51
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Buzas DM. Capturing Environmental Plant Memories in DNA, with a Little Help from Chromatin. PLANT & CELL PHYSIOLOGY 2017; 58:1302-1312. [PMID: 28961992 DOI: 10.1093/pcp/pcx092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/28/2017] [Indexed: 05/11/2023]
Abstract
Plants are eukaryotes living mostly immotile in harsh environments. On occasion, it is beneficial for their survival to maintain a transcriptional response to an environmental stress longer than the stress lasts (transcriptional memory) and even to reiterate such a response more quickly or more strongly when the same stress is re-encountered (priming memory). In eukaryotes, transcription takes place in the context of chromatin, the packaging material of DNA. Chromatin regulation is often invoked when it comes to environmental transcriptional and priming memory in plants, but rarely chromatin-based regulation can be accurately assigned to a given aspect of transcription in vivo. The conserved eukaryotic chromatin-modifying system Polycomb/Trithorax can support both long-term stability and flexibility of gene expression in Drosophila. The main principles of Polycomb/Trithorax regulation will be outlined and illustrated with the best-studied case of environmental memory from Arabidopsis. Despite being complex, the Polycomb/Trithorax system relies on experimentally tractable elements in the form of DNA, termed Polycomb/Trithorax Responsive Elements. PREs/TREs are essentially memory DNA elements. Here, relevant information to identify PRE/TRE-like elements in plants is highlighted. Examples of priming memory in plants are discussed in relation to the first two reported putative memory DNA elements. Arguably, similar cases from plants can be conducive in dissecting the contribution of DNA-based from chromatin-based regulation of transcription, when two types of DNA elements are defined: those representing binding sites for the transcription factors determining the environmental response and those controlling memory by regulating chromatin modification dynamics, ultimately maintaining the corresponding transcriptional state.
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Affiliation(s)
- Diana Mihaela Buzas
- Life and Environmental Sciences and Gene Research Centre, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan
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52
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Holoch D, Margueron R. Mechanisms Regulating PRC2 Recruitment and Enzymatic Activity. Trends Biochem Sci 2017; 42:531-542. [DOI: 10.1016/j.tibs.2017.04.003] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 11/29/2022]
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53
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Erceg J, Pakozdi T, Marco-Ferreres R, Ghavi-Helm Y, Girardot C, Bracken AP, Furlong EEM. Dual functionality of cis-regulatory elements as developmental enhancers and Polycomb response elements. Genes Dev 2017; 31:590-602. [PMID: 28381411 PMCID: PMC5393054 DOI: 10.1101/gad.292870.116] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/03/2017] [Indexed: 11/24/2022]
Abstract
Here, Erceg et al. studied the occupancy of the Drosophila PhoRC during embryogenesis and revealed extensive co-occupancy at developmental enhancers. By using an established in vivo assay for Polycomb response element (PRE) activity, they show that a subset of characterized developmental enhancers can function as PREs and silence transcription in a Polycomb-dependent manner, thereby suggesting that reuse of the same elements by the PcG system may help fine-tune gene expression and ensure the timely maintenance of cell identities. Developmental gene expression is tightly regulated through enhancer elements, which initiate dynamic spatio–temporal expression, and Polycomb response elements (PREs), which maintain stable gene silencing. These two cis-regulatory functions are thought to operate through distinct dedicated elements. By examining the occupancy of the Drosophila pleiohomeotic repressive complex (PhoRC) during embryogenesis, we revealed extensive co-occupancy at developmental enhancers. Using an established in vivo assay for PRE activity, we demonstrated that a subset of characterized developmental enhancers can function as PREs, silencing transcription in a Polycomb-dependent manner. Conversely, some classic Drosophila PREs can function as developmental enhancers in vivo, activating spatio–temporal expression. This study therefore uncovers elements with dual function: activating transcription in some cells (enhancers) while stably maintaining transcriptional silencing in others (PREs). Given that enhancers initiate spatio–temporal gene expression, reuse of the same elements by the Polycomb group (PcG) system may help fine-tune gene expression and ensure the timely maintenance of cell identities.
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Affiliation(s)
- Jelena Erceg
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Tibor Pakozdi
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Raquel Marco-Ferreres
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Yad Ghavi-Helm
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Charles Girardot
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
| | - Adrian P Bracken
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Eileen E M Furlong
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany
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54
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Lewis ZA. Polycomb Group Systems in Fungi: New Models for Understanding Polycomb Repressive Complex 2. Trends Genet 2017; 33:220-231. [DOI: 10.1016/j.tig.2017.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/16/2017] [Accepted: 01/17/2017] [Indexed: 02/03/2023]
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55
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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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56
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van Arensbergen J, Dussaud S, Pardanaud-Glavieux C, García-Hurtado J, Sauty C, Guerci A, Ferrer J, Ravassard P. A distal intergenic region controls pancreatic endocrine differentiation by acting as a transcriptional enhancer and as a polycomb response element. PLoS One 2017; 12:e0171508. [PMID: 28225770 PMCID: PMC5321433 DOI: 10.1371/journal.pone.0171508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/02/2017] [Indexed: 12/11/2022] Open
Abstract
Lineage-selective expression of developmental genes is dependent on the interplay between activating and repressive mechanisms. Gene activation is dependent on cell-specific transcription factors that recognize transcriptional enhancer sequences. Gene repression often depends on the recruitment of Polycomb group (PcG) proteins, although the sequences that underlie the recruitment of PcG proteins, also known as Polycomb response elements (PREs), remain poorly understood in vertebrates. While distal PREs have been identified in mammals, a role for positive-acting enhancers in PcG-mediated repression has not been described. Here we have used a highly efficient procedure based on lentiviral-mediated transgenesis to carry out in vivo fine-mapping of, cis-regulatory sequences that control lineage-specific activation of Neurog3, a master regulator of pancreatic endocrine differentiation. Our findings reveal an enhancer region that is sufficient to drive correct spacio-temporal expression of Neurog3 and demonstrate that this same region serves as a PRE in alternative lineages where Neurog3 is inactive.
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Affiliation(s)
- Joris van Arensbergen
- Genomic Programming of Beta-Cells Laboratory, IDIBAPS, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas, Barcelona, Spain
| | - Sebastien Dussaud
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et de la moelle (ICM)–Hôpital Pitié-Salpêtrière, Boulevard de l’Hôpital, Paris, France
| | - Corinne Pardanaud-Glavieux
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et de la moelle (ICM)–Hôpital Pitié-Salpêtrière, Boulevard de l’Hôpital, Paris, France
| | - Javier García-Hurtado
- Genomic Programming of Beta-Cells Laboratory, IDIBAPS, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas, Barcelona, Spain
| | - Claire Sauty
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et de la moelle (ICM)–Hôpital Pitié-Salpêtrière, Boulevard de l’Hôpital, Paris, France
| | - Aline Guerci
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et de la moelle (ICM)–Hôpital Pitié-Salpêtrière, Boulevard de l’Hôpital, Paris, France
| | - Jorge Ferrer
- Genomic Programming of Beta-Cells Laboratory, IDIBAPS, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas, Barcelona, Spain
- Department of Medicine, Imperial Centre for Translational and Experimental Medicine, Imperial College, London, United Kingdom
- * E-mail: (PR); (JF)
| | - Philippe Ravassard
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et de la moelle (ICM)–Hôpital Pitié-Salpêtrière, Boulevard de l’Hôpital, Paris, France
- * E-mail: (PR); (JF)
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57
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Polycomb complexes PRC1 and their function in hematopoiesis. Exp Hematol 2017; 48:12-31. [PMID: 28087428 DOI: 10.1016/j.exphem.2016.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 12/31/2022]
Abstract
Hematopoiesis, the process by which blood cells are continuously produced, is one of the best studied differentiation pathways. Hematological diseases are associated with reiterated mutations in genes encoding important gene expression regulators, including chromatin regulators. Among them, the Polycomb group (PcG) of proteins is an essential system of gene silencing involved in the maintenance of cell identities during differentiation. PcG proteins assemble into two major types of Polycomb repressive complexes (PRCs) endowed with distinct histone-tail-modifying activities. PRC1 complexes are histone H2A E3 ubiquitin ligases and PRC2 trimethylates histone H3. Established conceptions about their activities, mostly derived from work in embryonic stem cells, are being modified by new findings in differentiated cells. Here, we focus on PRC1 complexes, reviewing recent evidence on their intricate architecture, the diverse mechanisms of their recruitment to targets, and the different ways in which they engage in transcriptional control. We also discuss hematopoietic PRC1 gain- and loss-of-function mouse strains, including those that model leukemic and lymphoma diseases, in the belief that these genetic analyses provide the ultimate test for molecular mechanisms driving normal hematopoiesis and hematological malignancies.
