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The binding of Chp2's chromodomain to methylated H3K9 is essential for Chp2's role in heterochromatin assembly in fission yeast. PLoS One 2018; 13:e0201101. [PMID: 30110338 PMCID: PMC6093649 DOI: 10.1371/journal.pone.0201101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 07/09/2018] [Indexed: 12/19/2022] Open
Abstract
The binding of heterochromatin protein 1 (HP1) to lysine 9–methylated histone H3 (H3K9me) is an essential step in heterochromatin assembly. Chp2, an HP1-family protein in the fission yeast Schizosaccharomyces pombe, is required for heterochromatic silencing. Chp2 recruits SHREC, a multifunctional protein complex containing the nucleosome remodeler Mit1 and the histone deacetylase Clr3. Although the targeting of SHREC to chromatin is thought to occur via two distinct modules regulated by the SHREC components Chp2 and Clr2, it is not clear how Chp2’s chromatin binding regulates SHREC function. Here, we show that H3K9me binding by Chp2’s chromodomain (CD) is essential for Chp2’s silencing function and for SHREC’s targeting to chromatin. Cells expressing a Chp2 mutant with defective H3K9me binding (Chp2-W199A) have a silencing defect, with a phenotype similar to that of chp2-null cells. Genetic analysis using a synthetic silencing system revealed that a Chp2 mutant and SHREC-component mutants had similar phenotypes, suggesting that Chp2’s function also affects SHREC’s chromatin binding. Size-exclusion chromatography of native protein complexes showed that Chp2-CD’s binding of H3K9me3 ensures Clr3’s chromatin binding, and suggested that SHREC’s chromatin binding is mediated by separable functional modules. Interestingly, we found that the stability of the Chp2 protein depended on the Clr3 protein’s histone deacetylase activity. Our findings demonstrate that Chp2’s H3K9me binding is critical for SHREC function and that the two modules within the SHREC complex are interdependent.
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Hurel A, Phillips D, Vrielynck N, Mézard C, Grelon M, Christophorou N. A cytological approach to studying meiotic recombination and chromosome dynamics in Arabidopsis thaliana male meiocytes in three dimensions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:385-396. [PMID: 29681056 DOI: 10.1111/tpj.13942] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 05/18/2023]
Abstract
During meiotic prophase I chromosomes undergo dramatic conformational changes that accompany chromosome condensation, pairing and recombination between homologs. These changes include the anchoring of telomeres to the nuclear envelope and their clustering to form a bouquet. In plants, these events have been studied and illustrated in intact meiocytes of species with large genomes. Arabidopsis thaliana is an excellent genetic model in which major molecular pathways that control synapsis and recombination between homologs have been uncovered. Yet the study of chromosome dynamics is hampered by current cytological methods that disrupt the three-dimensional (3D) architecture of the nucleus. Here we set up a protocol to preserve the 3D configuration of A. thaliana meiocytes. We showed that this technique is compatible with the use of a variety of antibodies that label structural and recombination proteins and were able to highlight the presence of clustered synapsis initiation centers at the nuclear periphery. By using fluorescence in situ hybridization we also studied the behavior of chromosomes during pre-meiotic G2 and prophase I, revealing the existence of a telomere bouquet during A. thaliana male meiosis. In addition we showed that the number of telomeres in a bouquet and its volume vary greatly, thus revealing the complexity of telomere behavior during meiotic prophase I. Finally, by using probes that label subtelomeric regions of individual chromosomes, we revealed differential localization behaviors of chromosome ends. Our protocol opens new areas of research for investigating chromosome dynamics in A. thaliana meiocytes.
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Affiliation(s)
- Aurélie Hurel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France
| | - Dylan Phillips
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA, UK
| | - Nathalie Vrielynck
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France
| | - Christine Mézard
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France
| | - Mathilde Grelon
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France
| | - Nicolas Christophorou
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026, Versailles Cedex, France
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Perovanovic J, Dell'Orso S, Gnochi VF, Jaiswal JK, Sartorelli V, Vigouroux C, Mamchaoui K, Mouly V, Bonne G, Hoffman EP. Laminopathies disrupt epigenomic developmental programs and cell fate. Sci Transl Med 2017; 8:335ra58. [PMID: 27099177 DOI: 10.1126/scitranslmed.aad4991] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/28/2016] [Indexed: 12/12/2022]
Abstract
The nuclear envelope protein lamin A is encoded by thelamin A/C(LMNA) gene, which can contain missense mutations that cause Emery-Dreifuss muscular dystrophy (EDMD) (p.R453W). We fused mutated forms of the lamin A protein to bacterial DNA adenine methyltransferase (Dam) to define euchromatic-heterochromatin (epigenomic) transitions at the nuclear envelope during myogenesis (using DamID-seq). Lamin A missense mutations disrupted appropriate formation of lamin A-associated heterochromatin domains in an allele-specific manner-findings that were confirmed by chromatin immunoprecipitation-DNA sequencing (ChIP-seq) in murine H2K cells and DNA methylation studies in fibroblasts from muscular dystrophy patient who carried a distinctLMNAmutation (p.H222P). Observed perturbations of the epigenomic transitions included exit from pluripotency and cell cycle programs [euchromatin (open, transcribed) to heterochromatin (closed, silent)], as well as induction of myogenic loci (heterochromatin to euchromatin). In muscle biopsies from patients with either a gain- or change-of-functionLMNAgene mutation or a loss-of-function mutation in theemeringene, both of which cause EDMD, we observed inappropriate loss of heterochromatin formation at theSox2pluripotency locus, which was associated with persistent mRNA expression ofSox2 Overexpression ofSox2inhibited myogenic differentiation in human immortalized myoblasts. Our findings suggest that nuclear envelopathies are disorders of developmental epigenetic programming that result from altered formation of lamina-associated domains.
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Affiliation(s)
- Jelena Perovanovic
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Stefania Dell'Orso
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Viola F Gnochi
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
| | - Jyoti K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA
| | - Vittorio Sartorelli
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Corinne Vigouroux
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires, F-75012 Paris, France. INSERM UMR_S938, Centre de Recherche Saint-Antoine, F-75012 Paris, France. Sorbonne Universités, UPMC (Université Pierre et Marie Curie) Univ Paris 06, UMR_S938, F-75005 Paris, France. ICAN (Institute of Cardiometabolism and Nutrition), F-75013 Paris, France
| | - Kamel Mamchaoui
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Vincent Mouly
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Gisèle Bonne
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, F-75013 Paris, France
| | - Eric P Hoffman
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA. Department of Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20010, USA.
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