1
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Anyetei-Anum CS, Leatham-Jensen MP, Fox GC, Smith BR, Krajewski K, Strahl BD, Dowen JM, Matera AG, Duronio RJ, McKay DJ. Dual roles of histone H3 lysine-4 in antagonizing Polycomb group function and promoting target gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600669. [PMID: 38979215 PMCID: PMC11230394 DOI: 10.1101/2024.06.25.600669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Tight control over cell identity gene expression is necessary for proper adult form and function. The opposing activities of Polycomb and trithorax complexes determine the ON/OFF state of targets like the Hox genes. Trithorax encodes a methyltransferase specific to histone H3 lysine-4 (H3K4). However, there is no direct evidence that H3K4 regulates Polycomb group target genes in vivo . Here, we demonstrate two key roles for replication-dependent histone H3.2K4 in target control. We find that H3.2K4 antagonizes Polycomb group catalytic activity and that it is required for proper target gene activation. We conclude that H3.2K4 directly regulates expression of Polycomb targets.
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2
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Parreno V, Loubiere V, Schuettengruber B, Fritsch L, Rawal CC, Erokhin M, Győrffy B, Normanno D, Di Stefano M, Moreaux J, Butova NL, Chiolo I, Chetverina D, Martinez AM, Cavalli G. Transient loss of Polycomb components induces an epigenetic cancer fate. Nature 2024; 629:688-696. [PMID: 38658752 PMCID: PMC11096130 DOI: 10.1038/s41586-024-07328-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/15/2024] [Indexed: 04/26/2024]
Abstract
Although cancer initiation and progression are generally associated with the accumulation of somatic mutations1,2, substantial epigenomic alterations underlie many aspects of tumorigenesis and cancer susceptibility3-6, suggesting that genetic mechanisms might not be the only drivers of malignant transformation7. However, whether purely non-genetic mechanisms are sufficient to initiate tumorigenesis irrespective of mutations has been unknown. Here, we show that a transient perturbation of transcriptional silencing mediated by Polycomb group proteins is sufficient to induce an irreversible switch to a cancer cell fate in Drosophila. This is linked to the irreversible derepression of genes that can drive tumorigenesis, including members of the JAK-STAT signalling pathway and zfh1, the fly homologue of the ZEB1 oncogene, whose aberrant activation is required for Polycomb perturbation-induced tumorigenesis. These data show that a reversible depletion of Polycomb proteins can induce cancer in the absence of driver mutations, suggesting that tumours can emerge through epigenetic dysregulation leading to inheritance of altered cell fates.
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Affiliation(s)
- V Parreno
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - V Loubiere
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - B Schuettengruber
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - L Fritsch
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - C C Rawal
- University of Southern California, Los Angeles, CA, USA
| | - M Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - B Győrffy
- Semmelweis University Department of Bioinformatics, Budapest, Hungary
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - D Normanno
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - M Di Stefano
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
| | - J Moreaux
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France
- Department of Biological Hematology, CHU Montpellier, Montpellier, France
- UFR Medicine, University of Montpellier, Montpellier, France
| | - N L Butova
- University of Southern California, Los Angeles, CA, USA
| | - I Chiolo
- University of Southern California, Los Angeles, CA, USA
| | - D Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - A-M Martinez
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France.
| | - G Cavalli
- Institute of Human Genetics, CNRS, University of Montpellier, Montpellier, France.
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3
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Fischer F, Ernst L, Frey A, Holstein K, Prasad D, Weichselberger V, Balaji R, Classen AK. A mismatch in the expression of cell surface molecules induces tissue-intrinsic defense against aberrant cells. Curr Biol 2024; 34:980-996.e6. [PMID: 38350446 DOI: 10.1016/j.cub.2024.01.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/29/2023] [Accepted: 01/19/2024] [Indexed: 02/15/2024]
Abstract
Tissue-intrinsic error correction enables epithelial cells to detect abnormal neighboring cells and facilitate their removal from the tissue. One of these pathways, "interface surveillance," is triggered by cells with aberrant developmental and cell-fate-patterning pathways. It remains unknown which molecular mechanisms provide cells with the ability to compare fate between neighboring cells. We demonstrate that Drosophila imaginal discs express an array of cell surface molecules previously implicated in neuronal axon guidance processes. They include members of the Robo, Teneurin, Ephrin, Toll-like, or atypical cadherin families. Importantly, a mismatch in expression levels of these cell surface molecules between adjacent cells is sufficient to induce interface surveillance, indicating that differences in expression levels between neighboring cells, rather than their absolute expression levels, are crucial. Specifically, a mismatch in Robo2 and Robo3, but not Robo1, induces enrichment of actin, myosin II, and Ena/Vasp, as well as activation of JNK and apoptosis at clonal interfaces. Moreover, Robo2 can induce interface surveillance independently of its cytosolic domain and without the need for the Robo-ligand Slit. The expression of Robo2 and other cell surface molecules, such as Teneurins or the Ephrin receptor is regulated by fate-patterning pathways intrinsic and extrinsic to the wing disc, as well as by expression of oncogenic RasV12. Combined, we demonstrate that neighboring cells respond to a mismatch in surface code patterns mediated by specific transmembrane proteins and reveal a novel function for these cell surface proteins in cell fate recognition and removal of aberrant cells during development and homeostasis of epithelial tissues.
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Affiliation(s)
- Friedericke Fischer
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Immunobiology, Epigenetics, and Metabolism, 79108 Freiburg, Germany
| | - Laurin Ernst
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Immunobiology, Epigenetics, and Metabolism, 79108 Freiburg, Germany
| | - Anna Frey
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
| | - Katrin Holstein
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Deepti Prasad
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
| | - Vanessa Weichselberger
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany; Aix Marseille University, CNRS, UMR 7288, IBDM, 13288 Marseille, France
| | - Ramya Balaji
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Anne-Kathrin Classen
- Hilde-Mangold-Haus, University of Freiburg, 79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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4
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Espinosa-Martínez M, Alcázar-Fabra M, Landeira D. The molecular basis of cell memory in mammals: The epigenetic cycle. SCIENCE ADVANCES 2024; 10:eadl3188. [PMID: 38416817 PMCID: PMC10901381 DOI: 10.1126/sciadv.adl3188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/26/2024] [Indexed: 03/01/2024]
Abstract
Cell memory refers to the capacity of cells to maintain their gene expression program once the initiating environmental signal has ceased. This exceptional feature is key during the formation of mammalian organisms, and it is believed to be in part mediated by epigenetic factors that can endorse cells with the landmarks required to maintain transcriptional programs upon cell duplication. Here, we review current literature analyzing the molecular basis of epigenetic memory in mammals, with a focus on the mechanisms by which transcriptionally repressive chromatin modifications such as methylation of DNA and histone H3 are propagated through mitotic cell divisions. The emerging picture suggests that cellular memory is supported by an epigenetic cycle in which reversible activities carried out by epigenetic regulators in coordination with cell cycle transition create a multiphasic system that can accommodate both maintenance of cell identity and cell differentiation in proliferating stem cell populations.
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Affiliation(s)
- Mencía Espinosa-Martínez
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - María Alcázar-Fabra
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - David Landeira
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
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5
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Seif E, Francis NJ. A Two-Step Mechanism for Creating Stable, Condensed Chromatin with the Polycomb Complex PRC1. Molecules 2024; 29:323. [PMID: 38257239 PMCID: PMC10821450 DOI: 10.3390/molecules29020323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
The Drosophila PRC1 complex regulates gene expression by modifying histone proteins and chromatin architecture. Two PRC1 subunits, PSC and Ph, are most implicated in chromatin architecture. In vitro, PRC1 compacts chromatin and inhibits transcription and nucleosome remodeling. The long disordered C-terminal region of PSC (PSC-CTR) is important for these activities, while Ph has little effect. In cells, Ph is important for condensate formation, long-range chromatin interactions, and gene regulation, and its polymerizing sterile alpha motif (SAM) is implicated in these activities. In vitro, truncated Ph containing the SAM and two other conserved domains (mini-Ph) undergoes phase separation with chromatin, suggesting a mechanism for SAM-dependent condensate formation in vivo. How the distinct activities of PSC and Ph on chromatin function together in PRC1 is not known. To address this question, we analyzed structures formed with large chromatin templates and PRC1 in vitro. PRC1 bridges chromatin into extensive fibrillar networks. Ph, its SAM, and SAM polymerization activity have little effect on these structures. Instead, the PSC-CTR controls their growth, and is sufficient for their formation. To understand how phase separation driven by Ph SAM intersects with the chromatin bridging activity of the PSC-CTR, we used mini-Ph to form condensates with chromatin and then challenged them with PRC1 lacking Ph (PRC1ΔPh). PRC1ΔPh converts mini-Ph chromatin condensates into clusters of small non-fusing condensates and bridged fibers. These condensates retain a high level of chromatin compaction and do not intermix. Thus, phase separation of chromatin by mini-Ph, followed by the action of the PSC-CTR, creates a unique chromatin organization with regions of high nucleosome density and extraordinary stability. We discuss how this coordinated sequential activity of two proteins found in the same complex may occur and the possible implications of stable chromatin architectures in maintaining transcription states.
