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cbx7 is one of five mammalian orthologs of the Drosophila Polycomb. Cbx7 recognizes methylated lysine residues on the histone H3 tail and contributes to gene silencing in the context of the Polycomb repressive complex 1 (PRC1). However, our knowledge of Cbx7 post-translational modifications remains limited. Through combined biochemical and mass spectrometry approaches, we report a novel phosphorylation site on mouse Cbx7 at residue Thr-118 (Cbx7T118ph), near the highly conserved Polycomb box. The generation of a site-specific antibody to Cbx7T118ph demonstrates that Cbx7 is phosphorylated via MAPK signaling. Furthermore, we find Cbx7T118 phosphorylation in murine mammary carcinoma cells, which can be blocked by MEK inhibitors. Upon EGF stimulation, Cbx7 interacts robustly with other members of PRC1. To test the role of Cbx7T118 phosphorylation in gene silencing, we employed a RAS-induced senescence model system. We demonstrate that Cbx7T118 phosphorylation moderately enhances repression of its target gene p16. In summary, we have identified and characterized a novel MAPK-mediated phosphorylation site on Cbx7 and propose that mitogen signaling to the chromatin template regulates PRC1 function.
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Affiliation(s)
- Hsan-au Wu
- From the Department of Oncological Sciences and
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31
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Klose RJ, Cooper S, Farcas AM, Blackledge NP, Brockdorff N. Chromatin sampling--an emerging perspective on targeting polycomb repressor proteins. PLoS Genet 2013; 9:e1003717. [PMID: 23990804 PMCID: PMC3749931 DOI: 10.1371/journal.pgen.1003717] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Robert J. Klose
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail: (RJK); (NB)
| | - Sarah Cooper
- Laboratory of Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Anca M. Farcas
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Neil P. Blackledge
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Neil Brockdorff
- Laboratory of Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail: (RJK); (NB)
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Piñeyro D, Blanch M, Badal M, Kosoy A, Bernués J. GAGA factor repression of transcription is a rare event but the negative regulation of Trl is conserved in Drosophila species. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1056-65. [PMID: 23860261 DOI: 10.1016/j.bbagrm.2013.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/02/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
Abstract
GAGA is a highly conserved Drosophila transcription factor encoded by the Trithorax-like (Trl) gene. While GAGA usually activates transcription, it represses its own promoter. Here we show that GAGA-mediated repression of Trl is conserved between two distant Drosophila species. A detailed promoter study showed that GAGA repressive activity can't be attributed to any discrete element in the Trl promoter. Genome-wide analysis of the transcriptome in S2 cells indicated that repression of Trl is very likely unique, being GAGA factor a transactivator for all the other promoters. Taken together, our results suggest a new mechanism to explain GAGA-mediated repression that involves a dose-dependent change in the architecture of the Trl promoter.
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Affiliation(s)
- David Piñeyro
- Departament. de Genòmica Molecular, Institut de Biologia Molecular de Barcelona-CSIC, Parc Científic de Barcelona, 08028 Barcelona, Spain; Cell and Developmental Biology Programme, Institute for Research in Biomedicine, Barcelona, Spain
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Lindner M, Simonini S, Kooiker M, Gagliardini V, Somssich M, Hohenstatt M, Simon R, Grossniklaus U, Kater MM. TAF13 interacts with PRC2 members and is essential for Arabidopsis seed development. Dev Biol 2013; 379:28-37. [PMID: 23506837 DOI: 10.1016/j.ydbio.2013.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 11/24/2022]
Abstract
TBP-Associated Factors (TAFs) are components of complexes like TFIID, TFTC, SAGA/STAGA and SMAT that are important for the activation of transcription, either by establishing the basic transcription machinery or by facilitating histone acetylation. However, in Drosophila embryos several TAFs were shown to be associated with the Polycomb Repressive Complex 1 (PRC1), even though the role of this interaction remains unclear. Here we show that in Arabidopsis TAF13 interacts with MEDEA and SWINGER, both members of a plant variant of Polycomb Repressive Complex 2 (PRC2). PRC2 variants play important roles during the plant life cycle, including seed development. The taf13 mutation causes seed defects, showing embryo arrest at the 8-16 cell stage and over-proliferation of the endosperm in the chalazal region, which is typical for Arabidopsis PRC2 mutants. Our data suggest that TAF13 functions together with PRC2 in transcriptional regulation during seed development.
