1
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Downs JA, Gasser SM. Chromatin remodeling and spatial concerns in DNA double-strand break repair. Curr Opin Cell Biol 2024; 90:102405. [PMID: 39083951 DOI: 10.1016/j.ceb.2024.102405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/07/2024] [Accepted: 07/11/2024] [Indexed: 08/02/2024]
Abstract
The substrate for the repair of DNA damage in living cells is not DNA but chromatin. Chromatin bears a range of modifications, which in turn bind ligands that compact or open chromatin structure, and determine its spatial organization within the nucleus. In some cases, RNA in the form of RNA:DNA hybrids or R-loops modulates DNA accessibility. Each of these parameters can favor particular pathways of repair. Chromatin or nucleosome remodelers are key regulators of chromatin structure, and a number of remodeling complexes are implicated in DNA repair. We cover novel insights into the impact of chromatin structure, nuclear organization, R-loop formation, nuclear actin, and nucleosome remodelers in DNA double-strand break repair, focusing on factors that alter repair functional upon ablation.
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Affiliation(s)
- Jessica A Downs
- Epigenetics and Genome Stability Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Susan M Gasser
- ISREC Foundation, and University of Lausanne, Agora Cancer Research Center, Rue du Bugnon 25a, 1005 Lausanne, Switzerland.
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2
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Baier AS, Peterson CL. Fluorescence approaches for biochemical analysis of ATP-dependent chromatin remodeling enzymes. Methods Enzymol 2022; 673:1-17. [PMID: 35965003 PMCID: PMC10107425 DOI: 10.1016/bs.mie.2022.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The dynamic nature of chromatin is an essential mechanism by which gene expression is regulated. Chromatin is comprised of nucleosomes, an octamer of histone proteins wrapped by DNA, and manipulation of these structures is carried out by a family of proteins known as ATP-dependent chromatin remodeling enzymes. These enzymes carry out a diverse range of activities, from appropriately positioning and adjusting the density of nucleosomes on genes, to installation and removal of histones for sequence variants, to ejection from DNA. These activities have a critical role in the proper maintenance of chromatin architecture, and dysregulation of chromatin remodeling is directly linked to the pathophysiology of various diseases. Mechanistic understanding of chromatin remodeling enzymes is therefore desirable, both as the drivers of this essential cellular activity and as potentially novel therapeutic targets in disease. In this chapter we cover our current methods for characterization of remodeler substrate binding affinity and catalytic activity, leveraging fluorescence polarization and Förster resonance energy transfer assays.
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3
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Jian Y, Shim WB, Ma Z. Multiple functions of SWI/SNF chromatin remodeling complex in plant-pathogen interactions. STRESS BIOLOGY 2021; 1:18. [PMID: 37676626 PMCID: PMC10442046 DOI: 10.1007/s44154-021-00019-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 11/22/2021] [Indexed: 09/08/2023]
Abstract
The SWI/SNF chromatin remodeling complex utilizes the energy of ATP hydrolysis to facilitate chromatin access and plays essential roles in DNA-based events. Studies in animals, plants and fungi have uncovered sophisticated regulatory mechanisms of this complex that govern development and various stress responses. In this review, we summarize the composition of SWI/SNF complex in eukaryotes and discuss multiple functions of the SWI/SNF complex in regulating gene transcription, mRNA splicing, and DNA damage response. Our review further highlights the importance of SWI/SNF complex in regulating plant immunity responses and fungal pathogenesis. Finally, the potentials in exploiting chromatin remodeling for management of crop disease are presented.
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Affiliation(s)
- Yunqing Jian
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China.
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4
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Zhang S, Zhou T, Wang Z, Yi F, Li C, Guo W, Xu H, Cui H, Dong X, Liu J, Song X, Cao L. Post-Translational Modifications of PCNA in Control of DNA Synthesis and DNA Damage Tolerance-the Implications in Carcinogenesis. Int J Biol Sci 2021; 17:4047-4059. [PMID: 34671219 PMCID: PMC8495385 DOI: 10.7150/ijbs.64628] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/19/2021] [Indexed: 11/05/2022] Open
Abstract
The faithful DNA replication is a critical event for cell survival and inheritance. However, exogenous or endogenous sources of damage challenge the accurate synthesis of DNA, which causes DNA lesions. The DNA lesions are obstacles for replication fork progression. However, the prolonged replication fork stalling leads to replication fork collapse, which may cause DNA double-strand breaks (DSB). In order to maintain genomic stability, eukaryotic cells evolve translesion synthesis (TLS) and template switching (TS) to resolve the replication stalling. Proliferating cell nuclear antigen (PCNA) trimer acts as a slide clamp and encircles DNA to orchestrate DNA synthesis and DNA damage tolerance (DDT). The post-translational modifications (PTMs) of PCNA regulate these functions to ensure the appropriate initiation and termination of replication and DDT. The aberrant regulation of PCNA PTMs will result in DSB, which causes mutagenesis and poor response to chemotherapy. Here, we review the roles of the PCNA PTMs in DNA duplication and DDT. We propose that clarifying the regulation of PCNA PTMs may provide insights into understanding the development of cancers.
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Affiliation(s)
- Siyi Zhang
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Tingting Zhou
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Zhuo Wang
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Fei Yi
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Chunlu Li
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Wendong Guo
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Hongde Xu
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Hongyan Cui
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Xiang Dong
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Jingwei Liu
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Xiaoyu Song
- Institute of Health Sciences, China Medical University, Shenyang, Liaoning Province, 110122, PR China
| | - Liu Cao
- College of Basic Medical Science, Key Laboratory of Cell Biology of Ministry of Public Health, Key Laboratory of Medical Cell Biology of Ministry of Education, Liaoning Province Collaborative Innovation Center of Aging Related Disease Diagnosis and Treatment and Prevention, China Medical University, Shenyang, Liaoning Province, 110122, PR China
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5
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A Conserved Histone H3-H4 Interface Regulates DNA Damage Tolerance and Homologous Recombination during the Recovery from Replication Stress. Mol Cell Biol 2021; 41:MCB.00044-20. [PMID: 33526454 DOI: 10.1128/mcb.00044-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 01/24/2021] [Indexed: 12/20/2022] Open
Abstract
In eukaryotes, genomic DNA is packaged into nucleosomes, which are the basal components coordinating both the structures and functions of chromatin. In this study, we screened a collection of mutations for histone H3/H4 mutants in Saccharomyces cerevisiae that affect the DNA damage sensitivity of DNA damage tolerance (DDT)-deficient cells. We identified a class of histone H3/H4 mutations that suppress methyl methanesulfonate (MMS) sensitivity of DDT-deficient cells (referred to here as the histone SDD mutations), which likely cluster on a specific H3-H4 interface of the nucleosomes. The histone SDD mutations did not suppress the MMS sensitivity of DDT-deficient cells in the absence of Rad51, indicating that homologous recombination (HR) is responsible for DNA damage resistance. Furthermore, the histone SDD mutants showed reduced levels of PCNA ubiquitination after exposure to MMS or UV irradiation, consistent with decreased MMS-induced mutagenesis relative to that of wild-type cells. We also found that histone SDD mutants lacking the INO80 chromatin remodeler impair HR-dependent recovery from MMS-induced replication arrest, resulting in defective S-phase progression and increased Rad52 foci. Taken together, our data provide novel insights into nucleosome functions, which link INO80-dependent chromatin remodeling to the regulation of DDT and HR during the recovery from replication blockage.
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6
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Aleksandrov R, Hristova R, Stoynov S, Gospodinov A. The Chromatin Response to Double-Strand DNA Breaks and Their Repair. Cells 2020; 9:cells9081853. [PMID: 32784607 PMCID: PMC7464352 DOI: 10.3390/cells9081853] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 02/07/2023] Open
Abstract
Cellular DNA is constantly being damaged by numerous internal and external mutagenic factors. Probably the most severe type of insults DNA could suffer are the double-strand DNA breaks (DSBs). They sever both DNA strands and compromise genomic stability, causing deleterious chromosomal aberrations that are implicated in numerous maladies, including cancer. Not surprisingly, cells have evolved several DSB repair pathways encompassing hundreds of different DNA repair proteins to cope with this challenge. In eukaryotic cells, DSB repair is fulfilled in the immensely complex environment of the chromatin. The chromatin is not just a passive background that accommodates the multitude of DNA repair proteins, but it is a highly dynamic and active participant in the repair process. Chromatin alterations, such as changing patterns of histone modifications shaped by numerous histone-modifying enzymes and chromatin remodeling, are pivotal for proficient DSB repair. Dynamic chromatin changes ensure accessibility to the damaged region, recruit DNA repair proteins, and regulate their association and activity, contributing to DSB repair pathway choice and coordination. Given the paramount importance of DSB repair in tumorigenesis and cancer progression, DSB repair has turned into an attractive target for the development of novel anticancer therapies, some of which have already entered the clinic.