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Affiliation(s)
- Elias Seif
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
| | - Nicole J. Francis
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada;
- Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montréal, QC H4A 3J1, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, QC H3T 1J4, Canada
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6
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Bu S, Lau SSY, Yong WL, Zhang H, Thiagarajan S, Bashirullah A, Yu F. Polycomb group genes are required for neuronal pruning in Drosophila. BMC Biol 2023; 21:33. [PMID: 36793038 PMCID: PMC9933400 DOI: 10.1186/s12915-023-01534-0] [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: 09/15/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Pruning that selectively eliminates unnecessary or incorrect neurites is required for proper wiring of the mature nervous system. During Drosophila metamorphosis, dendritic arbourization sensory neurons (ddaCs) and mushroom body (MB) γ neurons can selectively prune their larval dendrites and/or axons in response to the steroid hormone ecdysone. An ecdysone-induced transcriptional cascade plays a key role in initiating neuronal pruning. However, how downstream components of ecdysone signalling are induced remains not entirely understood. RESULTS Here, we identify that Scm, a component of Polycomb group (PcG) complexes, is required for dendrite pruning of ddaC neurons. We show that two PcG complexes, PRC1 and PRC2, are important for dendrite pruning. Interestingly, depletion of PRC1 strongly enhances ectopic expression of Abdominal B (Abd-B) and Sex combs reduced, whereas loss of PRC2 causes mild upregulation of Ultrabithorax and Abdominal A in ddaC neurons. Among these Hox genes, overexpression of Abd-B causes the most severe pruning defects, suggesting its dominant effect. Knockdown of the core PRC1 component Polyhomeotic (Ph) or Abd-B overexpression selectively downregulates Mical expression, thereby inhibiting ecdysone signalling. Finally, Ph is also required for axon pruning and Abd-B silencing in MB γ neurons, indicating a conserved function of PRC1 in two types of pruning. CONCLUSIONS This study demonstrates important roles of PcG and Hox genes in regulating ecdysone signalling and neuronal pruning in Drosophila. Moreover, our findings suggest a non-canonical and PRC2-independent role of PRC1 in Hox gene silencing during neuronal pruning.
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Affiliation(s)
- Shufeng Bu
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore ,grid.4280.e0000 0001 2180 6431Department of Biological Sciences, National University of Singapore, Singapore, 117543 Singapore
| | - Samuel Song Yuan Lau
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Wei Lin Yong
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Heng Zhang
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore
| | - Sasinthiran Thiagarajan
- grid.4280.e0000 0001 2180 6431Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604 Singapore ,grid.4280.e0000 0001 2180 6431Department of Biological Sciences, National University of Singapore, Singapore, 117543 Singapore
| | - Arash Bashirullah
- grid.14003.360000 0001 2167 3675Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222 USA
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore. .,Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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7
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Prasad D, Illek K, Fischer F, Holstein K, Classen AK. Bilateral JNK activation is a hallmark of interface surveillance and promotes elimination of aberrant cells. eLife 2023; 12:e80809. [PMID: 36744859 PMCID: PMC9917460 DOI: 10.7554/elife.80809] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 02/03/2023] [Indexed: 02/07/2023] Open
Abstract
Tissue-intrinsic defense mechanisms eliminate aberrant cells from epithelia and thereby maintain the health of developing tissues or adult organisms. 'Interface surveillance' comprises one such distinct mechanism that specifically guards against aberrant cells which undergo inappropriate cell fate and differentiation programs. The cellular mechanisms which facilitate detection and elimination of these aberrant cells are currently unknown. We find that in Drosophila imaginal discs, clones of cells with inappropriate activation of cell fate programs induce bilateral JNK activation at clonal interfaces, where wild type and aberrant cells make contact. JNK activation is required to drive apoptotic elimination of interface cells. Importantly, JNK activity and apoptosis are highest in interface cells within small aberrant clones, which likely supports the successful elimination of aberrant cells when they arise. Our findings are consistent with a model where clone size affects the topology of interface contacts and thereby the strength of JNK activation in wild type and aberrant interface cells. Bilateral JNK activation is unique to 'interface surveillance' and is not observed in other tissue-intrinsic defense mechanisms, such as classical 'cell-cell competition'. Thus, bilateral JNK interface signaling provides an independent tissue-level mechanism to eliminate cells with inappropriate developmental fate but normal cellular fitness. Finally, oncogenic Ras-expressing clones activate 'interface surveillance' but evade elimination by bilateral JNK activation. Combined, our work establishes bilateral JNK interface signaling and interface apoptosis as a new hallmark of interface surveillance and highlights how oncogenic mutations evade tumor suppressor function encoded by this tissue-intrinsic surveillance system.
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Affiliation(s)
- Deepti Prasad
- Hilde-Mangold-Haus, University of FreiburgFreiburgGermany
- Spemann Graduate School of Biology and Medicine (SGBM), University of FreiburgFreiburgGermany
- Faculty of Biology, University of FreiburgFreiburgGermany
| | | | - Friedericke Fischer
- Hilde-Mangold-Haus, University of FreiburgFreiburgGermany
- Faculty of Biology, University of FreiburgFreiburgGermany
- International Max Planck Research School for Immunobiology, Epigenetics, and MetabolismFreiburgGermany
| | | | - Anne-Kathrin Classen
- Hilde-Mangold-Haus, University of FreiburgFreiburgGermany
- Faculty of Biology, University of FreiburgFreiburgGermany
- CIBSS Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
- BIOSS Centre for Biological Signalling Studies, University of FreiburgFreiburgGermany
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8
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Abstract
Polycomb group (PcG) proteins are crucial chromatin regulators that maintain repression of lineage-inappropriate genes and are therefore required for stable cell fate. Recent advances show that PcG proteins form distinct multi-protein complexes in various cellular environments, such as in early development, adult tissue maintenance and cancer. This surprising compositional diversity provides the basis for mechanistic diversity. Understanding this complexity deepens and refines the principles of PcG complex recruitment, target-gene repression and inheritance of memory. We review how the core molecular mechanism of Polycomb complexes operates in diverse developmental settings and propose that context-dependent changes in composition and mechanism are essential for proper epigenetic regulation in development.
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Affiliation(s)
- Jongmin J Kim
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Robert E Kingston
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
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9
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Kang H, Cabrera JR, Zee BM, Kang HA, Jobe JM, Hegarty MB, Barry AE, Glotov A, Schwartz YB, Kuroda MI. Variant Polycomb complexes in Drosophila consistent with ancient functional diversity. SCIENCE ADVANCES 2022; 8:eadd0103. [PMID: 36070387 PMCID: PMC9451159 DOI: 10.1126/sciadv.add0103] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Polycomb group (PcG) mutants were first identified in Drosophila on the basis of their failure to maintain proper Hox gene repression during development. The proteins encoded by the corresponding fly genes mainly assemble into one of two discrete Polycomb repressive complexes: PRC1 or PRC2. However, biochemical analyses in mammals have revealed alternative forms of PRC2 and multiple distinct types of noncanonical or variant PRC1. Through a series of proteomic analyses, we identify analogous PRC2 and variant PRC1 complexes in Drosophila, as well as a broader repertoire of interactions implicated in early development. Our data provide strong support for the ancient diversity of PcG complexes and a framework for future analysis in a longstanding and versatile genetic system.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Janel R. Cabrera
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- Biology Department, Emmanuel College, Boston, MA 02115, USA
| | - Barry M. Zee
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Heather A. Kang
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | - Alexander Glotov
- Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
| | - Yuri B. Schwartz
- Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
| | - Mitzi I. Kuroda
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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10
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Cheng Q, Xie H, Zhang X, Wang M, Bi C, Wang Q, Wang R, Fang M. An essential role for
PTIP
in mediating Hox gene regulation along
PcG
and
trxG
pathways. FEBS J 2022; 289:6324-6341. [DOI: 10.1111/febs.16541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/19/2022] [Accepted: 05/31/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Qian Cheng
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
| | - Hao Xie
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
| | - Xiao‐Yan Zhang
- Department of Genetic Medicine Johns Hopkins University School of Medicine Baltimore MD USA
| | - Ming‐Ying Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
| | - Cai‐Li Bi
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
- Institute of Translational Medicine, Medical College Yangzhou University China
| | - Qiang Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
| | - Rui Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
| | - Ming Fang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases Southeast University Nanjing China
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11
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Delker RK, Munce RH, Hu M, Mann RS. Fluorescent labeling of genomic loci in Drosophila imaginal discs with heterologous DNA-binding proteins. CELL REPORTS METHODS 2022; 2:100175. [PMID: 35475221 PMCID: PMC9017127 DOI: 10.1016/j.crmeth.2022.100175] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/02/2021] [Accepted: 02/11/2022] [Indexed: 11/25/2022]
Abstract
Using the Drosophila melanogaster Hox gene Ultrabithorax (Ubx) as an example, we demonstrate the use of three heterologous DNA-binding protein systems-LacI/LacO, ParB1/ParS1, and ParB2/ParS2-to label genomic loci in imaginal discs with the insertion of a small DNA tag. We compare each system, considering the impact of labeling in genomic regions (1) inside versus outside of a transcribed gene body and (2) with varying chromatin accessibility. We demonstrate the value of this system by interrogating the relationship between gene expression level and enhancer-promoter distance, as well as inter-allelic distance at the Ubx locus. We find that the distance between an essential intronic cis-regulatory element, anterobithorax (abx), and the promoter does not vary with expression level. In contrast, inter-allelic distance correlates with Ubx expression level.