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58
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H3K27 methylation: a promiscuous repressive chromatin mark. Curr Opin Genet Dev 2016; 43:31-37. [PMID: 27940208 DOI: 10.1016/j.gde.2016.11.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022]
Abstract
Polycomb Repressive Complex 2 (PRC2) is a multiprotein complex that catalyzes the methylation of lysine 27 on histone H3 (H3K27me). This histone modification is a feature of facultative heterochromatin in many eukaryotes and maintains transcriptional repression established during early development. Understanding how PRC2 targets regions of the genome to be methylated remains poorly understood. Different cell types can show disparate patterns of H3K27me, and chromatin perturbations, such as loss of marks of constitutive heterochromatin, can cause redistribution of H3K27me, implying that DNA sequence, per se, is not sufficient to define the distribution of this mark. Emerging information supports the idea that the chromatin context-including histone modifications, DNA methylation, transcription, chromatin structure and organization within the nucleus-informs PRC2 target selection.
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59
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Comet I, Riising EM, Leblanc B, Helin K. Maintaining cell identity: PRC2-mediated regulation of transcription and cancer. Nat Rev Cancer 2016; 16:803-810. [PMID: 27658528 DOI: 10.1038/nrc.2016.83] [Citation(s) in RCA: 316] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Enhancer of zeste homologue 2 (EZH2), the catalytic subunit of Polycomb repressive complex 2 (PRC2), has attracted broad research attention in the past few years because of its involvement in the development and maintenance of many types of cancer and the use of specific EZH2 inhibitors in clinical trials. Several observations show that PRC2 can have both oncogenic and tumour-suppressive functions. We propose that these apparently opposing roles of PRC2 in cancer are a consequence of the molecular function of the complex in maintaining, rather than specifying, the transcriptional repression state of its several thousand target genes.
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Affiliation(s)
- Itys Comet
- Biotech Research and Innovation Centre (BRIC) and the Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Eva M Riising
- Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Benjamin Leblanc
- Biotech Research and Innovation Centre (BRIC) and the Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Centre (BRIC) and the Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
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60
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Wassef M, Margueron R. The Multiple Facets of PRC2 Alterations in Cancers. J Mol Biol 2016; 429:1978-1993. [PMID: 27742591 DOI: 10.1016/j.jmb.2016.10.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/04/2016] [Accepted: 10/05/2016] [Indexed: 12/12/2022]
Abstract
Genome sequencing of large cohorts of tumors has revealed that mutations in genes encoding chromatin regulators are frequent in cancer. However, the precise contribution of these mutations to tumor development often remains elusive. Here, we review the current knowledge concerning the alterations of the Polycomb machinery in cancer, with a particular focus on the Polycomb repressive complex 2 (PRC2), a key chromatin modifier involved in the maintenance of transcriptional silencing. A broad variety of alterations can impair PRC2 activity; yet, overall, only one type of alteration is found in a given class of tumor. We discuss the potential impact of the various types of PRC2 alterations on gene expression. We propose that the distinct set of genes regulated by PRC2, depending on tumor etiology, constrain the type of alteration of PRC2 that can fuel tumor development. Beyond this specificity, we propose that PRC2 and, more generally, chromatin regulators act as gatekeepers of transcriptional integrity, a role that often confers a tumor-suppressive function.
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Affiliation(s)
- M Wassef
- Institut Curie, PSL Research University, - 26, rue d'Ulm, 75005 Paris, France; INSERM U934, CNRS UMR3215, Paris, France, 75005
| | - R Margueron
- Institut Curie, PSL Research University, - 26, rue d'Ulm, 75005 Paris, France; INSERM U934, CNRS UMR3215, Paris, France, 75005.
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61
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Illingworth RS, Hölzenspies JJ, Roske FV, Bickmore WA, Brickman JM. Polycomb enables primitive endoderm lineage priming in embryonic stem cells. eLife 2016; 5. [PMID: 27723457 PMCID: PMC5056788 DOI: 10.7554/elife.14926] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 09/23/2016] [Indexed: 12/17/2022] Open
Abstract
Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver of these coordinated changes, known as lineage priming, in a process that exploits novel polycomb activities. We find that intragenic levels of the polycomb mark H3K27me3 anti-correlate with changes in transcription, irrespective of the gene's developmental trajectory or identity as a polycomb target. In contrast, promoter proximal H3K27me3 is markedly higher for PrEn priming genes. Consequently, depletion of this modification stimulates the degree to which ESCs are primed towards PrEn when challenged to differentiate, but has little effect on gene expression in self-renewing ESC culture. These observations link polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision.
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Affiliation(s)
- Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Jurriaan J Hölzenspies
- The Danish Stem Cell Centre - DanStem, University of Copenhagen, Copenhagen, Denmark.,MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, Univeristy of Edinburgh, Edinburgh, United Kingdom
| | - Fabian V Roske
- The Danish Stem Cell Centre - DanStem, University of Copenhagen, Copenhagen, Denmark
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Joshua M Brickman
- The Danish Stem Cell Centre - DanStem, University of Copenhagen, Copenhagen, Denmark.,MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, Univeristy of Edinburgh, Edinburgh, United Kingdom
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62
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Rose NR, King HW, Blackledge NP, Fursova NA, Ember KJ, Fischer R, Kessler BM, Klose RJ. RYBP stimulates PRC1 to shape chromatin-based communication between Polycomb repressive complexes. eLife 2016; 5. [PMID: 27705745 PMCID: PMC5065315 DOI: 10.7554/elife.18591] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/01/2016] [Indexed: 12/29/2022] Open
Abstract
Polycomb group (PcG) proteins function as chromatin-based transcriptional repressors that are essential for normal gene regulation during development. However, how these systems function to achieve transcriptional regulation remains very poorly understood. Here, we discover that the histone H2AK119 E3 ubiquitin ligase activity of Polycomb repressive complex 1 (PRC1) is defined by the composition of its catalytic subunits and is highly regulated by RYBP/YAF2-dependent stimulation. In mouse embryonic stem cells, RYBP plays a central role in shaping H2AK119 mono-ubiquitylation at PcG targets and underpins an activity-based communication between PRC1 and Polycomb repressive complex 2 (PRC2) which is required for normal histone H3 lysine 27 trimethylation (H3K27me3). Without normal histone modification-dependent communication between PRC1 and PRC2, repressive Polycomb chromatin domains can erode, rendering target genes susceptible to inappropriate gene expression signals. This suggests that activity-based communication and histone modification-dependent thresholds create a localized form of epigenetic memory required for normal PcG chromatin domain function in gene regulation. DOI:http://dx.doi.org/10.7554/eLife.18591.001
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Affiliation(s)
- Nathan R Rose
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Hamish W King
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Neil P Blackledge
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Nadezda A Fursova
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Katherine Ji Ember
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Roman Fischer
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, United Kingdom
| | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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63
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Zeisig BB, So CWE. Combinatorial Tethering: A Novel Mode to Recruit Non-canonical PRC1 for Normal and Malignant GC B Cell Development. Cancer Cell 2016; 30:185-187. [PMID: 27505665 DOI: 10.1016/j.ccell.2016.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Polycomb repressive complexes (PRCs) are key to normal development and are frequently deregulated in human cancer. In this issue of Cancer Cell, Béguelin et al. report a mechanism of non-canonical PRC1 recruitment by BCL6 in collaboration with EZH2-mediated H3K27me3 for establishment of stable repressive complexes in germinal center B cells.
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Affiliation(s)
- Bernd B Zeisig
- Division of Cancer Studies, Department of Haematological Medicine, Leukaemia and Stem Cell Biology Group, King's College London, Denmark Hill, SE5 9NU London, UK
| | - Chi Wai Eric So
- Division of Cancer Studies, Department of Haematological Medicine, Leukaemia and Stem Cell Biology Group, King's College London, Denmark Hill, SE5 9NU London, UK.