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7
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Chabanon RM, Morel D, Postel-Vinay S. Exploiting epigenetic vulnerabilities in solid tumors: Novel therapeutic opportunities in the treatment of SWI/SNF-defective cancers. Semin Cancer Biol 2019; 61:180-198. [PMID: 31568814 DOI: 10.1016/j.semcancer.2019.09.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022]
Abstract
Mammalian switch/sucrose non-fermentable (mSWI/SNF) family complexes are pivotal elements of the chromatin remodeling machinery, which contribute to the regulation of several major cellular functions. Large-scale exome-wide sequencing studies have identified mutations in genes encoding mSWI/SNF subunits in 20% of all human cancers, establishing mSWI/SNF deficiency as a recurrent oncogenic alteration. Accumulating evidence now supports that several mSWI/SNF defects represent targetable vulnerabilities in cancer; notably, recent research advances have unveiled unexpected synthetic lethal opportunities that foster the development of novel biomarker-driven and mechanism-based therapeutic approaches for the treatment of mSWI/SNF-deficient tumors. Here, we review the latest breakthroughs and discoveries that inform our understanding of the mSWI/SNF complexes biology in carcinogenesis, and discuss the most promising therapeutic strategies to target mSWI/SNF defects in human solid malignancies.
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Affiliation(s)
- Roman M Chabanon
- Université Paris Saclay, Université Paris-Sud, Faculté de médicine, Le Kremlin Bicêtre, France; ATIP-Avenir Group, Inserm Unit U981, Gustave Roussy, Villejuif, France; The Breast Cancer Now Toby Robins Breast Cancer Research Centre, France; CRUK Gene Function Laboratory, The Institute of Cancer Research, London, United Kingdom
| | - Daphné Morel
- Université Paris Saclay, Université Paris-Sud, Faculté de médicine, Le Kremlin Bicêtre, France; ATIP-Avenir Group, Inserm Unit U981, Gustave Roussy, Villejuif, France
| | - Sophie Postel-Vinay
- Université Paris Saclay, Université Paris-Sud, Faculté de médicine, Le Kremlin Bicêtre, France; ATIP-Avenir Group, Inserm Unit U981, Gustave Roussy, Villejuif, France; DITEP (Département d'Innovations Thérapeutiques et Essais Précoces), Gustave Roussy, Villejuif, France.
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8
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Faridounnia M, Folkers GE, Boelens R. Function and Interactions of ERCC1-XPF in DNA Damage Response. Molecules 2018; 23:E3205. [PMID: 30563071 PMCID: PMC6320978 DOI: 10.3390/molecules23123205] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/27/2018] [Accepted: 12/01/2018] [Indexed: 12/28/2022] Open
Abstract
Numerous proteins are involved in the multiple pathways of the DNA damage response network and play a key role to protect the genome from the wide variety of damages that can occur to DNA. An example of this is the structure-specific endonuclease ERCC1-XPF. This heterodimeric complex is in particular involved in nucleotide excision repair (NER), but also in double strand break repair and interstrand cross-link repair pathways. Here we review the function of ERCC1-XPF in various DNA repair pathways and discuss human disorders associated with ERCC1-XPF deficiency. We also overview our molecular and structural understanding of XPF-ERCC1.
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Affiliation(s)
- Maryam Faridounnia
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Gert E Folkers
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
| | - Rolf Boelens
- Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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9
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Swygert SG, Senapati S, Bolukbasi MF, Wolfe SA, Lindsay S, Peterson CL. SIR proteins create compact heterochromatin fibers. Proc Natl Acad Sci U S A 2018; 115:12447-12452. [PMID: 30455303 PMCID: PMC6298083 DOI: 10.1073/pnas.1810647115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is a silenced chromatin region essential for maintaining genomic stability and driving developmental processes. The complicated structure and dynamics of heterochromatin have rendered it difficult to characterize. In budding yeast, heterochromatin assembly requires the SIR proteins-Sir3, believed to be the primary structural component of SIR heterochromatin, and the Sir2-4 complex, responsible for the targeted recruitment of SIR proteins and the deacetylation of lysine 16 of histone H4. Previously, we found that Sir3 binds but does not compact nucleosomal arrays. Here we reconstitute chromatin fibers with the complete complement of SIR proteins and use sedimentation velocity, molecular modeling, and atomic force microscopy to characterize the stoichiometry and conformation of SIR chromatin fibers. In contrast to fibers with Sir3 alone, our results demonstrate that SIR arrays are highly compact. Strikingly, the condensed structure of SIR heterochromatin fibers requires both the integrity of H4K16 and an interaction between Sir3 and Sir4. We propose a model in which a dimer of Sir3 bridges and stabilizes two adjacent nucleosomes, while a Sir2-4 heterotetramer interacts with Sir3 associated with a nucleosomal trimer, driving fiber compaction.
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Affiliation(s)
- Sarah G Swygert
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Subhadip Senapati
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Mehmet F Bolukbasi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Scot A Wolfe
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Stuart Lindsay
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605;
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10
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Caridi PC, Delabaere L, Zapotoczny G, Chiolo I. And yet, it moves: nuclear and chromatin dynamics of a heterochromatic double-strand break. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0291. [PMID: 28847828 PMCID: PMC5577469 DOI: 10.1098/rstb.2016.0291] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2017] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is mostly composed of repeated DNA sequences prone to aberrant recombination. How cells maintain the stability of these sequences during double-strand break (DSB) repair has been a long-standing mystery. Studies in Drosophila cells revealed that faithful homologous recombination repair of heterochromatic DSBs relies on the striking relocalization of repair sites to the nuclear periphery before Rad51 recruitment and repair progression. Here, we summarize our current understanding of this response, including the molecular mechanisms involved, and conserved pathways in mammalian cells. We will highlight important similarities with pathways identified in budding yeast for repair of other types of repeated sequences, including rDNA and short telomeres. We will also discuss the emerging role of chromatin composition and regulation in heterochromatin repair progression. Together, these discoveries challenged previous assumptions that repair sites are substantially static in multicellular eukaryotes, that heterochromatin is largely inert in the presence of DSBs, and that silencing and compaction in this domain are obstacles to repair. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.
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Affiliation(s)
- P Christopher Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
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11
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Rother MB, van Attikum H. DNA repair goes hip-hop: SMARCA and CHD chromatin remodellers join the break dance. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0285. [PMID: 28847822 PMCID: PMC5577463 DOI: 10.1098/rstb.2016.0285] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2017] [Indexed: 12/20/2022] Open
Abstract
Proper signalling and repair of DNA double-strand breaks (DSB) is critical to prevent genome instability and diseases such as cancer. The packaging of DNA into chromatin, however, has evolved as a mere obstacle to these DSB responses. Posttranslational modifications and ATP-dependent chromatin remodelling help to overcome this barrier by modulating nucleosome structures and allow signalling and repair machineries access to DSBs in chromatin. Here we recap our current knowledge on how ATP-dependent SMARCA- and CHD-type chromatin remodellers alter chromatin structure during the signalling and repair of DSBs and discuss how their dysfunction impacts genome stability and human disease. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.
