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Oravcová M, Nie M, Zilio N, Maeda S, Jami-Alahmadi Y, Lazzerini-Denchi E, Wohlschlegel JA, Ulrich HD, Otomo T, Boddy MN. The Nse5/6-like SIMC1-SLF2 complex localizes SMC5/6 to viral replication centers. eLife 2022; 11:e79676. [PMID: 36373674 PMCID: PMC9708086 DOI: 10.7554/elife.79676] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
The human SMC5/6 complex is a conserved guardian of genome stability and an emerging component of antiviral responses. These disparate functions likely require distinct mechanisms of SMC5/6 regulation. In yeast, Smc5/6 is regulated by its Nse5/6 subunits, but such regulatory subunits for human SMC5/6 are poorly defined. Here, we identify a novel SMC5/6 subunit called SIMC1 that contains SUMO interacting motifs (SIMs) and an Nse5-like domain. We isolated SIMC1 from the proteomic environment of SMC5/6 within polyomavirus large T antigen (LT)-induced subnuclear compartments. SIMC1 uses its SIMs and Nse5-like domain to localize SMC5/6 to polyomavirus replication centers (PyVRCs) at SUMO-rich PML nuclear bodies. SIMC1's Nse5-like domain binds to the putative Nse6 orthologue SLF2 to form an anti-parallel helical dimer resembling the yeast Nse5/6 structure. SIMC1-SLF2 structure-based mutagenesis defines a conserved surface region containing the N-terminus of SIMC1's helical domain that regulates SMC5/6 localization to PyVRCs. Furthermore, SLF1, which recruits SMC5/6 to DNA lesions via its BRCT and ARD motifs, binds SLF2 analogously to SIMC1 and forms a separate Nse5/6-like complex. Thus, two Nse5/6-like complexes with distinct recruitment domains control human SMC5/6 localization.
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Affiliation(s)
- Martina Oravcová
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
| | - Minghua Nie
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
| | | | - Shintaro Maeda
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States
| | | | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States
| | | | - Takanori Otomo
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
- San Diego Biomedical Research InstituteSan DiegoUnited States
| | - Michael N Boddy
- Department of Molecular Medicine, The Scripps Research InstituteLa JollaUnited States
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2
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Tu J, Yu S, Li J, Ren M, Zhang Y, Luo J, Sun K, Lv Y, Han Y, Huang Y, Ren X, Jiang T, Tang Z, Williams MTS, Lu Q, Liu M. Dhx38 is required for the maintenance and differentiation of erythro-myeloid progenitors and hematopoietic stem cells by alternative splicing. Development 2022; 149:276218. [DOI: 10.1242/dev.200450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 07/21/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Mutations that occur in RNA-splicing machinery may contribute to hematopoiesis-related diseases. How splicing factor mutations perturb hematopoiesis, especially in the differentiation of erythro-myeloid progenitors (EMPs), remains elusive. Dhx38 is a pre-mRNA splicing-related DEAH box RNA helicase, for which the physiological functions and splicing mechanisms during hematopoiesis currently remain unclear. Here, we report that Dhx38 exerts a broad effect on definitive EMPs as well as the differentiation and maintenance of hematopoietic stem and progenitor cells (HSPCs). In dhx38 knockout zebrafish, EMPs and HSPCs were found to be arrested in mitotic prometaphase, accompanied by a ‘grape’ karyotype, owing to the defects in chromosome alignment. Abnormal alternatively spliced genes related to chromosome segregation, the microtubule cytoskeleton, cell cycle kinases and DNA damage were present in the dhx38 mutants. Subsequently, EMPs and HSPCs in dhx38 mutants underwent P53-dependent apoptosis. This study provides novel insights into alternative splicing regulated by Dhx38, a process that plays a crucial role in the proliferation and differentiation of fetal EMPs and HSPCs.