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64
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Béguelin W, Teater M, Gearhart MD, Calvo Fernández MT, Goldstein RL, Cárdenas MG, Hatzi K, Rosen M, Shen H, Corcoran CM, Hamline MY, Gascoyne RD, Levine RL, Abdel-Wahab O, Licht JD, Shaknovich R, Elemento O, Bardwell VJ, Melnick AM. EZH2 and BCL6 Cooperate to Assemble CBX8-BCOR Complex to Repress Bivalent Promoters, Mediate Germinal Center Formation and Lymphomagenesis. Cancer Cell 2016; 30:197-213. [PMID: 27505670 PMCID: PMC5000552 DOI: 10.1016/j.ccell.2016.07.006] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 03/07/2016] [Accepted: 07/13/2016] [Indexed: 11/17/2022]
Abstract
The EZH2 histone methyltransferase mediates the humoral immune response and drives lymphomagenesis through formation of bivalent chromatin domains at critical germinal center (GC) B cell promoters. Herein we show that the actions of EZH2 in driving GC formation and lymphoma precursor lesions require site-specific binding by the BCL6 transcriptional repressor and the presence of a non-canonical PRC1-BCOR-CBX8 complex. The chromodomain protein CBX8 is induced in GC B cells, binds to H3K27me3 at bivalent promoters, and is required for stable association of the complex and the resulting histone modifications. Moreover, oncogenic BCL6 and EZH2 cooperate to accelerate diffuse large B cell lymphoma (DLBCL) development and combinatorial targeting of these repressors results in enhanced anti-lymphoma activity in DLBCLs.
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MESH Headings
- Animals
- Enhancer of Zeste Homolog 2 Protein/metabolism
- Germinal Center/metabolism
- Germinal Center/pathology
- Humans
- Lymphoma, Large B-Cell, Diffuse/genetics
- Lymphoma, Large B-Cell, Diffuse/metabolism
- Lymphoma, Large B-Cell, Diffuse/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mitochondrial Membrane Transport Proteins
- Polycomb Repressive Complex 1/metabolism
- Polycomb-Group Proteins/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-6/metabolism
- Repressor Proteins/metabolism
- Transcription, Genetic
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Affiliation(s)
- Wendy Béguelin
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Matt Teater
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA; Institute for Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY 10021, USA
| | - Micah D Gearhart
- Department of Genetics, Cell Biology, and Development, Developmental Biology Center, Masonic Cancer Center, University of Minnesota, 6-160 Church Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - María Teresa Calvo Fernández
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Rebecca L Goldstein
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Mariano G Cárdenas
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Katerina Hatzi
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Monica Rosen
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Hao Shen
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Connie M Corcoran
- Department of Genetics, Cell Biology, and Development, Developmental Biology Center, Masonic Cancer Center, University of Minnesota, 6-160 Church Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michelle Y Hamline
- Department of Genetics, Cell Biology, and Development, Developmental Biology Center, Masonic Cancer Center, University of Minnesota, 6-160 Church Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - Randy D Gascoyne
- Departments of Pathology and Lymphoid Cancer Research, Centre for Lymphoid Cancer, British Columbia Cancer Agency, British Columbia Cancer Research Centre, Vancouver, BC, V5Z 1L3, Canada
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Jonathan D Licht
- Division of Hematology/Oncology, Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Rita Shaknovich
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA
| | - Olivier Elemento
- Institute for Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY 10021, USA
| | - Vivian J Bardwell
- Department of Genetics, Cell Biology, and Development, Developmental Biology Center, Masonic Cancer Center, University of Minnesota, 6-160 Church Street SE, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Ari M Melnick
- Division of Hematology/Oncology, Department of Medicine, Weill Cornell Medical College, Cornell University, 413 E 69(th) Street, New York, NY 10021, USA.
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65
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Hosogane M, Funayama R, Shirota M, Nakayama K. Lack of Transcription Triggers H3K27me3 Accumulation in the Gene Body. Cell Rep 2016; 16:696-706. [PMID: 27396330 DOI: 10.1016/j.celrep.2016.06.034] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 05/07/2016] [Accepted: 06/05/2016] [Indexed: 10/21/2022] Open
Abstract
Trimethylated H3K27 (H3K27me3) is associated with transcriptional repression, and its abundance in chromatin is frequently altered in cancer. However, it has remained unclear how genomic regions modified by H3K27me3 are specified and formed. We previously showed that downregulation of transcription by oncogenic Ras signaling precedes upregulation of H3K27me3 level. Here, we show that lack of transcription as a result of deletion of the transcription start site of a gene is sufficient to increase H3K27me3 content in the gene body. We further found that histone deacetylation mediates Ras-induced gene silencing and subsequent H3K27me3 accumulation. The H3K27me3 level increased gradually after Ras activation, requiring at least 35 days to achieve saturation. Such maximal accumulation of H3K27me3 was reversed by forced induction of transcription with the dCas9-activator system. Thus, our results indicate that changes in H3K27me3 level, especially in the body of a subset of genes, are triggered by changes in transcriptional activity itself.
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Affiliation(s)
- Masaki Hosogane
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Ryo Funayama
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Matsuyuki Shirota
- Division of Interdisciplinary Medical Sciences, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Keiko Nakayama
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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66
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Kloet SL, Makowski MM, Baymaz HI, van Voorthuijsen L, Karemaker ID, Santanach A, Jansen PWTC, Di Croce L, Vermeulen M. The dynamic interactome and genomic targets of Polycomb complexes during stem-cell differentiation. Nat Struct Mol Biol 2016; 23:682-690. [PMID: 27294783 PMCID: PMC4939079 DOI: 10.1038/nsmb.3248] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 05/17/2016] [Indexed: 12/16/2022]
Abstract
Although the core subunits of Polycomb group (PcG) complexes are well characterized, little is known about the dynamics of these protein complexes during cellular differentiation. We used quantitative interaction proteomics and genome-wide profiling to study PcG proteins in mouse embryonic stem cells (ESCs) and neural progenitor cells (NPCs). We found that the stoichiometry and genome-wide binding of PRC1 and PRC2 were highly dynamic during neural differentiation. Intriguingly, we observed a downregulation and loss of PRC2 from chromatin marked with trimethylated histone H3 K27 (H3K27me3) during differentiation, whereas PRC1 was retained at these sites. Additionally, we found PRC1 at enhancer and promoter regions independently of PRC2 binding and H3K27me3. Finally, overexpression of NPC-specific PRC1 interactors in ESCs led to increased Ring1b binding to, and decreased expression of, NPC-enriched Ring1b-target genes. In summary, our integrative analyses uncovered dynamic PcG subcomplexes and their widespread colocalization with active chromatin marks during differentiation.
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Affiliation(s)
- Susan L Kloet
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - Matthew M Makowski
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - H Irem Baymaz
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - Lisa van Voorthuijsen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - Ino D Karemaker
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - Alexandra Santanach
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Biomedical Genetics, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Pascal W T C Jansen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands
| | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Biomedical Genetics, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands.,Cancer GenomiCs.nl (CGC.nl) Consortium, Center for Molecular Medicine, UMC Utrecht, The Netherlands
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67
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Entrevan M, Schuettengruber B, Cavalli G. Regulation of Genome Architecture and Function by Polycomb Proteins. Trends Cell Biol 2016; 26:511-525. [PMID: 27198635 DOI: 10.1016/j.tcb.2016.04.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 12/13/2022]
Abstract
Polycomb group (PcG) proteins dynamically define cellular identities through the epigenetic repression of key developmental regulatory genes. PcG proteins are recruited to specific regulatory elements to modify the chromatin surrounding them. In addition, they regulate the organization of their target genes in the 3D space of the nucleus, and this regulatory function of the 3D genome architecture is involved in cell differentiation and the maintenance of cellular memory. In this review we discuss recent advances in our understanding of how PcG proteins are recruited to chromatin to induce local and global changes in chromosome conformation and regulate their target genes.
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Affiliation(s)
- Marianne Entrevan
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Bernd Schuettengruber
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France.
| | - Giacomo Cavalli
- Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France.