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Affiliation(s)
- Magdalena B Rother
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
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12
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Poli J, Gasser SM, Papamichos-Chronakis M. The INO80 remodeller in transcription, replication and repair. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0290. [PMID: 28847827 DOI: 10.1098/rstb.2016.0290] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2017] [Indexed: 02/06/2023] Open
Abstract
The accessibility of eukaryotic genomes to the action of enzymes involved in transcription, replication and repair is maintained despite the organization of DNA into nucleosomes. This access is often regulated by the action of ATP-dependent nucleosome remodellers. The INO80 class of nucleosome remodellers has unique structural features and it is implicated in a diverse array of functions, including transcriptional regulation, DNA replication and DNA repair. Underlying these diverse functions is the catalytic activity of the main ATPase subunit, which in the context of a multisubunit complex can shift nucleosomes and carry out histone dimer exchange. In vitro studies showed that INO80 promotes replication fork progression on a chromatin template, while in vivo it was shown to facilitate replication fork restart after stalling and to help evict RNA polymerase II at transcribed genes following the collision of a replication fork with transcription. More recent work in yeast implicates INO80 in the general eviction and degradation of nucleosomes following high doses of oxidative DNA damage. Beyond these replication and repair functions, INO80 was shown to repress inappropriate transcription at promoters in the opposite direction to the coding sequence. Here we discuss the ways in which INO80's diverse functions help maintain genome integrity.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Jérôme Poli
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.,University of Montpellier and Centre de Recherche en Biologie Cellulaire (CRBM), UMR5237, CNRS, Montpellier 34095, Cedex 5, France
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland .,Faculty of Natural Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Manolis Papamichos-Chronakis
- Institute for Cell and Molecular Biosciences, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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13
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Fortuny A, Polo SE. The response to DNA damage in heterochromatin domains. Chromosoma 2018; 127:291-300. [PMID: 29594515 PMCID: PMC6440646 DOI: 10.1007/s00412-018-0669-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 10/24/2022]
Abstract
Eukaryotic genomes are organized into chromatin, divided into structurally and functionally distinct euchromatin and heterochromatin compartments. The high level of compaction and the abundance of repeated sequences in heterochromatin pose multiple challenges for the maintenance of genome stability. Cells have evolved sophisticated and highly controlled mechanisms to overcome these constraints. Here, we summarize recent findings on how the heterochromatic state influences DNA damage formation, signaling, and repair. By focusing on distinct heterochromatin domains in different eukaryotic species, we highlight the heterochromatin contribution to the compartmentalization of DNA damage repair in the cell nucleus and to the repair pathway choice. We also describe the diverse chromatin alterations associated with the DNA damage response in heterochromatin domains and present our current understanding of their regulatory mechanisms. Finally, we discuss the biological significance and the evolutionary conservation of these processes.
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Affiliation(s)
- Anna Fortuny
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Paris Diderot University, Paris, France
| | - Sophie E Polo
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Paris Diderot University, Paris, France.
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14
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Sieverman KJ, Rine J. Impact of Homologous Recombination on Silent Chromatin in Saccharomyces cerevisiae. Genetics 2018; 208:1099-1113. [PMID: 29339409 PMCID: PMC5844325 DOI: 10.1534/genetics.118.300704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022] Open
Abstract
Specialized chromatin domains repress transcription of genes within them and present a barrier to many DNA-protein interactions. Silent chromatin in the budding yeast Saccharomyces cerevisiae, akin to heterochromatin of metazoans and plants, inhibits transcription of PolII- and PolIII-transcribed genes, yet somehow grants access to proteins necessary for DNA transactions like replication and homologous recombination. In this study, we adapted a novel assay to detect even transient changes in the dynamics of transcriptional silencing at HML after it served as a template for homologous recombination. Homologous recombination specifically targeted to HML via double-strand-break formation at a homologous locus often led to transient loss of transcriptional silencing at HML Interestingly, many cells could template homology-directed repair at HML without an obligate loss of silencing, even in recombination events with extensive gene conversion tracts. In a population of cells that experienced silencing loss following recombination, transcription persisted for 2-3 hr after all double-strand breaks were repaired. mRNA levels from cells that experienced recombination-induced silencing loss did not approach the amount of mRNA seen in cells lacking transcriptional silencing. Thus, silencing loss at HML after homologous recombination was short-lived and limited.
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Affiliation(s)
- Kathryn J Sieverman
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California at Berkeley, California 94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, University of California at Berkeley, California 94720
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15
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Abstract
Chromatin is organized into higher-order structures that form subcompartments in interphase nuclei. Different categories of specialized enzymes act on chromatin and regulate its compaction and biophysical characteristics in response to physiological conditions. We present an overview of the function of chromatin structure and its dynamic changes in response to genotoxic stress, focusing on both subnuclear organization and the physical mobility of DNA. We review the requirements and mechanisms that cause chromatin relocation, enhanced mobility, and chromatin unfolding as a consequence of genotoxic lesions. An intriguing link has been established recently between enhanced chromatin dynamics and histone loss.
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Affiliation(s)
- Michael H Hauer
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
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16
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Abstract
In modern molecular biology, RNA has emerged as a versatile macromolecule capable of mediating an astonishing number of biological functions beyond its role as a transient messenger of genetic information. The recent discovery and functional analyses of new classes of noncoding RNAs (ncRNAs) have revealed their widespread use in many pathways, including several in the nucleus. This Review focuses on the mechanisms by which nuclear ncRNAs directly contribute to the maintenance of genome stability. We discuss how ncRNAs inhibit spurious recombination among repetitive DNA elements, repress mobilization of transposable elements (TEs), template or bridge DNA double-strand breaks (DSBs) during repair, and direct developmentally regulated genome rearrangements in some ciliates. These studies reveal an unexpected repertoire of mechanisms by which ncRNAs contribute to genome stability and even potentially fuel evolution by acting as templates for genome modification.
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17
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Batté A, Brocas C, Bordelet H, Hocher A, Ruault M, Adjiri A, Taddei A, Dubrana K. Recombination at subtelomeres is regulated by physical distance, double-strand break resection and chromatin status. EMBO J 2017; 36:2609-2625. [PMID: 28754657 DOI: 10.15252/embj.201796631] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 11/09/2022] Open
Abstract
Homologous recombination (HR) is a conserved mechanism that repairs broken chromosomes via intact homologous sequences. How different genomic, chromatin and subnuclear contexts influence HR efficiency and outcome is poorly understood. We developed an assay to assess HR outcome by gene conversion (GC) and break-induced replication (BIR), and discovered that subtelomeric double-stranded breaks (DSBs) are preferentially repaired by BIR despite the presence of flanking homologous sequences. Overexpression of a silencing-deficient SIR3 mutant led to active grouping of telomeres and specifically increased the GC efficiency between subtelomeres. Thus, physical distance limits GC at subtelomeres. However, the repair efficiency between reciprocal intrachromosomal and subtelomeric sequences varies up to 15-fold, depending on the location of the DSB, indicating that spatial proximity is not the only limiting factor for HR EXO1 deletion limited the resection at subtelomeric DSBs and improved GC efficiency. The presence of repressive chromatin at subtelomeric DSBs also favoured recombination, by counteracting EXO1-mediated resection. Thus, repressive chromatin promotes HR at subtelomeric DSBs by limiting DSB resection and protecting against genetic information loss.
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Affiliation(s)
- Amandine Batté
- Institute of Molecular and Cellular Radiobiology, CEA/DRF, Fontenay-aux-Roses cedex, France.,Inserm U967, Fontenay-aux-Roses cedex, France.,Université Paris-Diderot et Université Paris-Sud, UMR967, Fontenay-aux-Roses cedex, France
| | - Clémentine Brocas
- Institute of Molecular and Cellular Radiobiology, CEA/DRF, Fontenay-aux-Roses cedex, France.,Inserm U967, Fontenay-aux-Roses cedex, France.,Université Paris-Diderot et Université Paris-Sud, UMR967, Fontenay-aux-Roses cedex, France
| | - Hélène Bordelet
- Institute of Molecular and Cellular Radiobiology, CEA/DRF, Fontenay-aux-Roses cedex, France.,Inserm U967, Fontenay-aux-Roses cedex, France.,Université Paris-Diderot et Université Paris-Sud, UMR967, Fontenay-aux-Roses cedex, France
| | - Antoine Hocher
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, Paris, France
| | - Myriam Ruault
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, Paris, France
| | - Adouda Adjiri
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, Paris, France
| | - Angela Taddei
- Institut Curie, PSL Research University, CNRS, UMR3664, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR3664, Paris, France
| | - Karine Dubrana
- Institute of Molecular and Cellular Radiobiology, CEA/DRF, Fontenay-aux-Roses cedex, France .,Inserm U967, Fontenay-aux-Roses cedex, France.,Université Paris-Diderot et Université Paris-Sud, UMR967, Fontenay-aux-Roses cedex, France
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18
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The Nuts and Bolts of Transcriptionally Silent Chromatin in Saccharomyces cerevisiae. Genetics 2017; 203:1563-99. [PMID: 27516616 DOI: 10.1534/genetics.112.145243] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/30/2016] [Indexed: 12/31/2022] Open
Abstract
Transcriptional silencing in Saccharomyces cerevisiae occurs at several genomic sites including the silent mating-type loci, telomeres, and the ribosomal DNA (rDNA) tandem array. Epigenetic silencing at each of these domains is characterized by the absence of nearly all histone modifications, including most prominently the lack of histone H4 lysine 16 acetylation. In all cases, silencing requires Sir2, a highly-conserved NAD(+)-dependent histone deacetylase. At locations other than the rDNA, silencing also requires additional Sir proteins, Sir1, Sir3, and Sir4 that together form a repressive heterochromatin-like structure termed silent chromatin. The mechanisms of silent chromatin establishment, maintenance, and inheritance have been investigated extensively over the last 25 years, and these studies have revealed numerous paradigms for transcriptional repression, chromatin organization, and epigenetic gene regulation. Studies of Sir2-dependent silencing at the rDNA have also contributed to understanding the mechanisms for maintaining the stability of repetitive DNA and regulating replicative cell aging. The goal of this comprehensive review is to distill a wide array of biochemical, molecular genetic, cell biological, and genomics studies down to the "nuts and bolts" of silent chromatin and the processes that yield transcriptional silencing.