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Affiliation(s)
- Rebecca K. Delker
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Ross H. Munce
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Michelle Hu
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Neuroscience, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
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12
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Hafer TL, Patra S, Tagami D, Kohwi M. Enhancer of trithorax/polycomb, Corto, regulates timing of hunchback gene relocation and competence in Drosophila neuroblasts. Neural Dev 2022; 17:3. [PMID: 35177098 PMCID: PMC8855600 DOI: 10.1186/s13064-022-00159-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/27/2022] [Indexed: 12/27/2022] Open
Abstract
Background Neural progenitors produce diverse cells in a stereotyped birth order, but can specify each cell type for only a limited duration. In the Drosophila embryo, neuroblasts (neural progenitors) specify multiple, distinct neurons by sequentially expressing a series of temporal identity transcription factors with each division. Hunchback (Hb), the first of the series, specifies early-born neuronal identity. Neuroblast competence to generate early-born neurons is terminated when the hb gene relocates to the neuroblast nuclear lamina, rendering it refractory to activation in descendent neurons. Mechanisms and trans-acting factors underlying this process are poorly understood. Here we identify Corto, an enhancer of Trithorax/Polycomb (ETP) protein, as a new regulator of neuroblast competence. Methods We used the GAL4/UAS system to drive persistent misexpression of Hb in neuroblast 7–1 (NB7-1), a model lineage for which the early competence window has been well characterized, to examine the role of Corto in neuroblast competence. We used immuno-DNA Fluorescence in situ hybridization (DNA FISH) in whole embryos to track the position of the hb gene locus specifically in neuroblasts across developmental time, comparing corto mutants to control embryos. Finally, we used immunostaining in whole embryos to examine Corto’s role in repression of Hb and a known target gene, Abdominal B (Abd-B). Results We found that in corto mutants, the hb gene relocation to the neuroblast nuclear lamina is delayed and the early competence window is extended. The delay in gene relocation occurs after hb transcription is already terminated in the neuroblast and is not due to prolonged transcriptional activity. Further, we find that Corto genetically interacts with Posterior Sex Combs (Psc), a core subunit of polycomb group complex 1 (PRC1), to terminate early competence. Loss of Corto does not result in derepression of Hb or its Hox target, Abd-B, specifically in neuroblasts. Conclusions These results show that in neuroblasts, Corto genetically interacts with PRC1 to regulate timing of nuclear architecture reorganization and support the model that distinct mechanisms of silencing are implemented in a step-wise fashion during development to regulate cell fate gene expression in neuronal progeny. Supplementary Information The online version contains supplementary material available at 10.1186/s13064-022-00159-3.
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Affiliation(s)
- Terry L Hafer
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA.,Present Address: Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98195, USA
| | - Sofiya Patra
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA
| | - Daiki Tagami
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA
| | - Minoree Kohwi
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA. .,Kavli Institute for Brain Science, Columbia University, New York, NY, 10027, USA.
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13
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Kinsey SD, Vinluan JP, Shipman GA, Verheyen EM. Expression of human HIPKs in Drosophila demonstrates their shared and unique functions in a developmental model. G3 GENES|GENOMES|GENETICS 2021; 11:6380948. [PMID: 34849772 PMCID: PMC8673556 DOI: 10.1093/g3journal/jkab350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/21/2021] [Indexed: 12/27/2022]
Abstract
Homeodomain-interacting protein kinases (HIPKs) are a family of four conserved proteins essential for vertebrate development, as demonstrated by defects in the eye, brain, and skeleton that culminate in embryonic lethality when multiple HIPKs are lost in mice. While HIPKs are essential for development, functional redundancy between the four vertebrate HIPK paralogues has made it difficult to compare their respective functions. Because understanding the unique and shared functions of these essential proteins could directly benefit the fields of biology and medicine, we addressed the gap in knowledge of the four vertebrate HIPK paralogues by studying them in the fruit fly Drosophila melanogaster, where reduced genetic redundancy simplifies our functional assessment. The single hipk present in the fly allowed us to perform rescue experiments with human HIPK genes that provide new insight into their individual functions not easily assessed in vertebrate models. Furthermore, the abundance of genetic tools and established methods for monitoring specific developmental pathways and gross morphological changes in the fly allowed for functional comparisons in endogenous contexts. We first performed rescue experiments to demonstrate the extent to which each of the human HIPKs can functionally replace Drosophila Hipk for survival and morphological development. We then showed the ability of each human HIPK to modulate Armadillo/β-catenin levels, JAK/STAT activity, proliferation, growth, and death, each of which have previously been described for Hipks, but never all together in comparable tissue contexts. Finally, we characterized novel developmental phenotypes induced by human HIPKs to gain insight to their unique functions. Together, these experiments provide the first direct comparison of all four vertebrate HIPKs to determine their roles in a developmental context.
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Affiliation(s)
- Stephen D Kinsey
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Justin P Vinluan
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Gerald A Shipman
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Esther M Verheyen
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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14
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Holoch D, Wassef M, Lövkvist C, Zielinski D, Aflaki S, Lombard B, Héry T, Loew D, Howard M, Margueron R. A cis-acting mechanism mediates transcriptional memory at Polycomb target genes in mammals. Nat Genet 2021; 53:1686-1697. [PMID: 34782763 DOI: 10.1038/s41588-021-00964-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/05/2021] [Indexed: 11/09/2022]
Abstract
Epigenetic inheritance of gene expression states enables a single genome to maintain distinct cellular identities. How histone modifications contribute to this process remains unclear. Using global chromatin perturbations and local, time-controlled modulation of transcription, we establish the existence of epigenetic memory of transcriptional activation for genes that can be silenced by the Polycomb group. This property emerges during cell differentiation and allows genes to be stably switched after a transient transcriptional stimulus. This transcriptional memory state at Polycomb targets operates in cis; however, rather than relying solely on read-and-write propagation of histone modifications, the memory is also linked to the strength of activating inputs opposing Polycomb proteins, and therefore varies with the cellular context. Our data and computational simulations suggest a model whereby transcriptional memory arises from double-negative feedback between Polycomb-mediated silencing and active transcription. Transcriptional memory at Polycomb targets thus depends not only on histone modifications but also on the gene-regulatory network and underlying identity of a cell.
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Affiliation(s)
- Daniel Holoch
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,INSERM U934/CNRS UMR 3215, Paris, France
| | - Michel Wassef
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,INSERM U934/CNRS UMR 3215, Paris, France
| | - Cecilia Lövkvist
- John Innes Centre, Norwich Research Park, Norwich, UK. .,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark.
| | - Dina Zielinski
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,INSERM U934/CNRS UMR 3215, Paris, France.,INSERM U900, Mines ParisTech, Paris, France
| | - Setareh Aflaki
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,INSERM U934/CNRS UMR 3215, Paris, France
| | - Bérangère Lombard
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,Proteomics Mass Spectrometry Laboratory, Paris, France
| | - Tiphaine Héry
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,INSERM U934/CNRS UMR 3215, Paris, France
| | - Damarys Loew
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France.,Proteomics Mass Spectrometry Laboratory, Paris, France
| | - Martin Howard
- John Innes Centre, Norwich Research Park, Norwich, UK
| | - Raphaël Margueron
- Institut Curie, Paris Sciences et Lettres Research University, Sorbonne University, Paris, France. .,INSERM U934/CNRS UMR 3215, Paris, France.
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15
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Tumorigenesis and cell competition in Drosophila in the absence of polyhomeotic function. Proc Natl Acad Sci U S A 2021; 118:2110062118. [PMID: 34702735 DOI: 10.1073/pnas.2110062118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 12/12/2022] Open
Abstract
Cell competition is a homeostatic process that eliminates by apoptosis unfit or undesirable cells from animal tissues, including tumor cells that appear during the life of the organism. In Drosophila there is evidence that many types of oncogenic cells are eliminated by cell competition. One exception is cells mutant for polyhomeotic (ph), a member of the Polycomb family of genes; most of the isolated mutant ph clones survive and develop tumorous overgrowths in imaginal discs. To characterize the tumorigenic effect of the lack of ph, we first studied the growth of different regions of the wing disc deficient in ph activity and found that the effect is restricted to the proximal appendage. Moreover, we found that ph-deficient tissue is partially refractory to apoptosis. Second, we analyzed the behavior of clones lacking ph function and found that many suffer cell competition but are not completely eliminated. Unexpectedly, we found that nonmutant cells also undergo cell competition when surrounded by ph-deficient cells, indicating that within the same tissue cell competition may operate in opposite directions. We suggest two reasons for the incompleteness of cell competition in ph mutant cells: 1) These cells are partially refractory to apoptosis, and 2) the loss of ph function alters the identity of imaginal cells and subsequently their cell affinities. It compromises the winner/loser interaction, a prerequisite for cell competition.
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16
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Singkaravanit-Ogawa S, Kosaka A, Kitakura S, Uchida K, Nishiuchi T, Ono E, Fukunaga S, Takano Y. Arabidopsis CURLY LEAF functions in leaf immunity against fungal pathogens by concomitantly repressing SEPALLATA3 and activating ORA59. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1005-1019. [PMID: 34506685 DOI: 10.1111/tpj.15488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
Arabidopsis non-host resistance against non-adapted fungal pathogens including Colletotrichum fungi consists of pre-invasive and post-invasive immune responses. Here we report that non-host resistance against non-adapted Colletotrichum spp. in Arabidopsis leaves requires CURLY LEAF (CLF), which is critical for leaf development, flowering and growth. Microscopic analysis of pathogen behavior revealed a requirement for CLF in both pre- and post-invasive non-host resistance. The loss of a functional SEPALLATA3 (SEP3) gene, ectopically expressed in clf mutant leaves, suppressed not only the defect of the clf plants in growth and leaf development but also a defect in non-host resistance against the non-adapted Colletotrichum tropicale. However, the ectopic overexpression of SEP3 in Arabidopsis wild-type leaves did not disrupt the non-host resistance. The expression of multiple plant defensin (PDF) genes that are involved in non-host resistance against C. tropicale was repressed in clf leaves. Moreover, the Octadecanoid-responsive Arabidopsis 59 (ORA59) gene, which is required for PDF expression, was also repressed in clf leaves. Notably, when SEP3 was overexpressed in the ora59 mutant background, C. tropicale produced clear lesions in the inoculated leaves, indicating an impairment in non-host resistance. Furthermore, ora59 plants overexpressing SEP3 exhibited a defect in leaf immunity to the adapted Colletotrichum higginsianum. Since the ora59 plants overexpressing SEP3 did not display obvious leaf curling or reduced growth, in contrast to the clf mutants, these results strongly suggest that concomitant SEP3 repression and ORA59 induction via CLF are required for Arabidopsis leaf immunity to Colletotrichum fungi, uncoupled from CLF's function in growth and leaf development.