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68
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Beltran M, Yates CM, Skalska L, Dawson M, Reis FP, Viiri K, Fisher CL, Sibley CR, Foster BM, Bartke T, Ule J, Jenner RG. The interaction of PRC2 with RNA or chromatin is mutually antagonistic. Genome Res 2016; 26:896-907. [PMID: 27197219 PMCID: PMC4937559 DOI: 10.1101/gr.197632.115] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 05/05/2016] [Indexed: 12/17/2022]
Abstract
Polycomb repressive complex 2 (PRC2) modifies chromatin to maintain genes in a repressed state during development. PRC2 is primarily associated with CpG islands at repressed genes and also possesses RNA binding activity. However, the RNAs that bind PRC2 in cells, the subunits that mediate these interactions, and the role of RNA in PRC2 recruitment to chromatin all remain unclear. By performing iCLIP for PRC2 in comparison with other RNA binding proteins, we show here that PRC2 binds nascent RNA at essentially all active genes. Although interacting with RNA promiscuously, PRC2 binding is enriched at specific locations within RNAs, primarily exon–intron boundaries and the 3′ UTR. Deletion of other PRC2 subunits reveals that SUZ12 is sufficient to establish this RNA binding profile. Contrary to prevailing models, we also demonstrate that the interaction of PRC2 with RNA or chromatin is mutually antagonistic in cells and in vitro. RNA degradation in cells triggers PRC2 recruitment to CpG islands at active genes. Correspondingly, the release of PRC2 from chromatin in cells increases RNA binding. Consistent with this, RNA and nucleosomes compete for PRC2 binding in vitro. We propose that RNA prevents PRC2 recruitment to chromatin at active genes and that mutual antagonism between RNA and chromatin underlies the pattern of PRC2 chromatin association across the genome.
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Affiliation(s)
- Manuel Beltran
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Christopher M Yates
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Lenka Skalska
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Marcus Dawson
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Filipa P Reis
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Keijo Viiri
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Cynthia L Fisher
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Christopher R Sibley
- Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
| | - Benjamin M Foster
- MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Till Bartke
- MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
| | - Richard G Jenner
- UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
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69
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Minnich M, Tagoh H, Bönelt P, Axelsson E, Fischer M, Cebolla B, Tarakhovsky A, Nutt SL, Jaritz M, Busslinger M. Multifunctional role of the transcription factor Blimp-1 in coordinating plasma cell differentiation. Nat Immunol 2016; 17:331-43. [PMID: 26779602 PMCID: PMC5790184 DOI: 10.1038/ni.3349] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 11/05/2015] [Indexed: 12/29/2022]
Abstract
The transcription factor Blimp-1 is necessary for the generation of plasma cells. Here we studied its functions in plasmablast differentiation by identifying regulated Blimp-1 target genes. Blimp-1 promoted the migration and adhesion of plasmablasts. It directly repressed genes encoding several transcription factors and Aicda (which encodes the cytidine deaminase AID) and thus silenced B cell-specific gene expression, antigen presentation and class-switch recombination in plasmablasts. It directly activated genes, which led to increased expression of the plasma cell regulator IRF4 and proteins involved in immunoglobulin secretion. Blimp-1 induced the transcription of immunoglobulin genes by controlling the 3' enhancers of the loci encoding the immunoglobulin heavy chain (Igh) and κ-light chain (Igk) and, furthermore, regulated the post-transcriptional expression switch from the membrane-bound form of the immunoglobulin heavy chain to its secreted form by activating Ell2 (which encodes the transcription-elongation factor ELL2). Notably, Blimp-1 recruited chromatin-remodeling and histone-modifying complexes to regulate its target genes. Hence, many essential functions of plasma cells are under the control of Blimp-1.
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Affiliation(s)
- Martina Minnich
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Hiromi Tagoh
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Peter Bönelt
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Elin Axelsson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Maria Fischer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Beatriz Cebolla
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | | | - Stephen L. Nutt
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Markus Jaritz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Meinrad Busslinger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
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70
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An interactive environment for agile analysis and visualization of ChIP-sequencing data. Nat Struct Mol Biol 2016; 23:349-57. [PMID: 26926434 DOI: 10.1038/nsmb.3180] [Citation(s) in RCA: 176] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/29/2016] [Indexed: 02/08/2023]
Abstract
To empower experimentalists with a means for fast and comprehensive chromatin immunoprecipitation sequencing (ChIP-seq) data analyses, we introduce an integrated computational environment, EaSeq. The software combines the exploratory power of genome browsers with an extensive set of interactive and user-friendly tools for genome-wide abstraction and visualization. It enables experimentalists to easily extract information and generate hypotheses from their own data and public genome-wide datasets. For demonstration purposes, we performed meta-analyses of public Polycomb ChIP-seq data and established a new screening approach to analyze more than 900 datasets from mouse embryonic stem cells for factors potentially associated with Polycomb recruitment. EaSeq, which is freely available and works on a standard personal computer, can substantially increase the throughput of many analysis workflows, facilitate transparency and reproducibility by automatically documenting and organizing analyses, and enable a broader group of scientists to gain insights from ChIP-seq data.
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71
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Boeva V. Analysis of Genomic Sequence Motifs for Deciphering Transcription Factor Binding and Transcriptional Regulation in Eukaryotic Cells. Front Genet 2016; 7:24. [PMID: 26941778 PMCID: PMC4763482 DOI: 10.3389/fgene.2016.00024] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 02/05/2016] [Indexed: 12/27/2022] Open
Abstract
Eukaryotic genomes contain a variety of structured patterns: repetitive elements, binding sites of DNA and RNA associated proteins, splice sites, and so on. Often, these structured patterns can be formalized as motifs and described using a proper mathematical model such as position weight matrix and IUPAC consensus. Two key tasks are typically carried out for motifs in the context of the analysis of genomic sequences. These are: identification in a set of DNA regions of over-represented motifs from a particular motif database, and de novo discovery of over-represented motifs. Here we describe existing methodology to perform these two tasks for motifs characterizing transcription factor binding. When applied to the output of ChIP-seq and ChIP-exo experiments, or to promoter regions of co-modulated genes, motif analysis techniques allow for the prediction of transcription factor binding events and enable identification of transcriptional regulators and co-regulators. The usefulness of motif analysis is further exemplified in this review by how motif discovery improves peak calling in ChIP-seq and ChIP-exo experiments and, when coupled with information on gene expression, allows insights into physical mechanisms of transcriptional modulation.
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Affiliation(s)
- Valentina Boeva
- Centre de Recherche, Institut CurieParis, France; INSERM, U900Paris, France; Mines ParisTechFontainebleau, France; PSL Research UniversityParis, France; Department of Development, Reproduction and Cancer, Institut CochinParis, France; INSERM, U1016Paris, France; Centre National de la Recherche Scientifique UMR 8104Paris, France; Université Paris Descartes UMR-S1016Paris, France
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72
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Affiliation(s)
- Sanchita Bhatnagar
- a Howard Hughes Medical Institute and Department of Molecular , Cell and Cancer Biology; University of Massachusetts Medical School ; Worcester , MA USA
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73
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RNA binding proteins implicated in Xist-mediated chromosome silencing. Semin Cell Dev Biol 2016; 56:58-70. [PMID: 26816113 DOI: 10.1016/j.semcdb.2016.01.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Chromosome silencing by Xist RNA occurs in two steps; localisation in cis within the nuclear matrix to form a domain that corresponds to the territory of the inactive X chromosome elect, and transduction of silencing signals from Xist RNA to the underlying chromatin. Key factors that mediate these processes have been identified in a series of recent studies that harnessed comprehensive proteomic or genetic screening strategies. In this review we discuss these findings in light of prior knowledge both of Xist-mediated silencing and known functions/properties of the novel factors.
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74
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Abstract
Epigenomics has grown exponentially, providing a better understanding of the mechanistic aspects of new and old phenomena originally described through genetics, as well as providing unexpected insights into the way chromatin modulates the genomic information. In this overview, some of the advances are selected for discussion and comment under six topics: (1) histone modifications, (2) weak interactions, (3) interplay with external inputs, (4) the role of RNA molecules, (5) chromatin folding and architecture, and, finally, (6) a view of the essential role of chromatin transactions in regulating the access to genomic DNA.
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Affiliation(s)
- Vincenzo Pirrotta
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854
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75
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Illingworth RS, Moffat M, Mann AR, Read D, Hunter CJ, Pradeepa MM, Adams IR, Bickmore WA. The E3 ubiquitin ligase activity of RING1B is not essential for early mouse development. Genes Dev 2015; 29:1897-902. [PMID: 26385961 PMCID: PMC4579347 DOI: 10.1101/gad.268151.115] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Polycomb-repressive complex 1 (PRC1) and PRC2 maintain repression at many developmental genes in mouse embryonic stem cells and are required for early development. However, it is still unclear how they are targeted and how they function. We show that the ability of RING1B, a core component of PRC1, to ubiquitinate histone H2A is dispensable for early mouse embryonic development and much of the gene repression activity of PRC1. Our data support a model in which PRC1 and PRC2 reinforce each other's binding but suggest that the key functions of PRC1 lie beyond the enzymatic capabilities of RING1B.