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Affiliation(s)
- Jiayi Tu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Shanshan Yu
- Institute of Visual Neuroscience and Stem Cell Engineering, College of Life Sciences and Health, Wuhan University of Science and Technology 2 , Wuhan, Hubei 430065 , P.R. China
| | - Jingzhen Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Mengmeng Ren
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Yangjun Zhang
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology 3 , Wuhan 430030 , P.R. China
| | - Jiong Luo
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Kui Sun
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Yuexia Lv
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Yunqiao Han
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Xiang Ren
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Tao Jiang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Mark Thomas Shaw Williams
- Charles Oakley Laboratories 4 , Department of Biological and Biomedical Sciences , , Glasgow G4 0BA , UK
- Glasgow Caledonian University 4 , Department of Biological and Biomedical Sciences , , Glasgow G4 0BA , UK
| | - Qunwei Lu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology 1 , Wuhan 430074 , P.R. China
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3
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Chen H, He C, Wang C, Wang X, Ruan F, Yan J, Yin P, Wang Y, Yan S. RAD51 supports DMC1 by inhibiting the SMC5/6 complex during meiosis. THE PLANT CELL 2021; 33:2869-2882. [PMID: 34009315 PMCID: PMC8408460 DOI: 10.1093/plcell/koab136] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/12/2021] [Indexed: 05/21/2023]
Abstract
Meiosis is a fundamental process for sexual reproduction in most eukaryotes and the evolutionarily conserved recombinases RADiation sensitive51 (RAD51) and Disrupted Meiotic cDNA1 (DMC1) are essential for meiosis and thus fertility. The mitotic function of RAD51 is clear, but the meiotic function of RAD51 remains largely unknown. Here we show that RAD51 functions as an interacting protein to restrain the Structural Maintenance of Chromosomes5/6 (SMC5/6) complex from inhibiting DMC1. We unexpectedly found that loss of the SMC5/6 partially suppresses the rad51 knockout mutant in terms of sterility, pollen inviability, and meiotic chromosome fragmentation in a DMC1-dependent manner in Arabidopsis thaliana. Biochemical and cytological studies revealed that the DMC1 localization in meiotic chromosomes is inhibited by the SMC5/6 complex, which is attenuated by RAD51 through physical interactions. This study not only identified the long-sought-after function of RAD51 in meiosis but also discovered the inhibition of SMC5/6 on DMC1 as a control mechanism during meiotic recombination.
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Affiliation(s)
- Hanchen Chen
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Chengpeng He
- State Key Laboratory of Genetic Engineering and Ministry of Education, Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Chongyang Wang
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Xuanpeng Wang
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Fengyin Ruan
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Junjie Yan
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Ping Yin
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
| | - Yingxiang Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education, Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China
- Author for correspondence: (S.Y.), (Y.W.)
| | - Shunping Yan
- College of Life Science and Technology, Center of Integrative Biology, Interdisciplinary Science Research Institute, Huazhong Agricultural University, Wuhan 430070, China
- Author for correspondence: (S.Y.), (Y.W.)
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4
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Smc5/6, an atypical SMC complex with two RING-type subunits. Biochem Soc Trans 2021; 48:2159-2171. [PMID: 32964921 DOI: 10.1042/bst20200389] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 01/06/2023]
Abstract
The Smc5/6 complex plays essential roles in chromosome segregation and repair, by promoting disjunction of sister chromatids. The core of the complex is constituted by an heterodimer of Structural Maintenance of Chromosomes (SMC) proteins that use ATP hydrolysis to dynamically associate with and organize chromosomes. In addition, the Smc5/6 complex contains six non-SMC subunits. Remarkably, and differently to other SMC complexes, the Nse1 and Nse2 subunits contain RING-type domains typically found in E3 ligases, pointing to the capacity to regulate other proteins and complexes through ubiquitin-like modifiers. Nse2 codes for a C-terminal SP-RING domain with SUMO ligase activity, assisting Smc5/6 functions in chromosome segregation through sumoylation of several chromosome-associated proteins. Nse1 codes for a C-terminal NH-RING domain and, although it has been proposed to have ubiquitin ligase activity, no Smc5/6-dependent ubiquitylation target has been described to date. Here, we review the function of the two RING domains of the Smc5/6 complex in the broader context of SMC complexes as global chromosome organizers of the genome.
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5
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Abstract
During meiosis, homologous chromosomes of a diploid cell are replicated and, without a second replication, are segregated during two nuclear divisions to produce four haploid cells (including discarded polar bodies in females of many species). Proper segregation of chromosomes at the first division requires in most species that homologous chromosomes be physically connected. Tension generated by connected chromosomes moving to opposite sides of the cell signals proper segregation. In the absence of the required connections, called crossovers, chromosomes often segregate randomly and produce aneuploid gametes and, thus, dead or disabled progeny. To be effective, crossovers must be properly distributed along chromosomes. Crossovers within or too near the centromere interfere with proper segregation; crossovers too near each other can ablate the required tension; and crossovers too concentrated in only one or a few regions would not re-assort most genetic characters important for evolution. Here, we discuss current knowledge of how the optimal distribution of crossovers is achieved in the fission yeast Schizosaccharomyces pombe, with reference to other well-studied species for comparison and illustration of the diversity of biology.