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Affiliation(s)
| | - Ayumi Kosaka
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Saeko Kitakura
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Kotaro Uchida
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Takumi Nishiuchi
- Advanced Science Research Center, Institute for Gene Research, Kanazawa University, Ishikawa, Japan
| | - Erika Ono
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Satoshi Fukunaga
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Yoshitaka Takano
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
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17
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Shaheen N, Akhtar J, Umer Z, Khan MHF, Bakhtiari MH, Saleem M, Faisal A, Tariq M. Polycomb Requires Chaperonin Containing TCP-1 Subunit 7 for Maintaining Gene Silencing in Drosophila. Front Cell Dev Biol 2021; 9:727972. [PMID: 34660585 PMCID: PMC8517254 DOI: 10.3389/fcell.2021.727972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
In metazoans, heritable states of cell type-specific gene expression patterns linked with specialization of various cell types constitute transcriptional cellular memory. Evolutionarily conserved Polycomb group (PcG) and trithorax group (trxG) proteins contribute to the transcriptional cellular memory by maintaining heritable patterns of repressed and active expression states, respectively. Although chromatin structure and modifications appear to play a fundamental role in maintenance of repression by PcG, the precise targeting mechanism and the specificity factors that bind PcG complexes to defined regions in chromosomes remain elusive. Here, we report a serendipitous discovery that uncovers an interplay between Polycomb (Pc) and chaperonin containing T-complex protein 1 (TCP-1) subunit 7 (CCT7) of TCP-1 ring complex (TRiC) chaperonin in Drosophila. CCT7 interacts with Pc at chromatin to maintain repressed states of homeotic and non-homeotic targets of PcG, which supports a strong genetic interaction observed between Pc and CCT7 mutants. Depletion of CCT7 results in dissociation of Pc from chromatin and redistribution of an abundant amount of Pc in cytoplasm. We propose that CCT7 is an important modulator of Pc, which helps Pc recruitment at chromatin, and compromising CCT7 can directly influence an evolutionary conserved epigenetic network that supervises the appropriate cellular identities during development and homeostasis of an organism.
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Affiliation(s)
- Najma Shaheen
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Jawad Akhtar
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Zain Umer
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Haider Farooq Khan
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Mahnoor Hussain Bakhtiari
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Murtaza Saleem
- Department of Physics, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Amir Faisal
- Cancer Therapeutics Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Tariq
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
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18
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Shaukat A, Khan MHF, Ahmad H, Umer Z, Tariq M. Interplay Between BALL and CREB Binding Protein Maintains H3K27 Acetylation on Active Genes in Drosophila. Front Cell Dev Biol 2021; 9:740866. [PMID: 34650987 PMCID: PMC8509297 DOI: 10.3389/fcell.2021.740866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/07/2021] [Indexed: 12/22/2022] Open
Abstract
CREB binding protein (CBP) is a multifunctional transcriptional co-activator that interacts with a variety of transcription factors and acts as a histone acetyltransferase. In Drosophila, CBP mediated acetylation of histone H3 lysine 27 (H3K27ac) is a known hallmark of gene activation regulated by trithorax group proteins (trxG). Recently, we have shown that a histone kinase Ballchen (BALL) substantially co-localizes with H3K27ac at trxG target loci and is required to maintain gene activation in Drosophila. Here, we report a previously unknown interaction between BALL and CBP, which positively regulates H3K27ac. Analysis of genome-wide binding profile of BALL and CBP reveals major overlap and their co-localization at actively transcribed genes. We show that BALL biochemically interacts with CBP and depletion of BALL results in drastic reduction in H3K27ac. Together, these results demonstrate a previously unknown synergy between BALL and CBP and reveals a potentially new pathway required to maintain gene activation during development.
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Affiliation(s)
- Ammad Shaukat
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Haider Farooq Khan
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Hina Ahmad
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Zain Umer
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Tariq
- Epigenetics and Gene Regulation Laboratory, Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
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19
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Lucas T, Hafer TL, Zhang HG, Molotkova N, Kohwi M. Discrete cis-acting element regulates developmentally timed gene-lamina relocation and neural progenitor competence in vivo. Dev Cell 2021; 56:2649-2663.e6. [PMID: 34529940 PMCID: PMC8629127 DOI: 10.1016/j.devcel.2021.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/24/2021] [Accepted: 08/20/2021] [Indexed: 01/21/2023]
Abstract
The nuclear lamina is typically associated with transcriptional silencing, and peripheral relocation of genes highly correlates with repression. However, the DNA sequences and proteins regulating gene-lamina interactions are largely unknown. Exploiting the developmentally timed hunchback gene movement to the lamina in Drosophila neuroblasts, we identified a 250 bp intronic element (IE) both necessary and sufficient for relocation. The IE can target a reporter transgene to the lamina and silence it. Endogenously, however, hunchback is already repressed prior to relocation. Instead, IE-mediated relocation confers a heritably silenced gene state refractory to activation in descendent neurons, which terminates neuroblast competence to specify early-born identity. Surprisingly, we found that the Polycomb group chromatin factors bind the IE and are required for lamina relocation, revealing a nuclear architectural role distinct from their well-known function in transcriptional repression. Together, our results uncover in vivo mechanisms underlying neuroblast competence and lamina association in heritable gene silencing. In Drosophila neuroblasts, relocation of the hunchback gene locus to the nuclear lamina confers heritable silencing in daughter neurons. Lucas et al. identify a genomic element necessary and sufficient for hunchback gene movement in vivo. Polycomb proteins target this element for lamina relocation, thereby regulating competence, but not hunchback expression.
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Affiliation(s)
- Tanguy Lucas
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Terry L Hafer
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Harrison G Zhang
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Natalia Molotkova
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Minoree Kohwi
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
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20
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Elizarev P, Finkl K, Müller J. Distinct requirements for Pho, Sfmbt, and Ino80 for cell survival in Drosophila. Genetics 2021; 219:iyab096. [PMID: 34849913 PMCID: PMC8633127 DOI: 10.1093/genetics/iyab096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/09/2021] [Indexed: 11/25/2022] Open
Abstract
The Drosophila proteins Pleiohomeotic (Pho) and its paralog Pho-like (Phol) are the homologs of the mammalian transcription factor YY1. Pho and Phol are subunits of the Polycomb group protein complex PhoRC and they are also stably associated with the INO80 nucleosome remodeling complex. Drosophila lacking both Pho and Phol arrest development as larvae with small misshaped imaginal discs. The basis of this phenotype is poorly understood. We find that in pho phol mutant animals cells retain the capacity to proliferate but show a high incidence of apoptotic cell death that results in tissue hypoplasia. Clonal analyses establish that cells stringently require Pho and Phol to survive. In contrast, the PhoRC subunit Sfmbt and the ATP-dependent nucleosome remodeling factor Ino80 are not essential for cell viability. Pho and Phol, therefore, execute their critical role for cell survival through mechanisms that do not involve Sfmbt function or INO80 nucleosome remodeling.
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Affiliation(s)
- Pavel Elizarev
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Katja Finkl
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Jürg Müller
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, Martinsried 82152, Germany
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21
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Lefeivre T, Jones L, Trinquand A, Pinton A, Macintyre E, Laurenti E, Bond J. Immature acute leukaemias: lessons from the haematopoietic roadmap. FEBS J 2021; 289:4355-4370. [PMID: 34028982 DOI: 10.1111/febs.16030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/30/2021] [Accepted: 05/20/2021] [Indexed: 11/29/2022]
Abstract
It is essential to relate the biology of acute leukaemia to normal blood cell development. In this review, we discuss how modern models of haematopoiesis might inform approaches to diagnosis and management of immature leukaemias, with a specific focus on T-lymphoid and myeloid cases. In particular, we consider whether next-generation analytical tools could provide new perspectives that could improve our understanding of immature blood cancer biology.
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Affiliation(s)
- Thomas Lefeivre
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin, Ireland.,National Children's Research Centre, Dublin, Ireland
| | - Luke Jones
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin, Ireland.,National Children's Research Centre, Dublin, Ireland
| | - Amélie Trinquand
- National Children's Research Centre, Dublin, Ireland.,Children's Health Ireland at Crumlin, Dublin, Ireland
| | - Antoine Pinton
- Laboratory of Onco-Haematology, Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Necker Enfants-Malades, Université de Paris, Paris, France.,Institut Necker-Enfants Malades (INEM), Institut national de la santé et de la recherche médicale (Inserm) U1151, Paris, France
| | - Elizabeth Macintyre
- Laboratory of Onco-Haematology, Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Necker Enfants-Malades, Université de Paris, Paris, France.,Institut Necker-Enfants Malades (INEM), Institut national de la santé et de la recherche médicale (Inserm) U1151, Paris, France
| | - Elisa Laurenti
- Department of Haematology, University of Cambridge, Cambridge, UK.,Wellcome and MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Jonathan Bond
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin, Ireland.,National Children's Research Centre, Dublin, Ireland.,Children's Health Ireland at Crumlin, Dublin, Ireland
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22
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Parental nucleosome segregation and the inheritance of cellular identity. Nat Rev Genet 2021; 22:379-392. [PMID: 33500558 DOI: 10.1038/s41576-020-00312-w] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2020] [Indexed: 12/20/2022]
Abstract
Gene expression programmes conferring cellular identity are achieved through the organization of chromatin structures that either facilitate or impede transcription. Among the key determinants of chromatin organization are the histone modifications that correlate with a given transcriptional status and chromatin state. Until recently, the details for the segregation of nucleosomes on DNA replication and their implications in re-establishing heritable chromatin domains remained unclear. Here, we review recent findings detailing the local segregation of parental nucleosomes and highlight important advances as to how histone methyltransferases associated with the establishment of repressive chromatin domains facilitate epigenetic inheritance.