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Affiliation(s)
- Robert S Illingworth
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Michael Moffat
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Abigail R Mann
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - David Read
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Chris J Hunter
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Madapura M Pradeepa
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Ian R Adams
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Wendy A Bickmore
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
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76
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Martins NMC, Bergmann JH, Shono N, Kimura H, Larionov V, Masumoto H, Earnshaw WC. Epigenetic engineering shows that a human centromere resists silencing mediated by H3K27me3/K9me3. Mol Biol Cell 2015; 27:177-96. [PMID: 26564795 PMCID: PMC4694756 DOI: 10.1091/mbc.e15-08-0605] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/03/2015] [Indexed: 12/14/2022] Open
Abstract
Centromeres are embedded within heterochromatin but are transcriptionally active. Centromeric transcription and the centromere function of a human artificial chromosome resist repression mediated by nucleation of repressive marks H3K27me3 or H3K9me3 via tethering of EZH2 or the SET domain of Suv39h1, respectively. Centromeres are characterized by the centromere-specific H3 variant CENP-A, which is embedded in chromatin with a pattern characteristic of active transcription that is required for centromere identity. It is unclear how centromeres remain transcriptionally active despite being flanked by repressive pericentric heterochromatin. To further understand centrochromatin’s response to repressive signals, we nucleated a Polycomb-like chromatin state within the centromere of a human artificial chromosome (HAC) by tethering the methyltransferase EZH2. This led to deposition of the H3K27me3 mark and PRC1 repressor binding. Surprisingly, this state did not abolish HAC centromere function or transcription, and this apparent resistance was not observed on a noncentromeric locus, where transcription was silenced. Directly tethering the reader/repressor PRC1 bypassed this resistance, inactivating the centromere. We observed analogous responses when tethering the heterochromatin Editor Suv39h1-methyltransferase domain (centromere resistance) or reader HP1α (centromere inactivation), respectively. Our results reveal that the HAC centromere can resist repressive pathways driven by H3K9me3/H3K27me3 and may help to explain how centromeres are able to resist inactivation by flanking heterochromatin.
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Affiliation(s)
- Nuno M C Martins
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom
| | - Jan H Bergmann
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom
| | - Nobuaki Shono
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu 292-0818, Japan Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Hiroshi Kimura
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Vladimir Larionov
- Laboratory of Molecular Pharmacology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Hiroshi Masumoto
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu 292-0818, Japan
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom
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77
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Blackledge NP, Rose NR, Klose RJ. Targeting Polycomb systems to regulate gene expression: modifications to a complex story. Nat Rev Mol Cell Biol 2015; 16:643-649. [PMID: 26420232 DOI: 10.1038/nrm4067.targeting] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Polycomb group proteins are transcriptional repressors that are essential for normal gene regulation during development. Recent studies suggest that Polycomb repressive complexes (PRCs) recognize and are recruited to their genomic target sites through a range of different mechanisms, which involve transcription factors, CpG island elements and non-coding RNAs. Together with the realization that the interplay between PRC1 and PRC2 is more intricate than was previously appreciated, this has increased our understanding of the vertebrate Polycomb system at the molecular level.
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Affiliation(s)
- Neil P Blackledge
- Department of Biochemistry, South Parks Road, University of Oxford, OX1 3QU
| | - Nathan R Rose
- Department of Biochemistry, South Parks Road, University of Oxford, OX1 3QU
| | - Robert J Klose
- Department of Biochemistry, South Parks Road, University of Oxford, OX1 3QU
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78
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Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers. Genes (Basel) 2015; 6:1076-112. [PMID: 26506391 PMCID: PMC4690029 DOI: 10.3390/genes6041076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/30/2015] [Accepted: 10/07/2015] [Indexed: 12/21/2022] Open
Abstract
We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation.
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79
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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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Targeting Polycomb systems to regulate gene expression: modifications to a complex story. Nat Rev Mol Cell Biol 2015; 16:643-649. [PMID: 26420232 DOI: 10.1038/nrm4067] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Polycomb group proteins are transcriptional repressors that are essential for normal gene regulation during development. Recent studies suggest that Polycomb repressive complexes (PRCs) recognize and are recruited to their genomic target sites through a range of different mechanisms, which involve transcription factors, CpG island elements and non-coding RNAs. Together with the realization that the interplay between PRC1 and PRC2 is more intricate than was previously appreciated, this has increased our understanding of the vertebrate Polycomb system at the molecular level.
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81
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Maupetit-Méhouas S, Montibus B, Nury D, Tayama C, Wassef M, Kota SK, Fogli A, Cerqueira Campos F, Hata K, Feil R, Margueron R, Nakabayashi K, Court F, Arnaud P. Imprinting control regions (ICRs) are marked by mono-allelic bivalent chromatin when transcriptionally inactive. Nucleic Acids Res 2015; 44:621-35. [PMID: 26400168 PMCID: PMC4737186 DOI: 10.1093/nar/gkv960] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/12/2015] [Indexed: 01/10/2023] Open
Abstract
Parental allele-specific expression of imprinted genes is mediated by imprinting control regions (ICRs) that are constitutively marked by DNA methylation imprints on the maternal or paternal allele. Mono-allelic DNA methylation is strictly required for the process of imprinting and has to be faithfully maintained during the entire life-span. While the regulation of DNA methylation itself is well understood, the mechanisms whereby the opposite allele remains unmethylated are unclear. Here, we show that in the mouse, at maternally methylated ICRs, the paternal allele, which is constitutively associated with H3K4me2/3, is marked by default by H3K27me3 when these ICRs are transcriptionally inactive, leading to the formation of a bivalent chromatin signature. Our data suggest that at ICRs, chromatin bivalency has a protective role by ensuring that DNA on the paternal allele remains unmethylated and protected against spurious and unscheduled gene expression. Moreover, they provide the proof of concept that, beside pluripotent cells, chromatin bivalency is the default state of transcriptionally inactive CpG island promoters, regardless of the developmental stage, thereby contributing to protect cell identity.
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Affiliation(s)
- Stéphanie Maupetit-Méhouas
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - Bertille Montibus
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - David Nury
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - Chiharu Tayama
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan
| | - Michel Wassef
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Satya K Kota
- Institute of Molecular Genetics, CNRS UMR-5535 and University of Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | - Anne Fogli
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - Fabiana Cerqueira Campos
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - Kenichiro Hata
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan
| | - Robert Feil
- Institute of Molecular Genetics, CNRS UMR-5535 and University of Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | - Raphael Margueron
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Kazuhiko Nakabayashi
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan
| | - Franck Court
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
| | - Philippe Arnaud
- CNRS, UMR6293, F-63001 Clermont-Ferrand, France Inserm, U1103, 63001 Clermont-Ferrand, France Université Clermont Auvergne, Laboratoire GReD, BP 10448, 63000 Clermont-Ferrand, France
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82
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Berry S, Dean C. Environmental perception and epigenetic memory: mechanistic insight through FLC. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:133-48. [PMID: 25929799 PMCID: PMC4691321 DOI: 10.1111/tpj.12869] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/13/2015] [Accepted: 04/20/2015] [Indexed: 05/18/2023]
Abstract
Chromatin plays a central role in orchestrating gene regulation at the transcriptional level. However, our understanding of how chromatin states are altered in response to environmental and developmental cues, and then maintained epigenetically over many cell divisions, remains poor. The floral repressor gene FLOWERING LOCUS C (FLC) in Arabidopsis thaliana is a useful system to address these questions. FLC is transcriptionally repressed during exposure to cold temperatures, allowing studies of how environmental conditions alter expression states at the chromatin level. FLC repression is also epigenetically maintained during subsequent development in warm conditions, so that exposure to cold may be remembered. This memory depends on molecular complexes that are highly conserved among eukaryotes, making FLC not only interesting as a paradigm for understanding biological decision-making in plants, but also an important system for elucidating chromatin-based gene regulation more generally. In this review, we summarize our understanding of how cold temperature induces a switch in the FLC chromatin state, and how this state is epigenetically remembered. We also discuss how the epigenetic state of FLC is reprogrammed in the seed to ensure a requirement for cold exposure in the next generation.