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19
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McMurchy AN, Stempor P, Gaarenstroom T, Wysolmerski B, Dong Y, Aussianikava D, Appert A, Huang N, Kolasinska-Zwierz P, Sapetschnig A, Miska EA, Ahringer J. A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress. eLife 2017; 6:e21666. [PMID: 28294943 PMCID: PMC5395297 DOI: 10.7554/elife.21666] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 03/10/2017] [Indexed: 12/26/2022] Open
Abstract
Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among factors and pathways underlies the importance of safeguarding the genome through multiple means.
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Affiliation(s)
- Alicia N McMurchy
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Przemyslaw Stempor
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Tessa Gaarenstroom
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Brian Wysolmerski
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Yan Dong
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Darya Aussianikava
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Alex Appert
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Ni Huang
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | | | - Alexandra Sapetschnig
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Eric A Miska
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Julie Ahringer
- The Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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20
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Methods to Study the Atypical Roles of DNA Repair and SMC Proteins in Gene Silencing. Methods Mol Biol 2016. [PMID: 27797079 DOI: 10.1007/978-1-4939-6545-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Silenced heterochromatin influences all nuclear processes including chromosome structure, nuclear organization, transcription, replication, and repair. Proteins that mediate silencing affect all of these nuclear processes. Similarly proteins involved in replication, repair, and chromosome structure play a role in the formation and maintenance of silenced heterochromatin. In this chapter we describe a handful of simple tools and methods that can be used to study the atypical role of proteins in gene silencing.
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21
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Tsabar M, Hicks WM, Tsaponina O, Haber JE. Re-establishment of nucleosome occupancy during double-strand break repair in budding yeast. DNA Repair (Amst) 2016; 47:21-29. [PMID: 27720308 DOI: 10.1016/j.dnarep.2016.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/23/2016] [Accepted: 09/26/2016] [Indexed: 02/02/2023]
Abstract
Homologous recombination (HR) is an evolutionarily conserved pathway in eukaryotes that repairs a double-strand break (DSB) by copying homologous sequences from a sister chromatid, a homologous chromosome or an ectopic location. Recombination is challenged by the packaging of DNA into nucleosomes, which may impair the process at many steps, from resection of the DSB ends to the re-establishement of nucleosomes after repair. However, nucleosome dynamics during DSB repair have not been well described, primarily because of a lack of well-ordered nucleosomes around a DSB. We designed a system in budding yeast Saccharomyces cerevisiae to monitor nucleosome dynamics during repair of an HO endonuclease-induced DSB. Nucleosome occupancy around the break is lost following DSB formation, by 5'-3' resection of the DSB end. Soon after repair is complete, nucleosome occupancy is partially restored in a repair-dependent but cell cycle-independent manner. Full re-establishment of nucleosome protection back to the level prior to DSB induction is achieved when the cell cycle resumes following repair. These findings may have implications to the mechanisms by which cells sense the completion of repair.
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Affiliation(s)
- Michael Tsabar
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States
| | - Wade M Hicks
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States
| | - Olga Tsaponina
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, United States.
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22
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Lafon A, Taranum S, Pietrocola F, Dingli F, Loew D, Brahma S, Bartholomew B, Papamichos-Chronakis M. INO80 Chromatin Remodeler Facilitates Release of RNA Polymerase II from Chromatin for Ubiquitin-Mediated Proteasomal Degradation. Mol Cell 2015; 60:784-796. [PMID: 26656161 DOI: 10.1016/j.molcel.2015.10.028] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 08/17/2015] [Accepted: 10/14/2015] [Indexed: 12/13/2022]
Abstract
Stalling of RNA Polymerase II (RNAPII) on chromatin during transcriptional stress results in polyubiquitination and degradation of the largest subunit of RNAPII, Rpb1, by the ubiquitin proteasome system (UPS). Here, we report that the ATP-dependent chromatin remodeling complex INO80 is required for turnover of chromatin-bound RNAPII in yeast. INO80 interacts physically and functionally with Cdc48/p97/VCP, a component of UPS required for degradation of RNAPII. Cells lacking INO80 are defective in Rpb1 degradation and accumulate tightly bound ubiquitinated Rpb1 on chromatin. INO80 forms a ternary complex with RNAPII and Cdc48 and targets Rpb1 primed for degradation. The function of INO80 in RNAPII turnover is required for cell growth and survival during genotoxic stress. Our results identify INO80 as a bona fide component of the proteolytic pathway for RNAPII degradation and suggest that INO80 nucleosome remodeling activity promotes the dissociation of ubiquitinated Rpb1 from chromatin to protect the integrity of the genome.
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Affiliation(s)
- Anne Lafon
- Institut Curie, PSL Research University, CNRS, UMR3664, 26 rue d'Ulm, 75248 Paris, France
| | - Surayya Taranum
- Institut Curie, PSL Research University, CNRS, UMR3664, 26 rue d'Ulm, 75248 Paris, France
| | - Federico Pietrocola
- Institut Curie, PSL Research University, CNRS, UMR3664, 26 rue d'Ulm, 75248 Paris, France
| | - Florent Dingli
- Institut Curie, PSL Research University, Laboratory of Proteomics and Mass Spectrometry, 26 rue d'Ulm, 75248 Paris, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Laboratory of Proteomics and Mass Spectrometry, 26 rue d'Ulm, 75248 Paris, France
| | - Sandipan Brahma
- UT MD Anderson Cancer Center, Science Park, 1808 Park Road 1C, Smithville, TX 78957, USA
| | - Blaine Bartholomew
- UT MD Anderson Cancer Center, Science Park, 1808 Park Road 1C, Smithville, TX 78957, USA
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23
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Abstract
Homology-dependent exchange of genetic information between DNA molecules has a profound impact on the maintenance of genome integrity by facilitating error-free DNA repair, replication, and chromosome segregation during cell division as well as programmed cell developmental events. This chapter will focus on homologous mitotic recombination in budding yeast Saccharomyces cerevisiae. However, there is an important link between mitotic and meiotic recombination (covered in the forthcoming chapter by Hunter et al. 2015) and many of the functions are evolutionarily conserved. Here we will discuss several models that have been proposed to explain the mechanism of mitotic recombination, the genes and proteins involved in various pathways, the genetic and physical assays used to discover and study these genes, and the roles of many of these proteins inside the cell.
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24
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Structural analyses of the chromatin remodelling enzymes INO80-C and SWR-C. Nat Commun 2015; 6:7108. [PMID: 25964121 PMCID: PMC4431590 DOI: 10.1038/ncomms8108] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 04/01/2015] [Indexed: 01/11/2023] Open
Abstract
INO80-C and SWR-C are conserved members of a subfamily of ATP-dependent chromatin remodeling enzymes that function in transcription and genome-maintenance pathways. A crucial role for these enzymes is to control chromosomal distribution of the H2A.Z histone variant. Here we use electron microscopy (EM) and two-dimensional (2D) class averaging to demonstrate that these remodeling enzymes have similar overall architectures. Each enzyme is characterized by a dynamic ‘tail’ domain and a compact ‘head’ that contains Rvb1/Rvb2 subunits organized as hexameric rings. EM class averages and mass spectrometry support the existence of single heterohexameric rings in both SWR-C and INO80-C. EM studies define the position of the Arp8/Arp4/Act1 module within INO80-C, and we find that this module enhances nucleosome binding affinity but is largely dispensable for remodeling activities. In contrast, the Ies6/Arp5 module is essential for INO80-C remodeling, and furthermore this module controls conformational changes that may couple nucleosome binding to remodeling.