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23
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Ninova M, Fejes Tóth K, Aravin AA. The control of gene expression and cell identity by H3K9 trimethylation. Development 2019; 146:dev181180. [PMID: 31540910 PMCID: PMC6803365 DOI: 10.1242/dev.181180] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Histone 3 lysine 9 trimethylation (H3K9me3) is a conserved histone modification that is best known for its role in constitutive heterochromatin formation and the repression of repetitive DNA elements. More recently, it has become evident that H3K9me3 is also deposited at certain loci in a tissue-specific manner and plays important roles in regulating cell identity. Notably, H3K9me3 can repress genes encoding silencing factors, pointing to a fundamental principle of repressive chromatin auto-regulation. Interestingly, recent studies have shown that H3K9me3 deposition requires protein SUMOylation in different contexts, suggesting that the SUMO pathway functions as an important module in gene silencing and heterochromatin formation. In this Review, we discuss the role of H3K9me3 in gene regulation in various systems and the molecular mechanisms that guide the silencing machinery to target loci.
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Affiliation(s)
- Maria Ninova
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Katalin Fejes Tóth
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Alexei A Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
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24
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Abstract
As the process that silences gene expression ensues during development, the stage is set for the activity of Polycomb-repressive complex 2 (PRC2) to maintain these repressed gene profiles. PRC2 catalyzes a specific histone posttranslational modification (hPTM) that fosters chromatin compaction. PRC2 also facilitates the inheritance of this hPTM through its self-contained "write and read" activities, key to preserving cellular identity during cell division. As these changes in gene expression occur without changes in DNA sequence and are inherited, the process is epigenetic in scope. Mutants of mammalian PRC2 or of its histone substrate contribute to the cancer process and other diseases, and research into these aberrant pathways is yielding viable candidates for therapeutic targeting. The effectiveness of PRC2 hinges on its being recruited to the proper chromatin sites; however, resolving the determinants to this process in the mammalian case was not straightforward and thus piqued the interest of many in the field. Here, we chronicle the latest advances toward exposing mammalian PRC2 and its high maintenance.
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Affiliation(s)
- Jia-Ray Yu
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Chul-Hwan Lee
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Ozgur Oksuz
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - James M Stafford
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Danny Reinberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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25
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Asada S, Fujino T, Goyama S, Kitamura T. The role of ASXL1 in hematopoiesis and myeloid malignancies. Cell Mol Life Sci 2019; 76:2511-2523. [PMID: 30927018 PMCID: PMC11105736 DOI: 10.1007/s00018-019-03084-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 03/18/2019] [Accepted: 03/25/2019] [Indexed: 12/19/2022]
Abstract
Recent high-throughput genome-wide sequencing studies have identified recurrent somatic mutations in myeloid neoplasms. An epigenetic regulator, Additional sex combs-like 1 (ASXL1), is one of the most frequently mutated genes in all subtypes of myeloid malignancies. ASXL1 mutations are also frequently detected in clonal hematopoiesis, which is associated with an increased risk of mortality. Therefore, it is important to understand how ASXL1 mutations contribute to clonal expansion and myeloid transformation in hematopoietic cells. Studies using ASXL1-depleted human hematopoietic cells and Asxl1 knockout mice have shown that deletion of wild-type ASXL1 protein leads to impaired hematopoiesis and accelerates myeloid malignancies via loss of interaction with polycomb repressive complex 2 proteins. On the other hand, ASXL1 mutations in myeloid neoplasms typically occur near the last exon and result in the expression of C-terminally truncated mutant ASXL1 protein. Biological studies and biochemical analyses of this variant have shed light on its dominant-negative and gain-of-function features in myeloid transformation via a variety of epigenetic changes. Based on these results, it would be possible to establish novel promising therapeutic strategies for myeloid malignancies harboring ASXL1 mutations by blocking interactions between ASXL1 and associating epigenetic regulators. Here, we summarize the clinical implications of ASXL1 mutations, the role of wild-type ASXL1 in normal hematopoiesis, and oncogenic functions of mutant ASXL1 in myeloid neoplasms.
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Affiliation(s)
- Shuhei Asada
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Takeshi Fujino
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Susumu Goyama
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Advanced Clinical Research Center, and Division of Stem Cell Signaling, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 1088639, Japan.
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26
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Shah M, Funnell APW, Quinlan KGR, Crossley M. Hit and Run Transcriptional Repressors Are Difficult to Catch in the Act. Bioessays 2019; 41:e1900041. [PMID: 31245868 DOI: 10.1002/bies.201900041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/04/2019] [Indexed: 11/11/2022]
Abstract
Transcriptional silencing may not necessarily depend on the continuous residence of a sequence-specific repressor at a control element and may act via a "hit and run" mechanism. Due to limitations in assays that detect transcription factor (TF) binding, such as chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), this phenomenon may be challenging to detect and therefore its prevalence may be underappreciated. To explore this possibility, erythroid gene promoters that are regulated directly by GATA1 in an inducible system are analyzed. It is found that many regulated genes are bound immediately after induction of GATA1 but the residency of GATA1 decreases over time, particularly at repressed genes. Furthermore, it is shown that the repressive mark H3K27me3 is seldom associated with bound repressors, whereas, in contrast, the active (H3K4me3) histone mark is overwhelmingly associated with TF binding. It is hypothesized that during cellular differentiation and development, certain genes are silenced by repressive TFs that subsequently vacate the region. Catching such repressor TFs in the act of silencing via assays such as ChIP-seq is thus a temporally challenging prospect. The use of inducible systems, epitope tags, and alternative techniques may provide opportunities for detecting elusive "hit and run" transcriptional silencing. Also see the video abstract here https://youtu.be/vgrsoP_HF3g.
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Affiliation(s)
- Manan Shah
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Alister P W Funnell
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia.,Altius Institute for Biomedical Sciences, Seattle, WA, 98121, USA
| | - Kate G R Quinlan
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Merlin Crossley
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, 2052, Australia
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27
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United colours of chromatin? Developmental genome organisation in flies. Biochem Soc Trans 2019; 47:691-700. [PMID: 30902925 DOI: 10.1042/bst20180605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 11/17/2022]
Abstract
The organisation of DNA into differing forms of packaging, or chromatin, controls many of the cell fate decisions during development. Although early studies focused on individual forms of chromatin, in the last decade more holistic studies have attempted to determine a complete picture of the different forms of chromatin present within a cell. In the fruit fly, Drosophila melanogaster, the study of chromatin states has been aided by the use of complementary and cell-type-specific techniques that profile the marks that recruit chromatin protein binding or the proteins themselves. Although many questions remain unanswered, a clearer picture of how different chromatin states affect development is now emerging, with more unusual chromatin states such as Black chromatin playing key roles. Here, we discuss recent findings regarding chromatin biology in flies.
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28
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Rosales-Vega M, Hernández-Becerril A, Murillo-Maldonado JM, Zurita M, Vázquez M. The role of the trithorax group TnaA isoforms in Hox gene expression, and in Drosophila late development. PLoS One 2018; 13:e0206587. [PMID: 30372466 PMCID: PMC6205608 DOI: 10.1371/journal.pone.0206587] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/16/2018] [Indexed: 11/18/2022] Open
Abstract
Regulation of developmental gene expression in eukaryotes involves several levels. One of them is the maintenance of gene expression along the life of the animal once it is started by different triggers early in development. One of the questions in the field is when in developmental time, the animal start to use the different maintenance mechanisms. The trithorax group (TrxG) of genes was first characterized as essential for maintaining homeotic gene expression. The TrxG gene tonalli interacts genetically and physically with genes and subunits of the BRAHMA BAP chromatin remodeling complex and encodes TnaA proteins with putative E3 SUMO-ligase activity. In contrast to the phenocritic lethal phase of animals with mutations in other TrxG genes, tna mutant individuals die late in development. In this study we determined the requirements of TnaA for survival at pupal and adult stages, in different tna mutant genotypes where we corroborate the lack of TnaA proteins, and the presence of adult homeotic loss-of-function phenotypes. We also investigated whether the absence of TnaA in haltere and leg larval imaginal discs affects the presence of the homeotic proteins Ultrabithorax and Sex combs reduced respectively by using some of the characterized genotypes and more finely by generating TnaA defective clones induced at different stages of development. We found that, tna is not required for growth or survival of imaginal disc cells and that it is a fine modulator of homeotic gene expression.
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Affiliation(s)
- Marco Rosales-Vega
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Adriana Hernández-Becerril
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Juan Manuel Murillo-Maldonado
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Querétaro, México
| | - Mario Zurita
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Martha Vázquez
- Departamento de Fisiología Molecular y Genética del Desarrollo, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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29
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Kim H, Langohr IM, Faisal M, McNulty M, Thorn C, Kim J. Ablation of Ezh2 in neural crest cells leads to aberrant enteric nervous system development in mice. PLoS One 2018; 13:e0203391. [PMID: 30169530 PMCID: PMC6118393 DOI: 10.1371/journal.pone.0203391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/20/2018] [Indexed: 11/19/2022] Open
Abstract
In the current study, we examined the role of Ezh2 as an epigenetic modifier for the enteric neural crest cell development through H3K27me3. Ezh2 conditional null mice were viable up to birth, but died within the first hour of life. In addition to craniofacial defects, Ezh2 conditional null mice displayed reduced number of ganglion cells in the enteric nervous system. RT-PCR and ChIP assays indicated aberrant up-regulation of Zic1, Pax3, and Sox10 and loss of H3K27me3 marks in the promoter regions of these genes in the myenteric plexus. Overall, these results suggest that Ezh2 is an important epigenetic modifier for the enteric neural crest cell development through repression of Zic1, Pax3, and Sox10.