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Affiliation(s)
- Matias Lindner
- Dipartimento di BioScienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
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34
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Golbabapour S, Majid NA, Hassandarvish P, Hajrezaie M, Abdulla MA, Hadi AHA. Gene silencing and Polycomb group proteins: an overview of their structure, mechanisms and phylogenetics. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2013; 17:283-96. [PMID: 23692361 PMCID: PMC3662373 DOI: 10.1089/omi.2012.0105] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
DNA methylation, histone modifications, and chromatin configuration are crucially important in the regulation of gene expression. Among these epigenetic mechanisms, silencing the expression of certain genes depending on developmental stage and tissue specificity is a key repressive system in genome programming. Polycomb (Pc) proteins play roles in gene silencing through different mechanisms. These proteins act in complexes and govern the histone methylation profiles of a large number of genes that regulate various cellular pathways. This review focuses on two main Pc complexes, Pc repressive complexes 1 and 2, and their phylogenetic relationship, structures, and function. The dynamic roles of these complexes in silencing will be discussed herein, with a focus on the recruitment of Pc complexes to target genes and the key factors involved in their recruitment.
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Affiliation(s)
- Shahram Golbabapour
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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35
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Ahanger SH, Srinivasan A, Vasanthi D, Shouche YS, Mishra RK. Conserved boundary elements from the Hox complex of mosquito, Anopheles gambiae. Nucleic Acids Res 2012; 41:804-16. [PMID: 23221647 PMCID: PMC3553964 DOI: 10.1093/nar/gks1178] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The conservation of hox genes as well as their genomic organization across the phyla suggests that this system of anterior–posterior axis formation arose early during evolution and has come under strong selection pressure. Studies in the split Hox cluster of Drosophila have shown that proper expression of hox genes is dependent on chromatin domain boundaries that prevent inappropriate interactions among different types of cis-regulatory elements. To investigate whether boundary function and their role in regulation of hox genes is conserved in insects with intact Hox clusters, we used an algorithm to locate potential boundary elements in the Hox complex of mosquito, Anopheles gambiae. Several potential boundary elements were identified that could be tested for their functional conservation. Comparative analysis revealed that like Drosophila, the bithorax region in A. gambiae contains an extensive array of boundaries and enhancers organized into domains. We analysed a subset of candidate boundary elements and show that they function as enhancer blockers in Drosophila. The functional conservation of boundary elements from mosquito in fly suggests that regulation of hox genes involving chromatin domain boundaries is an evolutionary conserved mechanism and points to an important role of such elements in key developmentally regulated loci.
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36
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Simonini S, Roig-Villanova I, Gregis V, Colombo B, Colombo L, Kater MM. Basic pentacysteine proteins mediate MADS domain complex binding to the DNA for tissue-specific expression of target genes in Arabidopsis. THE PLANT CELL 2012; 24:4163-72. [PMID: 23054472 PMCID: PMC3517243 DOI: 10.1105/tpc.112.103952] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Basic pentacysteine (BPC) transcription factors have been identified in a large variety of plant species. In Arabidopsis thaliana there are seven BPC genes, which, except for BPC5, are expressed ubiquitously. BPC genes are functionally redundant in a wide range of developmental processes. Recently, we reported that BPC1 binds to guanine and adenine (GA)-rich consensus sequences in the seedstick (STK) promoter in vitro and induces conformational changes. Here we show by chromatin immunoprecipitation experiments that in vivo BPCs also bind to the consensus boxes, and when these were mutated, expression from the STK promoter was derepressed, resulting in ectopic expression in the inflorescence. We also reveal that short vegetative phase (SVP) is a direct regulator of STK. SVP is a floral meristem identity gene belonging to the MADS box gene family. The SVP-APETALA1 (AP1) dimer recruits the SEUSS (SEU)-LEUNIG (LUG) transcriptional cosuppressor to repress floral homeotic gene expression in the floral meristem. Interestingly, we found that GA consensus sequences in the STK promoter to which BPCs bind are essential for recruitment of the corepressor complex to this promoter. Our data suggest that we have identified a new regulatory mechanism controlling plant gene expression that is probably generally used, when considering BPCs' wide expression profile and the frequent presence of consensus binding sites in plant promoters.