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25
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Kirkland JG, Peterson MR, Still CD, Brueggeman L, Dhillon N, Kamakaka RT. Heterochromatin formation via recruitment of DNA repair proteins. Mol Biol Cell 2015; 26:1395-410. [PMID: 25631822 PMCID: PMC4454184 DOI: 10.1091/mbc.e14-09-1413] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Double-strand-break repair proteins interact with and recruit Sir proteins to ectopic sites in the genome. Recruitment results in gene silencing, which depends on Sir proteins, as well as on histone H2A modification. Silencing also results in the localization of the locus to the nuclear periphery. Heterochromatin formation and nuclear organization are important in gene regulation and genome fidelity. Proteins involved in gene silencing localize to sites of damage and some DNA repair proteins localize to heterochromatin, but the biological importance of these correlations remains unclear. In this study, we examined the role of double-strand-break repair proteins in gene silencing and nuclear organization. We find that the ATM kinase Tel1 and the proteins Mre11 and Esc2 can silence a reporter gene dependent on the Sir, as well as on other repair proteins. Furthermore, these proteins aid in the localization of silenced domains to specific compartments in the nucleus. We identify two distinct mechanisms for repair protein–mediated silencing—via direct and indirect interactions with Sir proteins, as well as by tethering loci to the nuclear periphery. This study reveals previously unknown interactions between repair proteins and silencing proteins and suggests insights into the mechanism underlying genome integrity.
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Affiliation(s)
- Jacob G Kirkland
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Misty R Peterson
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Christopher D Still
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Leo Brueggeman
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Namrita Dhillon
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Rohinton T Kamakaka
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
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26
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Direct interactions promote eviction of the Sir3 heterochromatin protein by the SWI/SNF chromatin remodeling enzyme. Proc Natl Acad Sci U S A 2014; 111:17827-32. [PMID: 25453095 DOI: 10.1073/pnas.1420096111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterochromatin is a specialized chromatin structure that is central to eukaryotic transcriptional regulation and genome stability. Despite its globally repressive role, heterochromatin must also be dynamic, allowing for its repair and replication. In budding yeast, heterochromatin formation requires silent information regulators (Sirs) Sir2p, Sir3p, and Sir4p, and these Sir proteins create specialized chromatin structures at telomeres and silent mating-type loci. Previously, we found that the SWI/SNF chromatin remodeling enzyme can catalyze the ATP-dependent eviction of Sir3p from recombinant nucleosomal arrays, and this activity enhances early steps of recombinational repair in vitro. Here, we show that the ATPase subunit of SWI/SNF, Swi2p/Snf2p, interacts with the heterochromatin structural protein Sir3p. Two interaction surfaces are defined, including an interaction between the ATPase domain of Swi2p and the nucleosome binding, Bromo-Adjacent-Homology domain of Sir3p. A SWI/SNF complex harboring a Swi2p subunit that lacks this Sir3p interaction surface is unable to evict Sir3p from nucleosomes, even though its ATPase and remodeling activities are intact. In addition, we find that the interaction between Swi2p and Sir3p is key for SWI/SNF to promote resistance to replication stress in vivo and for establishment of heterochromatin at telomeres.
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27
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Jeggo PA, Downs JA. Roles of chromatin remodellers in DNA double strand break repair. Exp Cell Res 2014; 329:69-77. [PMID: 25278484 DOI: 10.1016/j.yexcr.2014.09.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 10/24/2022]
Abstract
Now that we have a good understanding of the DNA double strand break (DSB) repair mechanisms and DSB-induced damage signalling, attention is focusing on the changes to the chromatin environment needed for efficient DSB repair. Mutations in chromatin remodelling complexes have been identified in cancers, making it important to evaluate how they impact upon genomic stability. Our current understanding of the DSB repair pathways suggests that each one has distinct requirements for chromatin remodelling. Moreover, restricting the extent of chromatin modifications could be a significant factor regulating the decision of pathway usage. In this review, we evaluate the distinct DSB repair pathways for their potential need for chromatin remodelling and review the roles of ATP-driven chromatin remodellers in the pathways.
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Affiliation(s)
- Penny A Jeggo
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
| | - Jessica A Downs
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, UK.
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28
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Glover L, Horn D. Locus-specific control of DNA resection and suppression of subtelomeric VSG recombination by HAT3 in the African trypanosome. Nucleic Acids Res 2014; 42:12600-13. [PMID: 25300492 PMCID: PMC4227765 DOI: 10.1093/nar/gku900] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The African trypanosome, Trypanosoma brucei, is a parasitic protozoan that achieves antigenic variation through DNA-repair processes involving Variant Surface Glycoprotein (VSG) gene rearrangements at subtelomeres. Subtelomeric suppression of DNA repair operates in eukaryotes but little is known about these controls in trypanosomes. Here, we identify a trypanosome histone acetyltransferase (HAT3) and a deacetylase (SIR2rp1) required for efficient RAD51-dependent homologous recombination. HAT3 and SIR2rp1 were required for RAD51-focus assembly and disassembly, respectively, at a chromosome-internal locus and a synthetic defect indicated distinct contributions to DNA repair. Although HAT3 promoted chromosome-internal recombination, it suppressed subtelomeric VSG recombination, and these locus-specific effects were mediated through differential production of ssDNA by DNA resection; HAT3 promoted chromosome-internal resection but suppressed subtelomeric resection. Consistent with the resection defect, HAT3 was specifically required for the G2-checkpoint response at a chromosome-internal locus. HAT3 also promoted resection at a second chromosome-internal locus comprising tandem-duplicated genes. We conclude that HAT3 and SIR2rp1 can facilitate temporally distinct steps in DNA repair. HAT3 promotes ssDNA formation and recombination at chromosome-internal sites but has the opposite effect at a subtelomeric VSG. These locus-specific controls reveal compartmentalization of the T. brucei genome in terms of the DNA-damage response and suppression of antigenic variation by HAT3.
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Affiliation(s)
- Lucy Glover
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - David Horn
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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29
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Solution-state conformation and stoichiometry of yeast Sir3 heterochromatin fibres. Nat Commun 2014; 5:4751. [PMID: 25163529 PMCID: PMC4151189 DOI: 10.1038/ncomms5751] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/21/2014] [Indexed: 12/21/2022] Open
Abstract
Heterochromatin is a repressive chromatin compartment essential for maintaining genomic integrity. A hallmark of heterochromatin is the presence of specialized nonhistone proteins that alter chromatin structure to inhibit transcription and recombination. It is generally assumed that heterochromatin is highly condensed. However, surprisingly little is known about the structure of heterochromatin or its dynamics in solution. In budding yeast, formation of heterochromatin at telomeres and the HM silent mating type loci require the Sir3 protein. Here, we use a combination of sedimentation velocity, atomic force microscopy, and nucleosomal array capture to characterize the stoichiometry and conformation of Sir3 nucleosomal arrays. The results indicate that Sir3 interacts with nucleosomal arrays with a stoichiometry of two Sir3 monomers per nucleosome. We also find that Sir3 fibers are less compact than canonical – magnesium-induced 30 nm fibers. We suggest that heterochromatin proteins promote silencing by “coating” nucleosomal arrays, stabilizing interactions between nucleosomal histones and DNA.
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30
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Renkawitz J, Lademann CA, Jentsch S. Mechanisms and principles of homology search during recombination. Nat Rev Mol Cell Biol 2014; 15:369-83. [PMID: 24824069 DOI: 10.1038/nrm3805] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homologous recombination is crucial for genome stability and for genetic exchange. Although our knowledge of the principle steps in recombination and its machinery is well advanced, homology search, the critical step of exploring the genome for homologous sequences to enable recombination, has remained mostly enigmatic. However, recent methodological advances have provided considerable new insights into this fundamental step in recombination that can be integrated into a mechanistic model. These advances emphasize the importance of genomic proximity and nuclear organization for homology search and the critical role of homology search mediators in this process. They also aid our understanding of how homology search might lead to unwanted and potentially disease-promoting recombination events.