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Affiliation(s)
- Hana Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Ingeborg M. Langohr
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Mohammad Faisal
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Margaret McNulty
- School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Caitlin Thorn
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
- * E-mail:
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30
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Dardalhon-Cuménal D, Deraze J, Dupont CA, Ribeiro V, Coléno-Costes A, Pouch J, Le Crom S, Thomassin H, Debat V, Randsholt NB, Peronnet F. Cyclin G and the Polycomb Repressive complexes PRC1 and PR-DUB cooperate for developmental stability. PLoS Genet 2018; 14:e1007498. [PMID: 29995890 PMCID: PMC6065198 DOI: 10.1371/journal.pgen.1007498] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 07/27/2018] [Accepted: 06/19/2018] [Indexed: 12/16/2022] Open
Abstract
In Drosophila, ubiquitous expression of a short Cyclin G isoform generates extreme developmental noise estimated by fluctuating asymmetry (FA), providing a model to tackle developmental stability. This transcriptional cyclin interacts with chromatin regulators of the Enhancer of Trithorax and Polycomb (ETP) and Polycomb families. This led us to investigate the importance of these interactions in developmental stability. Deregulation of Cyclin G highlights an organ intrinsic control of developmental noise, linked to the ETP-interacting domain, and enhanced by mutations in genes encoding members of the Polycomb Repressive complexes PRC1 and PR-DUB. Deep-sequencing of wing imaginal discs deregulating CycG reveals that high developmental noise correlates with up-regulation of genes involved in translation and down-regulation of genes involved in energy production. Most Cyclin G direct transcriptional targets are also direct targets of PRC1 and RNAPolII in the developing wing. Altogether, our results suggest that Cyclin G, PRC1 and PR-DUB cooperate for developmental stability.
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Affiliation(s)
- Delphine Dardalhon-Cuménal
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Jérôme Deraze
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Camille A. Dupont
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Valérie Ribeiro
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Anne Coléno-Costes
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Juliette Pouch
- Institut de biologie de l’Ecole normale supérieure (IBENS), Ecole normale
supérieure, CNRS, INSERM, PSL Université Paris Paris, France
| | - Stéphane Le Crom
- Institut de biologie de l’Ecole normale supérieure (IBENS), Ecole normale
supérieure, CNRS, INSERM, PSL Université Paris Paris, France
- Sorbonne Université, Univ Antilles, Univ Nice Sophia Antipolis, CNRS,
Evolution Paris Seine—Institut de Biologie Paris Seine (EPS - IBPS), Paris,
France
| | - Hélène Thomassin
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Vincent Debat
- Institut de Systematique, Evolution, Biodiversité ISYEB UMR 7205, MNHN,
CNRS, Sorbonne Université, EPHE, Muséum national d'Histoire naturelle, Sorbonne
Universités, Paris, France
| | - Neel B. Randsholt
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
| | - Frédérique Peronnet
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS),
Institut de Biologie Paris-Seine (IBPS), Laboratory of Developmental Biology
(LBD), Paris, France
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31
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Schmähling S, Meiler A, Lee Y, Mohammed A, Finkl K, Tauscher K, Israel L, Wirth M, Philippou-Massier J, Blum H, Habermann B, Imhof A, Song JJ, Müller J. Regulation and function of H3K36 di-methylation by the trithorax-group protein complex AMC. Development 2018. [PMID: 29540501 PMCID: PMC5963871 DOI: 10.1242/dev.163808] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Drosophila Ash1 protein is a trithorax-group (trxG) regulator that antagonizes Polycomb repression at HOX genes. Ash1 di-methylates lysine 36 in histone H3 (H3K36me2) but how this activity is controlled and at which genes it functions is not well understood. We show that Ash1 protein purified from Drosophila exists in a complex with MRG15 and Caf1 that we named AMC. In Drosophila and human AMC, MRG15 binds a conserved FxLP motif near the Ash1 SET domain and stimulates H3K36 di-methylation on nucleosomes. Drosophila MRG15-null and ash1 catalytic mutants show remarkably specific trxG phenotypes: stochastic loss of HOX gene expression and homeotic transformations in adults. In mutants lacking AMC, H3K36me2 bulk levels appear undiminished but H3K36me2 is reduced in the chromatin of HOX and other AMC-regulated genes. AMC therefore appears to act on top of the H3K36me2/me3 landscape generated by the major H3K36 methyltransferases NSD and Set2. Our analyses suggest that H3K36 di-methylation at HOX genes is the crucial physiological function of AMC and the mechanism by which the complex antagonizes Polycomb repression at these genes. Highlighted Article: The trithorax group protein Ash1 and its regulator MRG15 form a multiprotein complex that maintains expression of HOX and other target genes by methylating histone H3 in their chromatin.
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Affiliation(s)
- Sigrun Schmähling
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Arno Meiler
- Max-Planck Institute of Biochemistry, Computational Biology, Am Klopferspitz 18 82152 Martinsried, Germany
| | - Yoonjung Lee
- Korea Advanced Institute of Science and Technology (KAIST), Department of Biological Sciences, Daejeon 34141, Korea
| | - Arif Mohammed
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Katja Finkl
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Katharina Tauscher
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lars Israel
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Marc Wirth
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Julia Philippou-Massier
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Bianca Habermann
- Max-Planck Institute of Biochemistry, Computational Biology, Am Klopferspitz 18 82152 Martinsried, Germany
| | - Axel Imhof
- Zentrallabor für Proteinanalytik, BioMedical Center, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Ji-Joon Song
- Korea Advanced Institute of Science and Technology (KAIST), Department of Biological Sciences, Daejeon 34141, Korea
| | - Jürg Müller
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
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32
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Zhu J, Ordway AJ, Weber L, Buddika K, Kumar JP. Polycomb group (PcG) proteins and Pax6 cooperate to inhibit in vivo reprogramming of the developing Drosophila eye. Development 2018; 145:dev160754. [PMID: 29530880 PMCID: PMC5963869 DOI: 10.1242/dev.160754] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/01/2018] [Indexed: 01/01/2023]
Abstract
How different cells and tissues commit to and determine their fates has been a central question in developmental biology since the seminal embryological experiments conducted by Wilhelm Roux and Hans Driesch in sea urchins and frogs. Here, we demonstrate that Polycomb group (PcG) proteins maintain Drosophila eye specification by suppressing the activation of alternative fate choices. The loss of PcG in the developing eye results in a cellular reprogramming event in which the eye is redirected to a wing fate. This fate transformation occurs with either the individual loss of Polycomb proteins or the simultaneous reduction of the Pleiohomeotic repressive complex and Pax6. Interestingly, the requirement for retinal selector genes is limited to Pax6, as the removal of more downstream members does not lead to the eye-wing transformation. We also show that distinct PcG complexes are required during different developmental windows throughout eye formation. These findings build on earlier observations that the eye can be reprogrammed to initiate head epidermis, antennal and leg development.
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Affiliation(s)
- Jinjin Zhu
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Alison J Ordway
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Lena Weber
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Kasun Buddika
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Justin P Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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33
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Rejlova K, Musilova A, Kramarzova KS, Zaliova M, Fiser K, Alberich-Jorda M, Trka J, Starkova J. Low HOX gene expression in PML-RARα-positive leukemia results from suppressed histone demethylation. Epigenetics 2018; 13:73-84. [PMID: 29224413 DOI: 10.1080/15592294.2017.1413517] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Homeobox (HOX) genes are frequently dysregulated in leukemia. Previous studies have shown that aberrant HOX gene expression accompanies leukemogenesis and affects disease progression and leukemia patient survival. Patients with acute myeloid leukemia (AML) bearing PML-RARα fusion gene have distinct HOX gene signature in comparison to other subtypes of AML patients, although the mechanism of transcription regulation is not completely understood. We previously found an association between the mRNA levels of HOX genes and those of the histone demethylases JMJD3 and UTX in PML-RARα- positive leukemia patients. Here, we demonstrate that the release of the PML-RARα-mediated block in PML-RARα-positive myeloid leukemia cells increased both JMJD3 and HOX gene expression, while inhibition of JMJD3 using the specific inhibitor GSK-J4 reversed the effect. This effect was driven specifically through PML-RARα fusion protein since expression changes did not occur in cells with mutated RARα and was independent of differentiation. We confirmed that gene expression levels were inversely correlated with alterations in H3K27me3 histone marks localized at HOX gene promoters. Furthermore, data from chromatin immunoprecipitation followed by sequencing broaden a list of clustered HOX genes regulated by JMJD3 in PML-RARα-positive leukemic cells. Interestingly, the combination of GSK-J4 and all-trans retinoic acid (ATRA) significantly increased PML-RARα-positive cell apoptosis compared with ATRA treatment alone. This effect was also observed in ATRA-resistant NB4 clones, which may provide a new therapeutic opportunity for patients with acute promyelocytic leukemia (APL) resistant to current treatment. The results of our study reveal the mechanism of HOX gene expression regulation and contribute to our understanding of APL pathogenesis.
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Affiliation(s)
- Katerina Rejlova
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
| | - Alena Musilova
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
| | - Karolina Skvarova Kramarzova
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
| | - Marketa Zaliova
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
| | - Karel Fiser
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
| | | | - Jan Trka
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic.,c University Hospital Motol , Prague , Czech Republic
| | - Julia Starkova
- a CLIP - Childhood Leukaemia Investigation Prague.,b Department of Pediatric Hematology and Oncology , Second Faculty of Medicine, Charles University , Prague , Czech Republic
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34
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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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35
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Khan S, Iqbal M, Tariq M, Baig SM, Abbas W. Epigenetic regulation of HIV-1 latency: focus on polycomb group (PcG) proteins. Clin Epigenetics 2018; 10:14. [PMID: 29441145 PMCID: PMC5800276 DOI: 10.1186/s13148-018-0441-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/05/2018] [Indexed: 01/10/2023] Open
Abstract
HIV-1 latency allows the virus to persist until reactivation, in a transcriptionally silent form in its cellular reservoirs despite the presence of effective cART. Such viral persistence represents a major barrier to HIV eradication since treatment interruption leads to rebound plasma viremia. Polycomb group (PcG) proteins have recently got a considerable attention in regulating HIV-1 post-integration latency as they are involved in the repression of proviral gene expression through the methylation of histones. This epigenetic regulation plays an important role in the establishment and maintenance of HIV-1 latency. In fact, PcG proteins act in complexes and modulate the epigenetic signatures of integrated HIV-1 promoter. Key role played by PcG proteins in the molecular control of HIV-1 latency has led to hypothesize that PcG proteins may represent a valuable target for future HIV-1 therapy in purging HIV-1 reservoirs. In this regard, various small molecules have been synthesized or explored to specifically block the epigenetic activity of PcG. In this review, we will highlight the possible therapeutic approaches to achieve either a functional or sterilizing cure of HIV-1 infection with special focus on histone methylation by PcG proteins together with current and novel pharmacological approaches to reactivate HIV-1 from latency that could ultimately lead towards a better clearance of viral latent reservoirs.