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Affiliation(s)
- Scott Berry
- John Innes Centre, Norwich Research ParkNorwich, NR4 7UH, UK
| | - Caroline Dean
- John Innes Centre, Norwich Research ParkNorwich, NR4 7UH, UK
- * For correspondence (e-mail )
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83
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Abou El Hassan M, Huang K, Eswara MBK, Zhao M, Song L, Yu T, Liu Y, Liu JC, McCurdy S, Ma A, Wither J, Jin J, Zacksenhaus E, Wrana JL, Bremner R. Cancer Cells Hijack PRC2 to Modify Multiple Cytokine Pathways. PLoS One 2015; 10:e0126466. [PMID: 26030458 PMCID: PMC4450877 DOI: 10.1371/journal.pone.0126466] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/03/2015] [Indexed: 01/21/2023] Open
Abstract
Polycomb Repressive Complex 2 (PRC2) is an epigenetic regulator induced in many cancers. It is thought to drive tumorigenesis by repressing division, stemness, and/or developmental regulators. Cancers evade immune detection, and diverse immune regulators are perturbed in different tumors. It is unclear how such cell-specific effects are coordinated. Here, we show a profound and cancer-selective role for PRC2 in repressing multiple cytokine pathways. We find that PRC2 represses hundreds of IFNγ stimulated genes (ISGs), cytokines and cytokine receptors. This target repertoire is significantly broadened in cancer vs non-cancer cells, and is distinct in different cancer types. PRC2 is therefore a higher order regulator of the immune program in cancer cells. Inhibiting PRC2 with either RNAi or EZH2 inhibitors activates cytokine/cytokine receptor promoters marked with bivalent H3K27me3/H3K4me3 chromatin, and augments responsiveness to diverse immune signals. PRC2 inhibition rescues immune gene induction even in the absence of SWI/SNF, a tumor suppressor defective in ~20% of human cancers. This novel PRC2 function in tumor cells could profoundly impact the mechanism of action and efficacy of EZH2 inhibitors in cancer treatment.
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Affiliation(s)
| | - Katherine Huang
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Manoja B. K. Eswara
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Michael Zhao
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Lan Song
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Tao Yu
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Yu Liu
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Jeffrey C. Liu
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Sean McCurdy
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Anqi Ma
- Department of Structural and Chemical Biology, Icahn School of Medicine, Mt Sinai Hospital, New York, New York, United States of America
| | - Joan Wither
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jian Jin
- Department of Structural and Chemical Biology, Icahn School of Medicine, Mt Sinai Hospital, New York, New York, United States of America
| | - Eldad Zacksenhaus
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey L. Wrana
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
| | - Rod Bremner
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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84
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Berry S, Hartley M, Olsson TSG, Dean C, Howard M. Local chromatin environment of a Polycomb target gene instructs its own epigenetic inheritance. eLife 2015; 4:e07205. [PMID: 25955967 PMCID: PMC4450441 DOI: 10.7554/elife.07205] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/07/2015] [Indexed: 01/10/2023] Open
Abstract
Inheritance of gene expression states is fundamental for cells to 'remember' past events, such as environmental or developmental cues. The conserved Polycomb Repressive Complex 2 (PRC2) maintains epigenetic repression of many genes in animals and plants and modifies chromatin at its targets. Histones modified by PRC2 can be inherited through cell division. However, it remains unclear whether this inheritance can direct long-term memory of individual gene expression states (cis memory) or instead if local chromatin states are dictated by the concentrations of diffusible factors (trans memory). By monitoring the expression of two copies of the Arabidopsis Polycomb target gene FLOWERING LOCUS C (FLC) in the same plants, we show that one copy can be repressed while the other is active. Furthermore, this 'mixed' expression state is inherited through many cell divisions as plants develop. These data demonstrate that epigenetic memory of FLC expression is stored not in trans but in cis.
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85
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86
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Abstract
Transcriptional regulation of thousands of genes instructs complex morphogenetic and molecular events for heart development. Cardiac transcription factors choreograph gene expression at each stage of differentiation by interacting with cofactors, including chromatin-modifying enzymes, and by binding to a constellation of regulatory DNA elements. Here, we present salient examples relevant to cardiovascular development and heart disease, and review techniques that can sharpen our understanding of cardiovascular biology. We discuss the interplay between cardiac transcription factors, cis-regulatory elements, and chromatin as dynamic regulatory networks, to orchestrate sequential deployment of the cardiac gene expression program.
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Affiliation(s)
- Irfan S Kathiriya
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
| | - Elphège P Nora
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
| | - Benoit G Bruneau
- From the Gladstone Institute of Cardiovascular Disease and the Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA (I.S.K., E.P.N., B.G.B.); and Department of Anesthesia and Perioperative Care (I.S.K.), Department of Pediatrics (B.G.B.), Cardiovascular Research Institute (B.G.B.), and Institute for Regeneration Medicine (B.G.B.), University of California, San Francisco.
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87
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Sanulli S, Justin N, Teissandier A, Ancelin K, Portoso M, Caron M, Michaud A, Lombard B, da Rocha ST, Offer J, Loew D, Servant N, Wassef M, Burlina F, Gamblin SJ, Heard E, Margueron R. Jarid2 Methylation via the PRC2 Complex Regulates H3K27me3 Deposition during Cell Differentiation. Mol Cell 2015; 57:769-783. [PMID: 25620564 PMCID: PMC4352895 DOI: 10.1016/j.molcel.2014.12.020] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 08/01/2014] [Accepted: 12/12/2014] [Indexed: 02/06/2023]
Abstract
Polycomb Group (PcG) proteins maintain transcriptional repression throughout development, mostly by regulating chromatin structure. Polycomb Repressive Complex 2 (PRC2), a component of the Polycomb machinery, is responsible for the methylation of histone H3 lysine 27 (H3K27me2/3). Jarid2 was previously identified as a cofactor of PRC2, regulating PRC2 targeting to chromatin and its enzymatic activity. Deletion of Jarid2 leads to impaired orchestration of gene expression during cell lineage commitment. Here, we reveal an unexpected crosstalk between Jarid2 and PRC2, with Jarid2 being methylated by PRC2. This modification is recognized by the Eed core component of PRC2 and triggers an allosteric activation of PRC2’s enzymatic activity. We show that Jarid2 methylation is important to promote PRC2 activity at a locus devoid of H3K27me3 and for the correct deposition of this mark during cell differentiation. Our results uncover a regulation loop where Jarid2 methylation fine-tunes PRC2 activity depending on the chromatin context. PRC2 methylates Jarid2 on K116 Jarid2 methylation promotes PRC2 activity H3K27me3 and Jarid2-K116me3 bind to the aromatic cage of Eed Jarid2 methylation regulates H3K27me3 deposition during ESC differentiation
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Affiliation(s)
- Serena Sanulli
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Neil Justin
- MRC National Institute for Medical Research, The Ridgeway, London, Mill Hill NW7 1AA, UK
| | - Aurélie Teissandier
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U900, 26 Rue d'Ulm, 75005 Paris, France; Mines ParisTech, 35 Rue Saint Honoré, 77305 Fontainebleau, France
| | - Katia Ancelin
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Manuela Portoso
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Matthieu Caron
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Audrey Michaud
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Berangère Lombard
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; Laboratory of Proteomics and Mass Spectrometry, 26 Rue d'Ulm, 75005 Paris, France
| | - Simao T da Rocha
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - John Offer
- MRC National Institute for Medical Research, The Ridgeway, London, Mill Hill NW7 1AA, UK
| | - Damarys Loew
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; Laboratory of Proteomics and Mass Spectrometry, 26 Rue d'Ulm, 75005 Paris, France
| | - Nicolas Servant
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U900, 26 Rue d'Ulm, 75005 Paris, France; Mines ParisTech, 35 Rue Saint Honoré, 77305 Fontainebleau, France
| | - Michel Wassef
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Fabienne Burlina
- Sorbonnes Universités, UPMC Univ Paris 06, CNRS, ENS, UMR7203 LBM, 4 Place Jussieu, 75005 Paris, France
| | - Steve J Gamblin
- MRC National Institute for Medical Research, The Ridgeway, London, Mill Hill NW7 1AA, UK
| | - Edith Heard
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France
| | - Raphaël Margueron
- Institut Curie, 26 Rue d'Ulm, 75005 Paris, France; INSERM U934, 26 Rue d'Ulm, 75005 Paris, France; CNRS UMR3215, 26 Rue d'Ulm, 75005 Paris, France.