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Affiliation(s)
- Jörg Renkawitz
- 1] Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. [2] Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria. [3]
| | - Claudio A Lademann
- 1] Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. [2]
| | - Stefan Jentsch
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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31
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Machida S, Takaku M, Ikura M, Sun J, Suzuki H, Kobayashi W, Kinomura A, Osakabe A, Tachiwana H, Horikoshi Y, Fukuto A, Matsuda R, Ura K, Tashiro S, Ikura T, Kurumizaka H. Nap1 stimulates homologous recombination by RAD51 and RAD54 in higher-ordered chromatin containing histone H1. Sci Rep 2014; 4:4863. [PMID: 24798879 PMCID: PMC4010968 DOI: 10.1038/srep04863] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 04/15/2014] [Indexed: 12/20/2022] Open
Abstract
Homologous recombination plays essential roles in mitotic DNA double strand break (DSB) repair and meiotic genetic recombination. In eukaryotes, RAD51 promotes the central homologous-pairing step during homologous recombination, but is not sufficient to overcome the reaction barrier imposed by nucleosomes. RAD54, a member of the ATP-dependent nucleosome remodeling factor family, is required to promote the RAD51-mediated homologous pairing in nucleosomal DNA. In higher eukaryotes, most nucleosomes form higher-ordered chromatin containing the linker histone H1. However, the mechanism by which RAD51/RAD54-mediated homologous pairing occurs in higher-ordered chromatin has not been elucidated. In this study, we found that a histone chaperone, Nap1, accumulates on DSB sites in human cells, and DSB repair is substantially decreased in Nap1-knockdown cells. We determined that Nap1 binds to RAD54, enhances the RAD54-mediated nucleosome remodeling by evicting histone H1, and eventually stimulates the RAD51-mediated homologous pairing in higher-ordered chromatin containing histone H1.
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Affiliation(s)
- Shinichi Machida
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- These authors contributed equally to this work
| | - Motoki Takaku
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
- These authors contributed equally to this work
| | - Masae Ikura
- Department of Mutagenesis, Division of Chromatin Regulatory Network, Radiation Biology Center, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Jiying Sun
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Hidekazu Suzuki
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Wataru Kobayashi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Aiko Kinomura
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Akihisa Osakabe
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hiroaki Tachiwana
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Yasunori Horikoshi
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Atsuhiko Fukuto
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Ryo Matsuda
- Department of Mutagenesis, Division of Chromatin Regulatory Network, Radiation Biology Center, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kiyoe Ura
- Division of Gene Therapy Science, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Satoshi Tashiro
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Tsuyoshi Ikura
- Department of Mutagenesis, Division of Chromatin Regulatory Network, Radiation Biology Center, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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32
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Mechanisms by which SMARCB1 loss drives rhabdoid tumor growth. Cancer Genet 2014; 207:365-72. [PMID: 24853101 DOI: 10.1016/j.cancergen.2014.04.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/01/2014] [Accepted: 04/02/2014] [Indexed: 02/02/2023]
Abstract
SMARCB1 (INI1/SNF5/BAF47), a core subunit of the SWI/SNF (BAF) chromatin-remodeling complex, is inactivated in the large majority of rhabdoid tumors, and germline heterozygous SMARCB1 mutations form the basis for rhabdoid predisposition syndrome. Mouse models validated Smarcb1 as a bona fide tumor suppressor, as Smarcb1 inactivation in mice results in 100% of the animals rapidly developing cancer. SMARCB1 was the first subunit of the SWI/SNF complex found mutated in cancer. More recently, at least seven other genes encoding SWI/SNF subunits have been identified as recurrently mutated in cancer. Collectively, 20% of all human cancers contain a SWI/SNF mutation. Consequently, investigation of the mechanisms by which SMARCB1 mutation causes cancer has relevance not only for rhabdoid tumors, but also potentially for the wide variety of SWI/SNF mutant cancers. Here we discuss normal functions of SMARCB1 and the SWI/SNF complex as well as mechanistic and potentially therapeutic insights that have emerged.
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33
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Duan MR, Smerdon MJ. Histone H3 lysine 14 (H3K14) acetylation facilitates DNA repair in a positioned nucleosome by stabilizing the binding of the chromatin Remodeler RSC (Remodels Structure of Chromatin). J Biol Chem 2014; 289:8353-63. [PMID: 24515106 DOI: 10.1074/jbc.m113.540732] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Histone H3 acetylation is induced by UV damage in yeast and may play an important role in regulating the repair of UV photolesions in nucleosome-loaded genomic loci. However, it remains elusive how H3 acetylation facilitates repair. We generated a strongly positioned nucleosome containing homogeneously acetylated H3 at Lys-14 (H3K14ac) and investigated possible mechanisms by which H3K14 acetylation modulates repair. We show that H3K14ac does not alter nucleosome unfolding dynamics or enhance the repair of UV-induced cyclobutane pyrimidine dimers by UV photolyase. Importantly, however, nucleosomes with H3K14ac have a higher affinity for purified chromatin remodeling complex RSC (Remodels the Structure of Chromatin) and show greater cyclobutane pyrimidine dimer repair compared with unacetylated nucleosomes. Our study indicates that, by anchoring RSC, H3K14 acetylation plays an important role in the unfolding of strongly positioned nucleosomes during repair of UV damage.
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Affiliation(s)
- Ming-Rui Duan
- From Biochemistry and Biophysics, School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-7520
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34
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Kwon SJ, Park JH, Park EJ, Lee SA, Lee HS, Kang SW, Kwon J. ATM-mediated phosphorylation of the chromatin remodeling enzyme BRG1 modulates DNA double-strand break repair. Oncogene 2014; 34:303-13. [PMID: 24413084 DOI: 10.1038/onc.2013.556] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 12/25/2022]
Abstract
ATP-dependent chromatin remodeling complexes such as SWI/SNF (SWItch/Sucrose NonFermentable) have been implicated in DNA double-strand break (DSB) repair and damage responses. However, the regulatory mechanisms that control the function of chromatin remodelers in DNA damage response are largely unknown. Here, we show that ataxia telangiectasia mutated (ATM) mediates the phosphorylation of BRG1, the catalytic ATPase of the SWI/SNF complex that contributes to DSB repair by binding γ-H2AX-containing nucleosomes via interaction with acetylated histone H3 and stimulating γ-H2AX formation, at Ser-721 in response to DNA damage. ATM-mediated phosphorylation of BRG1 occurs rapidly and transiently after DNA damage. Phosphorylated BRG1 binds γ-H2AX-containing nucleosomes to form the repair foci. The Ser-721 phosphorylation of BRG1 is critical for binding γ-H2AX-containing nucleosomes and stimulating γ-H2AX formation and DSB repair. BRG1 binds to acetylated H3 peptides much better after phosphorylation at Ser-721 by DNA damage. However, the phosphorylation of Ser-721 does not significantly affect the ATPase and transcriptional activities of BRG1. These results, establishing BRG1 as a novel and functional ATM substrate, suggest that the ATM-mediated phosphorylation of BRG1 facilitates DSB repair by stimulating the association of this remodeler with γ-H2AX nucleosomes via enhancing the affinity to acetylated H3. Our work also suggests that the mechanism of BRG1 stimulation of DNA repair is independent of the remodeler's enzymatic or transcriptional activities.
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Affiliation(s)
- S-J Kwon
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - J-H Park
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - E-J Park
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - S-A Lee
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - H-S Lee
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - S W Kang
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
| | - J Kwon
- Department of Life Science, College of Natural Sciences, The Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Republic of Korea
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35
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Peterson CL, Almouzni G. Nucleosome dynamics as modular systems that integrate DNA damage and repair. Cold Spring Harb Perspect Biol 2013; 5:5/9/a012658. [PMID: 24003210 DOI: 10.1101/cshperspect.a012658] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
By some estimates, a eukaryotic cell must repair up to 10,000 DNA lesions per cell cycle to counteract endogenous sources of DNA damage. Exposure to environmental toxins, UV sources, or other radiations only increases this enormous number. Failure to repair such lesions can lead to a deleterious mutation rate, genomic instability, or cell death. The timely and efficient repair of eukaryotic DNA damage is further complicated by the realization that DNA lesions must be detected and repaired in the context of chromatin with its complex organization within the nucleus. Numerous studies have shown that chromatin packaging can inhibit nearly all repair pathways, and recent work has defined specific mechanisms that facilitate DNA repair within the chromatin context. In this review, we provide a broad overview of chromatin regulatory mechanisms, mainly at the nucleosomal level, and then focus on recent work that elucidates the role of chromatin structure in regulating the timely and efficient repair of DNA double-strand breaks (DSBs).