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Affiliation(s)
- Sheraz Khan
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Mazhar Iqbal
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Muhammad Tariq
- Department of Biology (Epigenetics group), SBA School of Science and Engineering, LUMS, Lahore, 54792 Pakistan
| | - Shahid M. Baig
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Wasim Abbas
- Health Biotechnology Division (HBD), National Institute for Biotechnology and Genetic Engineering (NIBGE), PO Box 577, Jhang road, Faisalabad, 38000 Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
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36
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Evidence for the implication of the histone code in building the genome structure. Biosystems 2018; 164:49-59. [DOI: 10.1016/j.biosystems.2017.11.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 11/13/2017] [Accepted: 11/15/2017] [Indexed: 12/13/2022]
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Gupta RP, Bajpai A, Sinha P. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner. Biol Open 2017; 6:1581-1591. [PMID: 29141951 PMCID: PMC5703612 DOI: 10.1242/bio.027821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Eyeless (Ey), and the segment selector, Ultrabithorax (Ubx), readily cooperate to bring about neoplastic transformation of cells displaying somatic loss of the tumor suppressor, Lgl, but in only those developmental domains that express the homeo-box protein, Homothorax (Hth), and/or the Zinc-finger protein, Teashirt (Tsh). In non-Hth/Tsh-expressing domains of these imaginal discs, however, gain of Ey in lgl- somatic clones induces neoplastic transformation in the distal wing disc and haltere, but not in the eye imaginal disc. Likewise, gain of Ubx in lgl- somatic clones induces transformation in the eye imaginal disc but not in its endogenous domain, namely, the haltere imaginal disc. Our results reveal that selector genes could behave as tumor drivers or inhibitors depending on the tissue contexts of their gains.
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Affiliation(s)
- Ram Prakash Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Anjali Bajpai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Pradip Sinha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
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Kang H, Jung YL, McElroy KA, Zee BM, Wallace HA, Woolnough JL, Park PJ, Kuroda MI. Bivalent complexes of PRC1 with orthologs of BRD4 and MOZ/MORF target developmental genes in Drosophila. Genes Dev 2017; 31:1988-2002. [PMID: 29070704 PMCID: PMC5710143 DOI: 10.1101/gad.305987.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 09/28/2017] [Indexed: 02/05/2023]
Abstract
Kang et al. confirm PRC1–Br140 and PRC1–Fs(1)h interactions and identify their genomic binding sites. PRC1–Br140 bind developmental genes in fly embryos, with analogous co-occupancy of PRC1 and BRD1 at bivalent loci in human ES cells. Regulatory decisions in Drosophila require Polycomb group (PcG) proteins to maintain the silent state and Trithorax group (TrxG) proteins to oppose silencing. Since PcG and TrxG are ubiquitous and lack apparent sequence specificity, a long-standing model is that targeting occurs via protein interactions; for instance, between repressors and PcG proteins. Instead, we found that Pc-repressive complex 1 (PRC1) purifies with coactivators Fs(1)h [female sterile (1) homeotic] and Enok/Br140 during embryogenesis. Fs(1)h is a TrxG member and the ortholog of BRD4, a bromodomain protein that binds to acetylated histones and is a key transcriptional coactivator in mammals. Enok and Br140, another bromodomain protein, are orthologous to subunits of a mammalian MOZ/MORF acetyltransferase complex. Here we confirm PRC1–Br140 and PRC1–Fs(1)h interactions and identify their genomic binding sites. PRC1–Br140 bind developmental genes in fly embryos, with analogous co-occupancy of PRC1 and a Br140 ortholog, BRD1, at bivalent loci in human embryonic stem (ES) cells. We propose that identification of PRC1–Br140 “bivalent complexes” in fly embryos supports and extends the bivalency model posited in mammalian cells, in which the coexistence of H3K4me3 and H3K27me3 at developmental promoters represents a poised transcriptional state. We further speculate that local competition between acetylation and deacetylation may play a critical role in the resolution of bivalent protein complexes during development.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Youngsook L Jung
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kyle A McElroy
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Barry M Zee
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Heather A Wallace
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jessica L Woolnough
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Kassis JA, Kennison JA, Tamkun JW. Polycomb and Trithorax Group Genes in Drosophila. Genetics 2017; 206:1699-1725. [PMID: 28778878 PMCID: PMC5560782 DOI: 10.1534/genetics.115.185116] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/15/2017] [Indexed: 01/08/2023] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) genes encode important regulators of development and differentiation in metazoans. These two groups of genes were discovered in Drosophila by their opposing effects on homeotic gene (Hox) expression. PcG genes collectively behave as genetic repressors of Hox genes, while the TrxG genes are necessary for HOX gene expression or function. Biochemical studies showed that many PcG proteins are present in two protein complexes, Polycomb repressive complexes 1 and 2, which repress transcription via chromatin modifications. TrxG proteins activate transcription via a variety of mechanisms. Here we summarize the large body of genetic and biochemical experiments in Drosophila on these two important groups of genes.
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Affiliation(s)
- Judith A Kassis
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - James A Kennison
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - John W Tamkun
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064
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Narendra V, Bulajić M, Dekker J, Mazzoni EO, Reinberg D. CTCF-mediated topological boundaries during development foster appropriate gene regulation. Genes Dev 2017; 30:2657-2662. [PMID: 28087711 PMCID: PMC5238725 DOI: 10.1101/gad.288324.116] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 12/12/2016] [Indexed: 12/11/2022]
Abstract
The genome is organized into repeating topologically associated domains (TADs), each of which is spatially isolated from its neighbor by poorly understood boundary elements thought to be conserved across cell types. Here, we show that deletion of CTCF (CCCTC-binding factor)-binding sites at TAD and sub-TAD topological boundaries that form within the HoxA and HoxC clusters during differentiation not only disturbs local chromatin domain organization and regulatory interactions but also results in homeotic transformations typical of Hox gene misregulation. Moreover, our data suggest that CTCF-dependent boundary function can be modulated by competing forces, such as the self-assembly of polycomb domains within the nucleus. Therefore, CTCF boundaries are not merely static structural components of the genome but instead are locally dynamic regulatory structures that control gene expression during development.
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Affiliation(s)
- Varun Narendra
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
| | - Milica Bulajić
- Department of Biology, New York University, New York, New York 10003, USA
| | - Job Dekker
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Esteban O Mazzoni
- Department of Biology, New York University, New York, New York 10003, USA
| | - Danny Reinberg
- Howard Hughes Medical Institute, New York, New York 10016, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016, USA
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41
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Coleman RT, Struhl G. Causal role for inheritance of H3K27me3 in maintaining the OFF state of a Drosophila HOX gene. Science 2017; 356:eaai8236. [PMID: 28302795 PMCID: PMC5595140 DOI: 10.1126/science.aai8236] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 02/03/2017] [Indexed: 12/20/2022]
Abstract
Many eukaryotic cells can respond to transient environmental or developmental stimuli with heritable changes in gene expression that are associated with nucleosome modifications. However, it remains uncertain whether modified nucleosomes play a causal role in transmitting such epigenetic memories, as opposed to controlling or merely reflecting transcriptional states inherited by other means. Here, we provide in vivo evidence that H3K27 trimethylated nucleosomes, once established at a repressed Drosophila HOX gene, remain heritably associated with that gene and can carry the memory of the silenced state through multiple rounds of replication, even when the capacity to copy the H3K27me3 mark to newly incorporated nucleosomes is diminished or abolished. Hence, in this context, the inheritance of H3K27 trimethylation conveys epigenetic memory.
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Affiliation(s)
- Rory T Coleman
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA
| | - Gary Struhl
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA.
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42
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Wanner N, Bechtel-Walz W. Epigenetics of kidney disease. Cell Tissue Res 2017; 369:75-92. [PMID: 28286899 DOI: 10.1007/s00441-017-2588-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 02/15/2017] [Indexed: 02/06/2023]
Abstract
DNA methylation and histone modifications determine renal programming and the development and progression of renal disease. The identification of the way in which the renal cell epigenome is altered by environmental modifiers driving the onset and progression of renal diseases has extended our understanding of the pathophysiology of kidney disease progression. In this review, we focus on current knowledge concerning the implications of epigenetic modifications during renal disease from early development to chronic kidney disease progression including renal fibrosis, diabetic nephropathy and the translational potential of identifying new biomarkers and treatments for the prevention and therapy of chronic kidney disease and end-stage kidney disease.
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Affiliation(s)
- Nicola Wanner
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Center for Systems Biology (ZBSA), Albert-Ludwigs-University, Freiburg, Germany. .,Renal Division, University Hospital Freiburg, Breisacher Strasse 66, 79106, Freiburg, Germany.
| | - Wibke Bechtel-Walz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Renal Division, University Hospital Freiburg, Breisacher Strasse 66, 79106, Freiburg, Germany.