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88
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Bravo M, Nicolini F, Starowicz K, Barroso S, Calés C, Aguilera A, Vidal M. Polycomb RING1A/RING1B-dependent histone H2A monoubiquitylation at pericentromeric regions promotes S phase progression. J Cell Sci 2015; 128:3660-71. [DOI: 10.1242/jcs.173021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/12/2015] [Indexed: 12/22/2022] Open
Abstract
Functions of Polycomb products extend beyond their well known activity as transcriptional regulators to include genome duplication processes. Polycomb activities in DNA replication and DNA damage repair are unclear, particularly without induced replicative stress. We have used a cellular model of conditionally inactive Polycomb E3 ligases (RING1A and RING1B) that monoubiquitylate lysine 119 of histone H2A (H2AK119Ub) to examine DNA replication in unperturbed cells. We identify slow elongation and fork stalling during DNA replication, associated to the accumulation of mid and late S cells. Signs of replicative stress and colocalization of double strand breaks with chromocenters, the sites of coalesced pericentromeric heterocromatic (PCH) domains, were enriched in cells at mid S, the stage at which PCH is replicated. Altered replication was rescued by targeted monoubiquitylation of PCH through methyl-CpG binding domain protein 1. The acute senescence associated to the depletion of RING1 proteins, mediated by CDKN1A/p21 upregulation, could be uncoupled from a response to DNA damage. These findings link cell proliferation and Polycomb RING1A/B to S phase progression through a specific function in PCH replication.
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Affiliation(s)
- Mónica Bravo
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Fabio Nicolini
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Katarzyna Starowicz
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
| | - Sonia Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092 Sevilla, Spain
| | - Carmela Calés
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28029 Madrid, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092 Sevilla, Spain
| | - Miguel Vidal
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain
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89
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Affiliation(s)
- Chris O'Neill
- Kolling Institute for Medical Research, Sydney Medical School, Royal North Shore Hospital, NSW, 2065 Australia
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90
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Product binding enforces the genomic specificity of a yeast polycomb repressive complex. Cell 2014; 160:204-18. [PMID: 25533783 DOI: 10.1016/j.cell.2014.11.039] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/30/2014] [Accepted: 11/12/2014] [Indexed: 11/22/2022]
Abstract
We characterize the Polycomb system that assembles repressive subtelomeric domains of H3K27 methylation (H3K27me) in the yeast Cryptococcus neoformans. Purification of this PRC2-like protein complex reveals orthologs of animal PRC2 components as well as a chromodomain-containing subunit, Ccc1, which recognizes H3K27me. Whereas removal of either the EZH or EED ortholog eliminates H3K27me, disruption of mark recognition by Ccc1 causes H3K27me to redistribute. Strikingly, the resulting pattern of H3K27me coincides with domains of heterochromatin marked by H3K9me. Indeed, additional removal of the C. neoformans H3K9 methyltransferase Clr4 results in loss of both H3K9me and the redistributed H3K27me marks. These findings indicate that the anchoring of a chromatin-modifying complex to its product suppresses its attraction to a different chromatin type, explaining how enzymes that act on histones, which often harbor product recognition modules, may deposit distinct chromatin domains despite sharing a highly abundant and largely identical substrate-the nucleosome.
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91
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Scelfo A, Piunti A, Pasini D. The controversial role of the Polycomb group proteins in transcription and cancer: how much do we not understand Polycomb proteins? FEBS J 2014; 282:1703-22. [PMID: 25315766 DOI: 10.1111/febs.13112] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/03/2014] [Accepted: 10/14/2014] [Indexed: 12/21/2022]
Abstract
Polycomb group proteins (PcGs) are a large protein family that includes diverse biochemical features assembled together in two large multiprotein complexes. These complexes maintain gene transcriptional repression in a cell type specific manner by modifying the surrounding chromatin to control development, differentiation and cell proliferation. PcGs are also involved in several diseases. PcGs are often directly or indirectly implicated in cancer development for which they have been proposed as potential targets for cancer therapeutic strategies. However, in the last few years a series of discoveries about the basic properties of PcGs and the identification of specific genetic alterations affecting specific Polycomb proteins in different tumours have converged to challenge old dogmas about PcG biological and molecular functions. In this review, we analyse these new data in the context of the old knowledge, highlighting the controversies and providing new models of interpretation and ideas that will perhaps bring some order among apparently contradicting observations.
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Affiliation(s)
- Andrea Scelfo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
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92
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Berke L, Snel B. The histone modification H3K27me3 is retained after gene duplication and correlates with conserved noncoding sequences in Arabidopsis. Genome Biol Evol 2014; 6:572-9. [PMID: 24567304 PMCID: PMC3971591 DOI: 10.1093/gbe/evu040] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The histone modification H3K27me3 is involved in repression of transcription and plays a crucial role in developmental transitions in both animals and plants. It is deposited by PRC2 (Polycomb repressive complex 2), a conserved protein complex. In Arabidopsis thaliana, H3K27me3 is found at 15% of all genes. These tend to encode transcription factors and other regulators important for development. However, it is not known how PRC2 is recruited to target loci nor how this set of target genes arose during Arabidopsis evolution. To resolve the latter, we integrated A. thaliana gene families with five independent genome-wide H3K27me3 data sets. Gene families were either significantly enriched or depleted of H3K27me3, showing a strong impact of shared ancestry to H3K27me3 distribution. To quantify this, we performed ancestral state reconstruction of H3K27me3 on phylogenetic trees of gene families. The set of H3K27me3-marked genes changed less than expected by chance, suggesting that H3K27me3 was retained after gene duplication. This retention suggests that the PRC2-recruiting signal could be encoded in the DNA and also conserved among certain duplicated genes. Indeed, H3K27me3-marked genes were overrepresented among paralogs sharing conserved noncoding sequences (CNSs) that are enriched with transcription factor binding sites. The association of upstream CNSs with H3K27me3-marked genes represents the first genome-wide connection between H3K27me3 and potential regulatory elements in plants. Thus, we propose that CNSs likely function as part of the PRC2 recruitment in plants.
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Affiliation(s)
- Lidija Berke
- Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, The Netherlands
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93
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Short sequences can efficiently recruit histone H3 lysine 27 trimethylation in the absence of enhancer activity and DNA methylation. Proc Natl Acad Sci U S A 2014; 111:E3415-21. [PMID: 25092339 DOI: 10.1073/pnas.1400672111] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Trimethylation of histone H3 at lysine 27 (H3K27me3) is a chromatin mark associated with Polycomb-mediated gene repression. Despite its critical role in development, it remains largely unclear how this mark is targeted to defined loci in mammalian cells. Here, we use iterative genome editing to identify small DNA sequences capable of autonomously recruiting Polycomb. We inserted 28 DNA elements at a defined chromosomal position in mouse embryonic stem cells and assessed their ability to promote H3K27me3 deposition. Combined with deletion analysis, we identified DNA elements as short as 220 nucleotides that correctly recapitulate endogenous H3K27me3 patterns. Functional Polycomb recruiter sequences are invariably CpG-rich but require protection against DNA methylation. Alternatively, their activity can be blocked by placement of an active promoter-enhancer pair in cis. Taken together, these data support the model whereby PRC2 recruitment at specific targets in mammals is positively regulated by local CpG density yet obstructed by transcriptional activity or DNA methylation.
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94
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Gaarenstroom T, Hill CS. TGF-β signaling to chromatin: how Smads regulate transcription during self-renewal and differentiation. Semin Cell Dev Biol 2014; 32:107-18. [PMID: 24503509 DOI: 10.1016/j.semcdb.2014.01.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/29/2014] [Indexed: 12/20/2022]
Abstract
Ligands of the TGF-β superfamily (including the TGF-βs, Nodal and BMPs) play instructive roles during embryonic development. This is achieved by regulation of genes important for both maintaining pluripotency and germ layer specification and differentiation. Here we review how the TGF-β superfamily ligands signal to the chromatin to regulate transcription during development. The effectors of the pathway, the Smad transcription factors, are regulated in a combinatorial and spatiotemporal manner. This occurs via post-translational modifications affecting stability, localization and activity, as well as through interactions with other transcription factors and chromatin modifying enzymes, which occur on DNA. Expression profiling and Chromatin Immunoprecipitation have defined Smad target genes and binding sites on a genome-wide scale, which vary between cell types and differentiation stages. This has led to the insight that Smad-mediated transcriptional responses are influenced by the presence of master transcription factors, such as OCT4, SOX2 and NANOG in embryonic stem cells, interaction with other signal-induced factors, as well as by the general chromatin remodeling machinery. Interplay with transcriptional repressors and the polycomb group proteins also regulates the balance between expression of self-renewal and mesendoderm-specific genes in embryonic stem cells and during early development.
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Affiliation(s)
- Tessa Gaarenstroom
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
| | - Caroline S Hill
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom.