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Affiliation(s)
- Sara Simonini
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Irma Roig-Villanova
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Veronica Gregis
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Bilitis Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Lucia Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
- Consiglio Nazionale delle Richerche, Istituto di Biofisica, Università degli Studi di Milano, 20133 Milano, Italy
| | - Martin M. Kater
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
- Address correspondence to
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Kurogi T, Inoue H, Guo Y, Nobukiyo A, Nohara K, Kanno M. A Methyl-Deficient Diet Modifies Early B Cell Development. Pathobiology 2012; 79:209-18. [DOI: 10.1159/000337290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 02/13/2012] [Indexed: 01/04/2023] Open
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Drosophila melanogaster dHCF interacts with both PcG and TrxG epigenetic regulators. PLoS One 2011; 6:e27479. [PMID: 22174740 PMCID: PMC3234250 DOI: 10.1371/journal.pone.0027479] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 10/18/2011] [Indexed: 11/19/2022] Open
Abstract
Repression and activation of gene transcription involves multiprotein complexes that modify chromatin structure. The integration of these complexes at regulatory sites can be assisted by co-factors that link them to DNA-bound transcriptional regulators. In humans, one such co-factor is the herpes simplex virus host-cell factor 1 (HCF-1), which is implicated in both activation and repression of transcription. We show here that disruption of the gene encoding the Drosophila melanogaster homolog of HCF-1, dHCF, leads to a pleiotropic phenotype involving lethality, sterility, small size, apoptosis, and morphological defects. In Drosophila, repressed and activated transcriptional states of cell fate-determining genes are maintained throughout development by Polycomb Group (PcG) and Trithorax Group (TrxG) genes, respectively. dHCF mutant flies display morphological phenotypes typical of TrxG mutants and dHCF interacts genetically with both PcG and TrxG genes. Thus, dHCF inactivation enhances the mutant phenotypes of the Pc PcG as well as brm and mor TrxG genes, suggesting that dHCF possesses Enhancer of TrxG and PcG (ETP) properties. Additionally, dHCF interacts with the previously established ETP gene skd. These pleiotropic phenotypes are consistent with broad roles for dHCF in both activation and repression of transcription during fly development.
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Gutiérrez L, Oktaba K, Scheuermann JC, Gambetta MC, Ly-Hartig N, Müller J. The role of the histone H2A ubiquitinase Sce in Polycomb repression. Development 2011; 139:117-27. [PMID: 22096074 PMCID: PMC3253035 DOI: 10.1242/dev.074450] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Polycomb group (PcG) proteins exist in multiprotein complexes that modify chromatin to repress transcription. Drosophila PcG proteins Sex combs extra (Sce; dRing) and Posterior sex combs (Psc) are core subunits of PRC1-type complexes. The Sce:Psc module acts as an E3 ligase for monoubiquitylation of histone H2A, an activity thought to be crucial for repression by PRC1-type complexes. Here, we created an Sce knockout allele and show that depletion of Sce results in loss of H2A monoubiquitylation in developing Drosophila. Genome-wide profiling identified a set of target genes co-bound by Sce and all other PRC1 subunits. Analyses in mutants lacking individual PRC1 subunits reveals that these target genes comprise two distinct classes. Class I genes are misexpressed in mutants lacking any of the PRC1 subunits. Class II genes are only misexpressed in animals lacking the Psc-Su(z)2 and Polyhomeotic (Ph) subunits but remain stably repressed in the absence of the Sce and Polycomb (Pc) subunits. Repression of class II target genes therefore does not require Sce and H2A monoubiquitylation but might rely on the ability of Psc-Su(z)2 and Ph to inhibit nucleosome remodeling or to compact chromatin. Similarly, Sce does not provide tumor suppressor activity in larval tissues under conditions in which Psc-Su(z)2, Ph and Pc show such activity. Sce and H2A monoubiquitylation are therefore only crucial for repression of a subset of genes and processes regulated by PRC1-type complexes. Sce synergizes with the Polycomb repressive deubiquitinase (PR-DUB) complex to repress transcription at class I genes, suggesting that H2A monoubiquitylation must be appropriately balanced for their transcriptional repression.