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43
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Molecular basis of PRC1 targeting to Polycomb response elements by PhoRC. Genes Dev 2017; 30:1116-27. [PMID: 27151979 PMCID: PMC4863741 DOI: 10.1101/gad.279141.116] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
Abstract
Here, Frey et al. report the structural basis by which the Drosophila Pho-repressive complex (PhoRC), the only Polycomb group protein complex with sequence-specific DNA-binding activity, binds to Polycomb-repressive complex 1 (PRC1) and thereby recruits it to Polycomb response elements in target genes. Polycomb group (PcG) protein complexes repress transcription by modifying target gene chromatin. In Drosophila, this repression requires association of PcG protein complexes with cis-regulatory Polycomb response elements (PREs), but the interactions permitting formation of these assemblies are poorly understood. We show that the Sfmbt subunit of the DNA-binding Pho-repressive complex (PhoRC) and the Scm subunit of the canonical Polycomb-repressive complex 1 (PRC1) directly bind each other through their SAM domains. The 1.9 Å crystal structure of the Scm-SAM:Sfmbt-SAM complex reveals the recognition mechanism and shows that Sfmbt-SAM lacks the polymerization capacity of the SAM domains of Scm and its PRC1 partner subunit, Ph. Functional analyses in Drosophila demonstrate that Sfmbt-SAM and Scm-SAM are essential for repression and that PhoRC DNA binding is critical to initiate PRC1 association with PREs. Together, this suggests that PRE-tethered Sfmbt-SAM nucleates PRC1 recruitment and that Scm-SAM/Ph-SAM-mediated polymerization then results in the formation of PRC1-compacted chromatin.
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44
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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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45
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Loubière V, Delest A, Thomas A, Bonev B, Schuettengruber B, Sati S, Martinez AM, Cavalli G. Coordinate redeployment of PRC1 proteins suppresses tumor formation during Drosophila development. Nat Genet 2016; 48:1436-1442. [PMID: 27643538 PMCID: PMC5407438 DOI: 10.1038/ng.3671] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/22/2016] [Indexed: 12/14/2022]
Abstract
Polycomb group proteins form two main complexes, PRC2 and PRC1, which generally coregulate their target genes. Here we show that PRC1 components act as neoplastic tumor suppressors independently of PRC2 function. By mapping the distribution of PRC1 components and trimethylation of histone H3 at Lys27 (H3K27me3) across the genome, we identify a large set of genes that acquire PRC1 in the absence of H3K27me3 in Drosophila larval tissues. These genes massively outnumber canonical targets and are mainly involved in the regulation of cell proliferation, signaling and polarity. Alterations in PRC1 components specifically deregulate this set of genes, whereas canonical targets are derepressed in both PRC1 and PRC2 mutants. In human embryonic stem cells, PRC1 components colocalize with H3K27me3 as in Drosophila embryos, whereas in differentiated cell types they are selectively recruited to a large set of proliferation and signaling-associated genes that lack H3K27me3, suggesting that the redeployment of PRC1 components during development is evolutionarily conserved.
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Affiliation(s)
- Vincent Loubière
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Anna Delest
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Aubin Thomas
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Boyan Bonev
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Bernd Schuettengruber
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Satish Sati
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Anne-Marie Martinez
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
| | - Giacomo Cavalli
- Institute of Human Genetics, UPR1142 CNRS, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Universite de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 5, France
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46
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A positive role for polycomb in transcriptional regulation via H4K20me1. Cell Res 2016; 26:529-42. [PMID: 27002220 PMCID: PMC4856762 DOI: 10.1038/cr.2016.33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 12/24/2022] Open
Abstract
The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc+H3K27me3+H4K20me1+ genes, but not in Pc+H3K27me3+H4K20me1− genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc+H3K27me3+H4K20me1+ genes in developing Drosophila wing disc.
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47
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Bielmeier C, Alt S, Weichselberger V, La Fortezza M, Harz H, Jülicher F, Salbreux G, Classen AK. Interface Contractility between Differently Fated Cells Drives Cell Elimination and Cyst Formation. Curr Biol 2016; 26:563-74. [PMID: 26853359 PMCID: PMC5282066 DOI: 10.1016/j.cub.2015.12.063] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 11/20/2015] [Accepted: 12/16/2015] [Indexed: 01/22/2023]
Abstract
Although cellular tumor-suppression mechanisms are widely studied, little is known about mechanisms that act at the level of tissues to suppress the occurrence of aberrant cells in epithelia. We find that ectopic expression of transcription factors that specify cell fates causes abnormal epithelial cysts in Drosophila imaginal discs. Cysts do not form cell autonomously but result from the juxtaposition of two cell populations with divergent fates. Juxtaposition of wild-type and aberrantly specified cells induces enrichment of actomyosin at their entire shared interface, both at adherens junctions as well as along basolateral interfaces. Experimental validation of 3D vertex model simulations demonstrates that enhanced interface contractility is sufficient to explain many morphogenetic behaviors, which depend on cell cluster size. These range from cyst formation by intermediate-sized clusters to segregation of large cell populations by formation of smooth boundaries or apical constriction in small groups of cells. In addition, we find that single cells experiencing lateral interface contractility are eliminated from tissues by apoptosis. Cysts, which disrupt epithelial continuity, form when elimination of single, aberrantly specified cells fails and cells proliferate to intermediate cell cluster sizes. Thus, increased interface contractility functions as error correction mechanism eliminating single aberrant cells from tissues, but failure leads to the formation of large, potentially disease-promoting cysts. Our results provide a novel perspective on morphogenetic mechanisms, which arise from cell-fate heterogeneities within tissues and maintain or disrupt epithelial homeostasis.
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Affiliation(s)
- Christina Bielmeier
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Silvanus Alt
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany; The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Vanessa Weichselberger
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Marco La Fortezza
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Hartmann Harz
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany
| | - Guillaume Salbreux
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany; The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
| | - Anne-Kathrin Classen
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany.
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48
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Harris RE, Setiawan L, Saul J, Hariharan IK. Localized epigenetic silencing of a damage-activated WNT enhancer limits regeneration in mature Drosophila imaginal discs. eLife 2016; 5. [PMID: 26840050 PMCID: PMC4786413 DOI: 10.7554/elife.11588] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/02/2016] [Indexed: 12/16/2022] Open
Abstract
Many organisms lose the capacity to regenerate damaged tissues as they mature. Damaged Drosophila imaginal discs regenerate efficiently early in the third larval instar (L3) but progressively lose this ability. This correlates with reduced damage-responsive expression of multiple genes, including the WNT genes wingless (wg) and Wnt6. We demonstrate that damage-responsive expression of both genes requires a bipartite enhancer whose activity declines during L3. Within this enhancer, a damage-responsive module stays active throughout L3, while an adjacent silencing element nucleates increasing levels of epigenetic silencing restricted to this enhancer. Cas9-mediated deletion of the silencing element alleviates WNT repression, but is, in itself, insufficient to promote regeneration. However, directing Myc expression to the blastema overcomes repression of multiple genes, including wg, and restores cellular responses necessary for regeneration. Localized epigenetic silencing of damage-responsive enhancers can therefore restrict regenerative capacity in maturing organisms without compromising gene functions regulated by developmental signals.
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Affiliation(s)
- Robin E Harris
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Linda Setiawan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Josh Saul
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Iswar K Hariharan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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The quest for mammalian Polycomb response elements: are we there yet? Chromosoma 2015; 125:471-96. [PMID: 26453572 PMCID: PMC4901126 DOI: 10.1007/s00412-015-0539-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 12/12/2022]
Abstract
A long-standing mystery in the field of Polycomb and Trithorax regulation is how these proteins, which are highly conserved between flies and mammals, can regulate several hundred equally highly conserved target genes, but recognise these targets via cis-regulatory elements that appear to show no conservation in their DNA sequence. These elements, termed Polycomb/Trithorax response elements (PRE/TREs or PREs), are relatively well characterised in flies, but their mammalian counterparts have proved to be extremely difficult to identify. Recent progress in this endeavour has generated a wealth of data and raised several intriguing questions. Here, we ask why and to what extent mammalian PREs are so different to those of the fly. We review recent advances, evaluate current models and identify open questions in the quest for mammalian PREs.
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Kang H, McElroy KA, Jung YL, Alekseyenko AA, Zee BM, Park PJ, Kuroda MI. Sex comb on midleg (Scm) is a functional link between PcG-repressive complexes in Drosophila. Genes Dev 2015; 29:1136-50. [PMID: 26063573 PMCID: PMC4470282 DOI: 10.1101/gad.260562.115] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this study, Kang et al. investigate how PcG complexes form repressive chromatin domains. The findings show that Scm, a transcriptional repressor, is an important regulator of PRC1, PRC2, and transcriptional silencing and suggest that Scm coordinates PcG complexes and polymerizes, resulting in PcG silencing. The Polycomb group (PcG) proteins are key regulators of development in Drosophila and are strongly implicated in human health and disease. How PcG complexes form repressive chromatin domains remains unclear. Using cross-linked affinity purifications of BioTAP-Polycomb (Pc) or BioTAP-Enhancer of zeste [E(z)], we captured all PcG-repressive complex 1 (PRC1) or PRC2 core components and Sex comb on midleg (Scm) as the only protein strongly enriched with both complexes. Although previously not linked to PRC2, we confirmed direct binding of Scm and PRC2 using recombinant protein expression and colocalization of Scm with PRC1, PRC2, and H3K27me3 in embryos and cultured cells using ChIP-seq (chromatin immunoprecipitation [ChIP] combined with deep sequencing). Furthermore, we found that RNAi knockdown of Scm and overexpression of the dominant-negative Scm-SAM (sterile α motif) domain both affected the binding pattern of E(z) on polytene chromosomes. Aberrant localization of the Scm-SAM domain in long contiguous regions on polytene chromosomes revealed its independent ability to spread on chromatin, consistent with its previously described ability to oligomerize in vitro. Pull-downs of BioTAP-Scm captured PRC1 and PRC2 and additional repressive complexes, including PhoRC, LINT, and CtBP. We propose that Scm is a key mediator connecting PRC1, PRC2, and transcriptional silencing. Combined with previous structural and genetic analyses, our results strongly suggest that Scm coordinates PcG complexes and polymerizes to produce broad domains of PcG silencing.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kyle A McElroy
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Youngsook Lucy Jung
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Artyom A Alekseyenko
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Barry M Zee
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA;
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