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Affiliation(s)
- Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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36
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Oppikofer M, Kueng S, Gasser SM. SIR–nucleosome interactions: Structure–function relationships in yeast silent chromatin. Gene 2013; 527:10-25. [DOI: 10.1016/j.gene.2013.05.088] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 05/27/2013] [Accepted: 05/30/2013] [Indexed: 01/09/2023]
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37
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Johnson A, Wu R, Peetz M, Gygi SP, Moazed D. Heterochromatic gene silencing by activator interference and a transcription elongation barrier. J Biol Chem 2013; 288:28771-82. [PMID: 23940036 PMCID: PMC3789973 DOI: 10.1074/jbc.m113.460071] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Heterochromatin silences transcription, contributing to development, differentiation, and genome stability in eukaryotic organisms. Budding yeast heterochromatic silencing is strictly dependent on the silent information regulator (SIR) complex composed of the Sir2 histone deacetylase and the chromatin-interacting proteins Sir3 and Sir4. We use reconstituted SIR heterochromatin to characterize the steps in transcription that are disrupted to achieve silencing. Transcriptional activator binding is permitted before and after heterochromatin assembly. A comprehensive proteomic approach identified heterochromatin-mediated disruption of activator interactions with coactivator complexes. We also find that if RNA polymerase II (Pol II) is allowed to initiate transcription, the SIR complex blocks elongation on chromatin while maintaining Pol II in a halted conformation. This Pol II elongation barrier functions for even one nucleosome, is more effective when assembled with multiple nucleosomes, and is sensitive to a histone mutation that is known to disrupt silencing. This dual mechanism of silencing suggests a conserved principle of heterochromatin in assembling a specific structure that targets multiple steps to achieve repression.
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38
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Gospodinov A, Herceg Z. Chromatin structure in double strand break repair. DNA Repair (Amst) 2013; 12:800-10. [PMID: 23919923 DOI: 10.1016/j.dnarep.2013.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 12/16/2022]
Abstract
Cells are under constant assault by endogenous and environmental DNA damaging agents. DNA double strand breaks (DSBs) sever entire chromosomes and pose a major threat to genome integrity as a result of chromosomal fragment loss or chromosomal rearrangements. Exogenous factors such as ionizing radiation, crosslinking agents, and topoisomerase poisons, contribute to break formation. DSBs are associated with oxidative metabolism, form during the normal S phase, when replication forks collapse and are generated during physiological processes such as V(D)J recombination, yeast mating type switching and meiosis. It is estimated that in mammalian cells ∼10 DSBs per cell are formed daily. If left unrepaired DSBs can lead to cell death or deregulated growth, and cancer development. Cellular response to DSB damage includes mechanisms to halt the progression of the cell cycle and to restore the structure of the broken chromosome. Changes in chromatin adjacent to DNA break sites are instrumental to the DNA damage response (DDR) with two apparent ends: to control compaction and to bind repair and signaling molecules to the lesion. Here, we review the key findings related to each of these functions and examine their cross-talk.
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Affiliation(s)
- Anastas Gospodinov
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. 21, 1113 Sofia, Bulgaria.
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39
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Grunstein M, Gasser SM. Epigenetics in Saccharomyces cerevisiae. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a017491. [PMID: 23818500 DOI: 10.1101/cshperspect.a017491] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Saccharomyces cerevisiae provides a well-studied model system for heritable silent chromatin, in which a nonhistone protein complex--the SIR complex--represses genes by spreading in a sequence-independent manner, much like heterochromatin in higher eukaryotes. The ability to study mutations in histones and to screen genome-wide for mutations that impair silencing has yielded an unparalleled depth of detail about this system. Recent advances in the biochemistry and structural biology of the SIR-chromatin complex bring us much closer to a molecular understanding of how Sir3 selectively recognizes the deacetylated histone H4 tail and demethylated histone H3 core. The existence of appropriate mutants has also shown how components of the silencing machinery affect physiological processes beyond transcriptional repression.
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Affiliation(s)
- Michael Grunstein
- University of California, Los Angeles, Los Angeles, California 90095, USA
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40
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Watanabe S, Radman-Livaja M, Rando OJ, Peterson CL. A histone acetylation switch regulates H2A.Z deposition by the SWR-C remodeling enzyme. Science 2013; 340:195-9. [PMID: 23580526 DOI: 10.1126/science.1229758] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The histone variant H2A.Z plays key roles in gene expression, DNA repair, and centromere function. H2A.Z deposition is controlled by SWR-C chromatin remodeling enzymes that catalyze the nucleosomal exchange of canonical H2A with H2A.Z. Here we report that acetylation of histone H3 on lysine 56 (H3-K56Ac) alters the substrate specificity of SWR-C, leading to promiscuous dimer exchange in which either H2A.Z or H2A can be exchanged from nucleosomes. This result was confirmed in vivo, where genome-wide analysis demonstrated widespread decreases in H2A.Z levels in yeast mutants with hyperacetylated H3K56. Our work also suggests that a conserved SWR-C subunit may function as a "lock" that prevents removal of H2A.Z from nucleosomes. Our study identifies a histone modification that regulates a chromatin remodeling reaction and provides insights into how histone variants and nucleosome turnover can be controlled by chromatin regulators.
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Affiliation(s)
- Shinya Watanabe
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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41
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Tsabar M, Haber JE. Chromatin modifications and chromatin remodeling during DNA repair in budding yeast. Curr Opin Genet Dev 2013; 23:166-73. [PMID: 23602331 DOI: 10.1016/j.gde.2012.11.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/19/2012] [Indexed: 02/03/2023]
Abstract
Double-strand breaks (DSBs) pose a serious threat to genome integrity. Eukaryotes from yeast to humans respond to DSB damage by activating a complex DNA damage response that includes imposing a block to cell cycle progression and the repair of the DSB by one of several pathways. Many of these processes are accompanied by alterations in chromosome and chromatin structure. In this review we focus on the checkpoint responses and DNA repair in the well-studied model organism, the budding yeast Saccharomyces cerevisiae.
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Affiliation(s)
- Michael Tsabar
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Waltham, MA 02454-9110, United States
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42
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Abstract
The maintenance of genome integrity is essential for organism survival and for the inheritance of traits to offspring. Genomic instability is caused by DNA damage, aberrant DNA replication or uncoordinated cell division, which can lead to chromosomal aberrations and gene mutations. Recently, chromatin regulators that shape the epigenetic landscape have emerged as potential gatekeepers and signalling coordinators for the maintenance of genome integrity. Here, we review chromatin functions during the two major pathways that control genome integrity: namely, repair of DNA damage and DNA replication. We also discuss recent evidence that suggests a novel role for chromatin-remodelling factors in chromosome segregation and in the prevention of aneuploidy.
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43
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Seeber A, Hauer M, Gasser SM. Nucleosome remodelers in double-strand break repair. Curr Opin Genet Dev 2013; 23:174-84. [PMID: 23352131 DOI: 10.1016/j.gde.2012.12.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 12/03/2012] [Accepted: 12/20/2012] [Indexed: 11/25/2022]
Abstract
ATP-dependent nucleosome remodelers use ATP hydrolysis to shift, evict and exchange histone dimers or octamers and have well-established roles in transcription. Earlier work has suggested a role for nucleosome remodelers such as INO80 in double-strand break (DSB) repair. This review will begin with an update on recent studies that explore how remodelers are recruited to DSBs. We then examine their impact on various steps of repair, focusing on resection and the formation of the Rad51-ssDNA nucleofilament. Finally, we will explore new studies that implicate remodelers in the physical movement of chromatin in response to damage.
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Affiliation(s)
- Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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44
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Soria G, Polo SE, Almouzni G. Prime, repair, restore: the active role of chromatin in the DNA damage response. Mol Cell 2012; 46:722-34. [PMID: 22749398 DOI: 10.1016/j.molcel.2012.06.002] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/21/2012] [Accepted: 06/08/2012] [Indexed: 11/24/2022]
Abstract
The view of DNA packaging into chromatin as a mere obstacle to DNA repair is evolving. In this review, we focus on histone variants and heterochromatin proteins as chromatin components involved in distinct levels of chromatin organization to integrate them as real players in the DNA damage response (DDR). Based on recent data, we highlight how some of these chromatin components play active roles in the DDR and contribute to the fine-tuning of damage signaling, DNA and chromatin repair. To take into account this integrated view, we revisit the existing access-repair-restore model and propose a new working model involving priming chromatin for repair and restoration as a concerted process. We discuss how this impacts on both genomic and epigenomic stability and plasticity.