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Affiliation(s)
- Luis Gutiérrez
- EMBL, Gene Expression Programme, Meyerhofstr. 1, 69117 Heidelberg, Germany
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40
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Butenko Y, Ohad N. Polycomb-group mediated epigenetic mechanisms through plant evolution. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:395-406. [PMID: 21664995 DOI: 10.1016/j.bbagrm.2011.05.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/23/2011] [Accepted: 05/26/2011] [Indexed: 12/01/2022]
Abstract
Polycomb Group (PcG) proteins form an epigenetic "memory system", conserved in both plants and animals, controlling global gene expression during development via histone modifications. The role of PcG proteins in plants was primarily explored in Arabidopsis thaliana, where PcG regulation of developmental processes was demonstrated throughout the plant life cycle. Our knowledge about the PcG machinery in terrestrial plants other than Arabidopsis began to accumulate only in recent years. In this review we summarize recent emerging data on the evolution and diversification of PcG mechanisms in various phyla, from early-diverging plants, including members of the Chlorophyte algae, through bryophytes and flowering plants. We describe the compositions of the PcG gene families, their so-far studied expression profiles, and finally summarize commonalities vs. differences among PcG functions across the various species. This article is part of a Special Issue entitled: Epigenetic control of cellular and developmental processes in plants.
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Affiliation(s)
- Yana Butenko
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, Israel
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Mouchel-Vielh E, Rougeot J, Decoville M, Peronnet F. The MAP kinase ERK and its scaffold protein MP1 interact with the chromatin regulator Corto during Drosophila wing tissue development. BMC DEVELOPMENTAL BIOLOGY 2011; 11:17. [PMID: 21401930 PMCID: PMC3062617 DOI: 10.1186/1471-213x-11-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 03/14/2011] [Indexed: 11/12/2022]
Abstract
Background Mitogen-activated protein kinase (MAPK) cascades (p38, JNK, ERK pathways) are involved in cell fate acquisition during development. These kinase modules are associated with scaffold proteins that control their activity. In Drosophila, dMP1, that encodes an ERK scaffold protein, regulates ERK signaling during wing development and contributes to intervein and vein cell differentiation. Functional relationships during wing development between a chromatin regulator, the Enhancer of Trithorax and Polycomb Corto, ERK and its scaffold protein dMP1, are examined here. Results Genetic interactions show that corto and dMP1 act together to antagonize rolled (which encodes ERK) in the future intervein cells, thus promoting intervein fate. Although Corto, ERK and dMP1 are present in both cytoplasmic and nucleus compartments, they interact exclusively in nucleus extracts. Furthermore, Corto, ERK and dMP1 co-localize on several sites on polytene chromosomes, suggesting that they regulate gene expression directly on chromatin. Finally, Corto is phosphorylated. Interestingly, its phosphorylation pattern differs between cytoplasm and nucleus and changes upon ERK activation. Conclusions Our data therefore suggest that the Enhancer of Trithorax and Polycomb Corto could participate in regulating vein and intervein genes during wing tissue development in response to ERK signaling.
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Affiliation(s)
- Emmanuèle Mouchel-Vielh
- Université Pierre et Marie Curie-Paris 6; Centre National de la Recherche Scientifique; UMR7622, Laboratoire de Biologie du Développement, Equipe Chromatine et Développement, 75005 Paris, France.
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Comparative analysis of chromatin binding by Sex Comb on Midleg (SCM) and other polycomb group repressors at a Drosophila Hox gene. Mol Cell Biol 2010; 30:2584-93. [PMID: 20351181 DOI: 10.1128/mcb.01451-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Sex Comb on Midleg (SCM) is a transcriptional repressor in the Polycomb group (PcG), but its molecular role in PcG silencing is not known. Although SCM can interact with Polycomb repressive complex 1 (PRC1) in vitro, biochemical studies have indicated that SCM is not a core constituent of PRC1 or PRC2. Nevertheless, SCM is just as critical for Drosophila Hox gene silencing as canonical subunits of these well-characterized PcG complexes. To address functional relationships between SCM and other PcG components, we have performed chromatin immunoprecipitation studies using cultured Drosophila Schneider line 2 (S2) cells and larval imaginal discs. We find that SCM associates with a Polycomb response element (PRE) upstream of the Ubx gene which also binds PRC1, PRC2, and the DNA-binding PcG protein Pleiohomeotic (PHO). However, SCM is retained at this Ubx PRE despite genetic disruption or knockdown of PHO, PRC1, or PRC2, suggesting that SCM chromatin targeting does not require prior association of these other PcG components. Chromatin immunoprecipitations (IPs) to test the consequences of SCM genetic disruption or knockdown revealed that PHO association is unaffected, but reduced levels of PRE-bound PRC2 and PRC1 were observed. We discuss these results in light of current models for recruitment of PcG complexes to chromatin targets.