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Affiliation(s)
- Mridula Nambiar
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA, 98112, United States
| | - Yu-Chien Chuang
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA, 98112, United States
| | - Gerald R Smith
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA, 98112, United States.
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6
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Abstract
Smc5 and Smc6, together with the kleisin Nse4, form the heart of the enigmatic and poorly understood Smc5/6 complex, which is frequently viewed as a cousin of cohesin and condensin with functions in DNA repair. As novel functions for cohesin and condensin complexes in the organization of long-range chromatin architecture have recently emerged, new unsuspected roles for Smc5/6 have also surfaced. Here, I aim to provide a comprehensive overview of our current knowledge of the Smc5/6 complex, including its long-established function in genome stability, its multiple roles in DNA repair, and its recently discovered connection to the transcription inhibition of hepatitis B virus genomes. In addition, I summarize new research that is beginning to tease out the molecular details of Smc5/6 structure and function, knowledge that will illuminate the nuclear activities of Smc5/6 in the stability and dynamics of eukaryotic genomes.
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Affiliation(s)
- Luis Aragón
- Cell Cycle Group, MRC London Institute of Medical Sciences, Hammersmith Hospital Campus, London W12 0NN, United Kingdom;
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7
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Hesse S, Zelkowski M, Mikhailova EI, Keijzer CJ, Houben A, Schubert V. Ultrastructure and Dynamics of Synaptonemal Complex Components During Meiotic Pairing and Synapsis of Standard (A) and Accessory (B) Rye Chromosomes. FRONTIERS IN PLANT SCIENCE 2019; 10:773. [PMID: 31281324 PMCID: PMC6596450 DOI: 10.3389/fpls.2019.00773] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 05/03/2023]
Abstract
During prophase I a meiosis-specific proteinaceous tripartite structure, the synaptonemal complex (SC), forms a scaffold to connect homologous chromosomes along their lengths. This process, called synapsis, is required in most organisms to promote recombination between homologs facilitating genetic variability and correct chromosome segregations during anaphase I. Recent studies in various organisms ranging from yeast to mammals identified several proteins involved in SC formation. However, the process of SC disassembly remains largely enigmatic. In this study we determined the structural changes during SC formation and disassembly in rye meiocytes containing accessory (B) chromosomes. The use of electron and super-resolution microscopy (3D-SIM) combined with immunohistochemistry and FISH allowed us to monitor the structural changes during prophase I. Visualization of the proteins ASY1, ZYP1, NSE4A, and HEI10 revealed an extensive SC remodeling during prophase I. The ultrastructural investigations of the dynamics of these four proteins showed that the SC disassembly is accompanied by the retraction of the lateral and axial elements from the central region of the SC. In addition, SC fragmentation and the formation of ball-like SC structures occur at late diakinesis. Moreover, we show that the SC composition of rye B chromosomes does not differ from that of the standard (A) chromosome complement. Our ultrastructural investigations indicate that the dynamic behavior of the studied proteins is involved in SC formation and synapsis. In addition, they fulfill also functions during desynapsis and chromosome condensation to realize proper recombination and homolog separation. We propose a model for the homologous chromosome behavior during prophase I based on the observed dynamics of ASY1, ZYP1, NSE4A, and HEI10.