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Affiliation(s)
- Gaston Soria
- Laboratory of Chromatin Dynamics, Institut Curie Section Recherche, 75248 Paris Cedex 5, France
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45
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Gospodinov A, Herceg Z. Shaping chromatin for repair. Mutat Res 2012; 752:45-60. [PMID: 23085398 DOI: 10.1016/j.mrrev.2012.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 12/19/2022]
Abstract
To counteract the adverse effects of various DNA lesions, cells have evolved an array of diverse repair pathways to restore DNA structure and to coordinate repair with cell cycle regulation. Chromatin changes are an integral part of the DNA damage response, particularly with regard to the types of repair that involve assembly of large multiprotein complexes such as those involved in double strand break (DSB) repair and nucleotide excision repair (NER). A number of phosphorylation, acetylation, methylation, ubiquitylation and chromatin remodeling events modulate chromatin structure at the lesion site. These changes demarcate chromatin neighboring the lesion, afford accessibility and binding surfaces to repair factors and provide on-the-spot means to coordinate repair and damage signaling. Thus, the hierarchical assembly of repair factors at a double strand break is mostly due to their regulated interactions with posttranslational modifications of histones. A large number of chromatin remodelers are required at different stages of DSB repair and NER. Remodelers physically interact with proteins involved in repair processes, suggesting that chromatin remodeling is a requisite for repair factors to access the damaged site. Together, recent findings define the roles of histone post-translational modifications and chromatin remodeling in the DNA damage response and underscore possible differences in the requirements for these events in relation to the chromatin context.
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Affiliation(s)
- Anastas Gospodinov
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. 21, 1113 Sofia, Bulgaria
| | - Zdenko Herceg
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 Cours Albert Thomas, 69008, Lyon, France.
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46
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The emerging roles of ATP-dependent chromatin remodeling enzymes in nucleotide excision repair. Int J Mol Sci 2012; 13:11954-11973. [PMID: 23109894 PMCID: PMC3472786 DOI: 10.3390/ijms130911954] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 08/30/2012] [Accepted: 08/31/2012] [Indexed: 12/14/2022] Open
Abstract
DNA repair in eukaryotic cells takes place in the context of chromatin, where DNA, including damaged DNA, is tightly packed into nucleosomes and higher order chromatin structures. Chromatin intrinsically restricts accessibility of DNA repair proteins to the damaged DNA and impacts upon the overall rate of DNA repair. Chromatin is highly responsive to DNA damage and undergoes specific remodeling to facilitate DNA repair. How damaged DNA is accessed, repaired and restored to the original chromatin state, and how chromatin remodeling coordinates these processes in vivo, remains largely unknown. ATP-dependent chromatin remodelers (ACRs) are the master regulators of chromatin structure and dynamics. Conserved from yeast to humans, ACRs utilize the energy of ATP to reorganize packing of chromatin and control DNA accessibility by sliding, ejecting or restructuring nucleosomes. Several studies have demonstrated that ATP-dependent remodeling activity of ACRs plays important roles in coordination of spatio-temporal steps of different DNA repair pathways in chromatin. This review focuses on the role of ACRs in regulation of various aspects of nucleotide excision repair (NER) in the context of chromatin. We discuss current understanding of ATP-dependent chromatin remodeling by various subfamilies of remodelers and regulation of the NER pathway in vivo.
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47
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Sinha M, Peterson CL. Chromatin dynamics during repair of chromosomal DNA double-strand breaks. Epigenomics 2012; 1:371-85. [PMID: 20495614 DOI: 10.2217/epi.09.22] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The integrity of a eukaryotic genome is often challenged by DNA double-strand breaks (DSBs). Even a single, unrepaired DSB can be a lethal event, or such unrepaired damage can result in chromosomal instability and loss of genetic information. Furthermore, defects in the pathways that respond to and repair DSBs can lead to the onset of several human pathologic disorders with pleiotropic clinical features, including age-related diseases and cancer. For decades, studies have focused on elucidating the enzymatic mechanisms involved in recognizing, signaling and repairing DSBs within eukaryotic cells. The majority of biochemical and genetic studies have used simple, DNA substrates, whereas only recently efforts have been geared towards understanding how the repair machinery deals with DSBs within chromatin fibers, the nucleoprotein complex that packages DNA within the eukaryotic nucleus. The aim of this review is to discuss our recent understanding of the relationship between chromatin structure and the repair of DSBs by homologous recombination. In particular, we discuss recent studies implicating specialized roles for several, distinct ATP-dependent chromatin remodeling enzymes in facilitating multiple steps within the homologous recombination process.
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Affiliation(s)
- Manisha Sinha
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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48
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New regulators of biofilm development in Candida glabrata. Res Microbiol 2012; 163:297-307. [PMID: 22426249 DOI: 10.1016/j.resmic.2012.02.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 02/15/2012] [Indexed: 12/31/2022]
Abstract
Biofilm formation plays an important role in fungal pathogenesis. In this work, we used a genetic screen in order to identify and characterize genes involved in the formation of biofilms by the opportunistic fungal pathogen Candida glabrata. We identified the Cst6p transcription factor as a negative regulator of the EPA6 gene that encodes an adhesin central to C. glabrata biofilm formation. Analysis of single and double mutant strains showed that Cst6p acts in a pathway independent of the Yak1/Sir4 pathway also known to regulate expression of EPA6 and consequently biofilm formation. In contrast, we showed that the chromatin remodelling Swi/Snf complex positively regulates biofilm formation in C. glabrata. RT-qPCR experiments demonstrated that EPA6 expression, and thus biofilm formation, depends on the integrity of the Sir complex. Finally, we showed that Swi/Snf-dependent regulation of biofilm formation is adhesin-specific.
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49
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Kim Y, Fedoriw AM, Magnuson T. An essential role for a mammalian SWI/SNF chromatin-remodeling complex during male meiosis. Development 2012; 139:1133-40. [PMID: 22318225 DOI: 10.1242/dev.073478] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Germ cell development and gametogenesis require genome-wide transitions in epigenetic modifications and chromatin structure. These changes include covalent modifications to the DNA and histones as well as remodeling activities. Here, we explore the role of the mammalian SWI/SNF chromatin-remodeling complex during spermatogenesis using a conditional allele of the ATPase subunit, brahma-related gene 1 (Brg1, or Smarca4). Not only do BRG1 levels peak during the early stages of meiosis, genetic ablation of Brg1 in murine embryonic gonocytes results in arrest during prophase of meiosis I. Coincident with the timing of meiotic arrest, mutant spermatocytes accumulate unrepaired DNA and fail to complete synapsis. Furthermore, mutant spermatocytes show global alterations to histone modifications and chromatin structure indicative of a more heterochromatic genome. Together, these data demonstrate a requirement for BRG1 activity in spermatogenesis, and suggest a role for the mammalian SWI/SNF complex in programmed recombination and repair events that take place during meiosis.
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Affiliation(s)
- Yuna Kim
- Department of Genetics, Carolina Center for Genome Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, NC 27599-7264, USA
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50
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Lans H, Marteijn JA, Vermeulen W. ATP-dependent chromatin remodeling in the DNA-damage response. Epigenetics Chromatin 2012; 5:4. [PMID: 22289628 PMCID: PMC3275488 DOI: 10.1186/1756-8935-5-4] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 01/30/2012] [Indexed: 12/31/2022] Open
Abstract
The integrity of DNA is continuously challenged by metabolism-derived and environmental genotoxic agents that cause a variety of DNA lesions, including base alterations and breaks. DNA damage interferes with vital processes such as transcription and replication, and if not repaired properly, can ultimately lead to premature aging and cancer. Multiple DNA pathways signaling for DNA repair and DNA damage collectively safeguard the integrity of DNA. Chromatin plays a pivotal role in regulating DNA-associated processes, and is itself subject to regulation by the DNA-damage response. Chromatin influences access to DNA, and often serves as a docking or signaling site for repair and signaling proteins. Its structure can be adapted by post-translational histone modifications and nucleosome remodeling, catalyzed by the activity of ATP-dependent chromatin-remodeling complexes. In recent years, accumulating evidence has suggested that ATP-dependent chromatin-remodeling complexes play important, although poorly characterized, roles in facilitating the effectiveness of the DNA-damage response. In this review, we summarize the current knowledge on the involvement of ATP-dependent chromatin remodeling in three major DNA repair pathways: nucleotide excision repair, homologous recombination, and non-homologous end-joining. This shows that a surprisingly large number of different remodeling complexes display pleiotropic functions during different stages of the DNA-damage response. Moreover, several complexes seem to have multiple functions, and are implicated in various mechanistically distinct repair pathways.
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Affiliation(s)
- Hannes Lans
- Department of Genetics, Medical Genetics Center, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
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