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43
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Blackledge NP, Klose RJ. Histone lysine methylation: an epigenetic modification? Epigenomics 2010; 2:151-61. [DOI: 10.2217/epi.09.42] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Histone lysine methylation regulates a variety of nuclear processes including transcription and maintenance of genome integrity. Many attributes of the histone lysine methylation system suggest that it might also contribute to epigenetic memory. Here, we examine the recent advances in our understanding of three intensely-studied histone lysine methylation marks, focusing on the potential mechanisms by which these marks may be maintained during cell proliferation and adhere to the principles of epigenetics.
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Affiliation(s)
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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44
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Beck S, Faradji F, Brock H, Peronnet F. Maintenance of Hox Gene Expression Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 689:41-62. [DOI: 10.1007/978-1-4419-6673-5_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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45
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Fedorova EV, Pindyurin AV, Baricheva EM. Maintenance of the patterns of expression of homeotic genes in the development of Drosophila melanogaster by proteins of the polycomb, trithorax, and ETP groups. RUSS J GENET+ 2009. [DOI: 10.1134/s1022795409100019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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46
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Kumar RP. Polycomb group proteins: remembering how to catch chromatin during replication. Bioessays 2009; 31:822-5. [PMID: 19554611 DOI: 10.1002/bies.200900059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Polycomb group (PcG) proteins maintain the expression state of PcG-responsive genes during development of multicellular organisms. Recent observations suggest that "the H3K27me3 modification" acts to maintain Polycomb repressive complex (PRC) 2, the enzyme that creates this modification, on replicating chromatin. This could in turn promote propagation of H3K27me3 on newly replicated daughter chromatin, and promote recruitment of PRC1. Other work suggests that PRC1-class complexes can be maintained on replicating chromatin, at least in vitro, independently of H3K27me3. Thus, histone modifications and PcG proteins themselves may both be maintained through replication.
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Boukarabila H, Saurin AJ, Batsché E, Mossadegh N, van Lohuizen M, Otte AP, Pradel J, Muchardt C, Sieweke M, Duprez E. The PRC1 Polycomb group complex interacts with PLZF/RARA to mediate leukemic transformation. Genes Dev 2009; 23:1195-206. [PMID: 19451220 DOI: 10.1101/gad.512009] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ectopic repression of retinoic acid (RA) receptor target genes by PML/RARA and PLZF/RARA fusion proteins through aberrant recruitment of nuclear corepressor complexes drives cellular transformation and acute promyelocytic leukemia (APL) development. In the case of PML/RARA, this repression can be reversed through treatment with all-trans RA (ATRA), leading to leukemic remission. However, PLZF/RARA ectopic repression is insensitive to ATRA, resulting in persistence of the leukemic diseased state after treatment, a phenomenon that is still poorly understood. Here we show that, like PML/RARA, PLZF/RARA expression leads to recruitment of the Polycomb-repressive complex 2 (PRC2) Polycomb group (PcG) complex to RA response elements. However, unlike PML/RARA, PLZF/RARA directly interacts with the PcG protein Bmi-1 and forms a stable component of the PRC1 PcG complex, resulting in PLZF/RARA-dependent ectopic recruitment of PRC1 to RA response elements. Upon treatment with ATRA, ectopic recruitment of PRC2 by either PML/RARA or PLZF/RARA is lost, whereas PRC1 recruited by PLZF/RARA remains, resulting in persistent RA-insensitive gene repression. We further show that Bmi-1 is essential for the PLZF/RARA cellular transformation property and implicates a central role for PRC1 in PLZF/RARA-mediated myeloid leukemic development.