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95
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Riising EM, Comet I, Leblanc B, Wu X, Johansen JV, Helin K. Gene silencing triggers polycomb repressive complex 2 recruitment to CpG islands genome wide. Mol Cell 2014; 55:347-60. [PMID: 24999238 DOI: 10.1016/j.molcel.2014.06.005] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 04/14/2014] [Accepted: 05/28/2014] [Indexed: 01/24/2023]
Abstract
Polycomb group (PcG) proteins are required for normal differentiation and development and are frequently deregulated in cancer. PcG proteins are involved in gene silencing; however, their role in initiation and maintenance of transcriptional repression is not well defined. Here, we show that knockout of the Polycomb repressive complex 2 (PRC2) does not lead to significant gene expression changes in mouse embryonic stem cells (mESCs) and that it is dispensable for initiating silencing of target genes during differentiation. Transcriptional inhibition in mESCs is sufficient to induce genome-wide ectopic PRC2 recruitment to endogenous PcG target genes found in other tissues. PRC2 binding analysis shows that it is restricted to nucleosome-free CpG islands (CGIs) of untranscribed genes. Our results show that it is the transcriptional state that governs PRC2 binding, and we propose that it binds by default to nontranscribed CGI genes to maintain their silenced state and to protect cell identity.
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Affiliation(s)
- Eva Madi Riising
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Itys Comet
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Benjamin Leblanc
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (DanStem), Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Xudong Wu
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Jens Vilstrup Johansen
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; The Bioinformatics Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark; The Danish Stem Cell Center (DanStem), Blegdamsvej 3, 2200 Copenhagen, Denmark.
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96
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Blackledge NP, Farcas AM, Kondo T, King HW, McGouran JF, Hanssen LLP, Ito S, Cooper S, Kondo K, Koseki Y, Ishikura T, Long HK, Sheahan TW, Brockdorff N, Kessler BM, Koseki H, Klose RJ. Variant PRC1 complex-dependent H2A ubiquitylation drives PRC2 recruitment and polycomb domain formation. Cell 2014; 157:1445-1459. [PMID: 24856970 PMCID: PMC4048464 DOI: 10.1016/j.cell.2014.05.004] [Citation(s) in RCA: 539] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/10/2014] [Accepted: 05/02/2014] [Indexed: 11/30/2022]
Abstract
Chromatin modifying activities inherent to polycomb repressive complexes PRC1 and PRC2 play an essential role in gene regulation, cellular differentiation, and development. However, the mechanisms by which these complexes recognize their target sites and function together to form repressive chromatin domains remain poorly understood. Recruitment of PRC1 to target sites has been proposed to occur through a hierarchical process, dependent on prior nucleation of PRC2 and placement of H3K27me3. Here, using a de novo targeting assay in mouse embryonic stem cells we unexpectedly discover that PRC1-dependent H2AK119ub1 leads to recruitment of PRC2 and H3K27me3 to effectively initiate a polycomb domain. This activity is restricted to variant PRC1 complexes, and genetic ablation experiments reveal that targeting of the variant PCGF1/PRC1 complex by KDM2B to CpG islands is required for normal polycomb domain formation and mouse development. These observations provide a surprising PRC1-dependent logic for PRC2 occupancy at target sites in vivo.
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Affiliation(s)
- Neil P Blackledge
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Anca M Farcas
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Takashi Kondo
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Hamish W King
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Joanna F McGouran
- Ubiquitin Proteolysis Group, Central Proteomics Facility, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7BN, UK
| | - Lars L P Hanssen
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Shinsuke Ito
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Sarah Cooper
- Laboratory of Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Kaori Kondo
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Yoko Koseki
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Tomoyuki Ishikura
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Hannah K Long
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Thomas W Sheahan
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Neil Brockdorff
- Laboratory of Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Benedikt M Kessler
- Ubiquitin Proteolysis Group, Central Proteomics Facility, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, OX3 7BN, UK
| | - Haruhiko Koseki
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Robert J Klose
- Laboratory of Chromatin Biology and Transcription, Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
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97
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Targeting polycomb to pericentric heterochromatin in embryonic stem cells reveals a role for H2AK119u1 in PRC2 recruitment. Cell Rep 2014; 7:1456-1470. [PMID: 24857660 PMCID: PMC4062935 DOI: 10.1016/j.celrep.2014.04.012] [Citation(s) in RCA: 243] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 03/12/2014] [Accepted: 04/11/2014] [Indexed: 11/24/2022] Open
Abstract
The mechanisms by which the major Polycomb group (PcG) complexes PRC1 and PRC2 are recruited to target sites in vertebrate cells are not well understood. Building on recent studies that determined a reciprocal relationship between DNA methylation and Polycomb activity, we demonstrate that, in methylation-deficient embryonic stem cells (ESCs), CpG density combined with antagonistic effects of H3K9me3 and H3K36me3 redirects PcG complexes to pericentric heterochromatin and gene-rich domains. Surprisingly, we find that PRC1-linked H2A monoubiquitylation is sufficient to recruit PRC2 to chromatin in vivo, suggesting a mechanism through which recognition of unmethylated CpG determines the localization of both PRC1 and PRC2 at canonical and atypical target sites. We discuss our data in light of emerging evidence suggesting that PcG recruitment is a default state at licensed chromatin sites, mediated by interplay between CpG hypomethylation and counteracting H3 tail modifications. Absence of DNA methylation recruits Polycomb complexes to pericentric heterochromatin H3K9me3 antagonizes activity of PRC2, but not PRC1, at pericentric heterochromatin CpG density and antagonism by H3 modifications define genome-wide Polycomb occupancy PRC1-mediated H2AK119u1 recruits PRC2 and H3K27me3
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98
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Understanding the relationship between DNA methylation and histone lysine methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1362-72. [PMID: 24560929 PMCID: PMC4316174 DOI: 10.1016/j.bbagrm.2014.02.007] [Citation(s) in RCA: 352] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/11/2014] [Indexed: 12/19/2022]
Abstract
DNA methylation acts as an epigenetic modification in vertebrate DNA. Recently it has become clear that the DNA and histone lysine methylation systems are highly interrelated and rely mechanistically on each other for normal chromatin function in vivo. Here we examine some of the functional links between these systems, with a particular focus on several recent discoveries suggesting how lysine methylation may help to target DNA methylation during development, and vice versa. In addition, the emerging role of non-methylated DNA found in CpG islands in defining histone lysine methylation profiles at gene regulatory elements will be discussed in the context of gene regulation. This article is part of a Special Issue entitled: Methylation: A Multifaceted Modification — looking at transcription and beyond. There is an emerging realisation that DNA and histone lysine methylation in mammals are highly interrelated. Targeting of DNA methylation is mechanistically linked to H3K9 methylation. Uhrf1 acts as a link between H3K9 methylation and maintenance methylation during DNA replication. Targeting of Dnmt3a/b is influenced by H3K4 and H3K36 methylation. Non-methylated DNA at CpG islands influences histone methylation through ZF-CxxC proteins.
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99
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Jarid2 Is Implicated in the Initial Xist-Induced Targeting of PRC2 to the Inactive X Chromosome. Mol Cell 2014; 53:301-16. [DOI: 10.1016/j.molcel.2014.01.002] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/16/2013] [Accepted: 12/24/2013] [Indexed: 12/16/2022]
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100
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He C, Huang H, Xu L. Mechanisms guiding Polycomb activities during gene silencing in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2013; 4:454. [PMID: 24312106 PMCID: PMC3826153 DOI: 10.3389/fpls.2013.00454] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/23/2013] [Indexed: 05/22/2023]
Abstract
Polycomb group (PcG) proteins act in an evolutionarily conserved epigenetic pathway that regulates chromatin structures in plants and animals, repressing many developmentally important genes by modifying histones. PcG proteins can form at least two multiprotein complexes: Polycomb Repressive Complexes 1 and 2 (PRC1 and PRC2, respectively). The functions of Arabidopsis thaliana PRCs have been characterized in multiple stages of development and have diverse roles in response to environmental stimuli. Recently, the mechanism that precisely regulates Arabidopsis PcG activity was extensively studied. In this review, we summarize recent discoveries in the regulations of PcG at the three different layers: the recruitment of PRCs to specific target loci, the polyubiquitination and degradation of PRC2, and the antagonism of PRC2 activity by the Trithorax group proteins. Current knowledge indicates that the powerful activity of the PcG pathway is strictly controlled for specific silencing of target genes during plant development and in response to environmental stimuli.
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Affiliation(s)
| | | | - Lin Xu
- *Correspondence: Lin Xu, National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China e-mail:
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