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Affiliation(s)
- Hanane Boukarabila
- Centre d'Immunologie de Marseille-Luminy (CIML), Université de la Méditerranée, Campus de Luminy, 13288 Marseille Cedex 09, France
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Hansen KH, Bracken AP, Pasini D, Dietrich N, Gehani SS, Monrad A, Rappsilber J, Lerdrup M, Helin K. A model for transmission of the H3K27me3 epigenetic mark. Nat Cell Biol 2008; 10:1291-300. [PMID: 18931660 DOI: 10.1038/ncb1787] [Citation(s) in RCA: 552] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 09/08/2008] [Indexed: 12/14/2022]
Abstract
Organization of chromatin by epigenetic mechanisms is essential for establishing and maintaining cellular identity in developing and adult organisms. A key question that remains unresolved about this process is how epigenetic marks are transmitted to the next cell generation during cell division. Here we provide a model to explain how trimethylated Lys 27 of histone 3 (H3K27me3), which is catalysed by the EZH2-containing Polycomb Repressive Complex 2 (PRC2), is maintained in proliferating cells. We show that the PRC2 complex binds to the H3K27me3 mark and colocalizes with this mark in G1 phase and with sites of ongoing DNA replication. Efficient binding requires an intact trimeric PRC2 complex containing EZH2, EED and SUZ12, but is independent of the catalytic SET domain of EZH2. Using a heterologous reporter system, we show that transient recruitment of the PRC2 complex to chromatin, upstream of the transcriptional start site, is sufficient to maintain repression through endogenous PRC2 during subsequent cell divisions. Thus, we suggest that once the H3K27me3 is established, it recruits the PRC2 complex to maintain the mark at sites of DNA replication, leading to methylation of H3K27 on the daughter strands during incorporation of newly synthesized histones. This mechanism ensures maintenance of the H3K27me3 epigenetic mark in proliferating cells, not only during DNA replication when histones synthesized de novo are incorporated, but also outside S phase, thereby preserving chromatin structure and transcriptional programs.
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Affiliation(s)
- Klaus H Hansen
- Biotech Research & Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N., Denmark.
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The polycomb repressive complex 2 is a potential target of SUMO modifications. PLoS One 2008; 3:e2704. [PMID: 18628979 PMCID: PMC2442188 DOI: 10.1371/journal.pone.0002704] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 06/18/2008] [Indexed: 01/27/2023] Open
Abstract
Background The Polycomb Repressive Complex 2 (PRC2) functions as a transcriptional repressor through a mechanism that involves methylation of Histone H3 at lysine 27. The PRC2 complex activity is essential for cellular proliferation, development, and cell fate decisions. PRC2 target genes include important regulators of development and proliferation as well as tumor suppressor genes. Consistent with this, the activity of several Polycomb group (PcG) proteins is deregulated in human cancer suggesting an important role for PcGs in tumor development. Whereas the downstream functions of PcGs are well characterized, the mechanisms of their recruitment to target genes and the regulation of their activity are not fully understood. Principal Findings Here we show that the two PRC2 components SUZ12 and EZH2 are sumoylated in vitro and in vivo. Among several putative sumoylation sites we have mapped the major site of SUZ12 sumoylation. Furthermore, we show that SUZ12 interacts with the E2-conjugating enzyme UBC9 both in vitro and in vivo and that mutation of the SUZ12 sumoylation site does not abolish this binding. Finally, we provide evidence that the E3-ligase PIASXβ interacts and enhances the sumoylation of SUZ12 in vivo suggesting that PIASXβ could function as an E3-ligase for SUZ12. Conclusions Taken together, our data identify sumoylation as a novel post-translational modification of components of the PRC2 complex, which could suggest a potential new mechanism to modulate PRC2 repressive activity. Further work aimed to identify the physiological conditions for these modifications will be required to understand the role of SUZ12 and EZH2 sumoylation in PcG-mediated epigenetic regulation of transcription.
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Polycomb complex 2 is required for E-cadherin repression by the Snail1 transcription factor. Mol Cell Biol 2008; 28:4772-81. [PMID: 18519590 DOI: 10.1128/mcb.00323-08] [Citation(s) in RCA: 328] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The transcriptional factor Snail1 is a repressor of E-cadherin (CDH1) gene expression essential for triggering epithelial-mesenchymal transition. Snail1 represses CDH1, directly binding its promoter and inducing the synthesis of the Zeb1 repressor. In this article, we show that repression of CDH1 by Snail1, but not by Zeb1, is dependent on the activity of Polycomb repressive complex 2 (PRC2). Embryonic stem (ES) cells null for Suz12, one of the components of PRC2, show higher levels of Cdh1 mRNA than control ES cells. In tumor cells, interference of PRC2 activity prevents the ability of Snail1 to downregulate CDH1 and partially derepresses CDH1. Chromatin immunoprecipitation assays demonstrated that Snail1 increases the binding of Suz12 to the CDH1 promoter and the trimethylation of lysine 27 in histone H3. Moreover, Snail1 interacts with Suz12 and Ezh2, as shown by coimmunoprecipitation experiments. In conclusion, these results demonstrate that Snail1 recruits PRC2 to the CDH1 promoter and requires the activity of this complex to repress E-cadherin expression.
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