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Affiliation(s)
- Susann Hesse
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
| | - Mateusz Zelkowski
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
| | - Elena I. Mikhailova
- N.I.Vavilov Institute of General Genetics, Russian Academy of Sciences, Saint-Petersburg State University, Saint-Petersburg, Russia
| | | | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, Germany
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8
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Brc1 Promotes the Focal Accumulation and SUMO Ligase Activity of Smc5-Smc6 during Replication Stress. Mol Cell Biol 2019; 39:MCB.00271-18. [PMID: 30348841 DOI: 10.1128/mcb.00271-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/12/2018] [Indexed: 11/20/2022] Open
Abstract
As genetic instability drives disease or loss of cell fitness, cellular safeguards have evolved to protect the genome, especially during sensitive cell cycle phases, such as DNA replication. Fission yeast Brc1 has emerged as a key factor in promoting cell survival when replication forks are stalled or collapsed. Brc1 is a multi-BRCT protein that is structurally related to the budding yeast Rtt107 and human PTIP DNA damage response factors, but functional similarities appear limited. Brc1 is a dosage suppressor of a mutation in the essential Smc5-Smc6 genome stability complex and is thought to act in a bypass pathway. In this study, we reveal an unexpectedly intimate connection between Brc1 and Smc5-Smc6 function. Brc1 is required for the accumulation of the Smc5-Smc6 genome stability complex in foci during replication stress and for activation of the intrinsic SUMO ligase activity of the complex by collapsed replication forks. Moreover, we show that the chromatin association and SUMO ligase activity of Smc5-Smc6 require the Nse5-Nse6 heterodimer, explaining how this nonessential cofactor critically supports the DNA repair roles of Smc5-Smc6. We also found that Brc1 interacts with Nse5-Nse6, as well as gamma-H2A, so it can tether Smc5-Smc6 at replicative DNA lesions to promote survival.
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9
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Oravcová M, Boddy MN. Recruitment, loading, and activation of the Smc5-Smc6 SUMO ligase. Curr Genet 2019; 65:669-676. [PMID: 30600397 DOI: 10.1007/s00294-018-0922-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 12/14/2018] [Accepted: 12/15/2018] [Indexed: 12/21/2022]
Abstract
Duplication of the genome poses one of the most significant threats to genetic integrity, cellular fitness, and organismal health. Therefore, numerous mechanisms have evolved that maintain replication fork stability in the face of DNA damage and allow faithful genome duplication. The fission yeast BRCT-domain-containing protein Brc1, and its budding yeast orthologue Rtt107, has emerged as a "hub" factor that integrates multiple replication fork protection mechanisms. Notably, the cofactors and pathways through which Brc1, Rtt107, and their human orthologue (PTIP) act have appeared largely distinct. This either represents true evolutionary functional divergence, or perhaps an incomplete genetic and biochemical analysis of each protein. In this regard, we recently showed that like Rtt107, Brc1 supports key functions of the Smc5-Smc6 complex, including its recruitment into DNA repair foci, chromatin association, and SUMO ligase activity. Furthermore, fission yeast cells lacking the Nse5-Nse6 genome stability factor were found to exhibit defects in Smc5-Smc6 function, similar to but more severe than those in cells lacking Brc1. Here, we place these findings in context with the known functions of Brc1, Rtt107, and Smc5-Smc6, present data suggesting a role for acetylation in Smc5-Smc6 chromatin loading, and discuss wider implications for genome stability.
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Affiliation(s)
- Martina Oravcová
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Michael N Boddy
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
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10
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Kim SM, Forsburg SL. Regulation of Structure-Specific Endonucleases in Replication Stress. Genes (Basel) 2018; 9:genes9120634. [PMID: 30558228 PMCID: PMC6316474 DOI: 10.3390/genes9120634] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/16/2022] Open
Abstract
Replication stress results in various forms of aberrant replication intermediates that need to be resolved for faithful chromosome segregation. Structure-specific endonucleases (SSEs) recognize DNA secondary structures rather than primary sequences and play key roles during DNA repair and replication stress. Holliday junction resolvase MUS81 (methyl methane sulfonate (MMS), and UV-sensitive protein 81) and XPF (xeroderma pigmentosum group F-complementing protein) are a subset of SSEs that resolve aberrant replication structures. To ensure genome stability and prevent unnecessary DNA breakage, these SSEs are tightly regulated by the cell cycle and replication checkpoints. We discuss the regulatory network that control activities of MUS81 and XPF and briefly mention other SSEs involved in the resolution of replication intermediates.
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Affiliation(s)
- Seong Min Kim
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Susan L Forsburg
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
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11
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Hwang G, Verver DE, Handel MA, Hamer G, Jordan PW. Depletion of SMC5/6 sensitizes male germ cells to DNA damage. Mol Biol Cell 2018; 29:3003-3016. [PMID: 30281394 PMCID: PMC6333175 DOI: 10.1091/mbc.e18-07-0459] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The structural maintenance of chromosomes complex SMC5/6 is thought to be essential for DNA repair and chromosome segregation during mitosis and meiosis. To determine the requirements of the SMC5/6 complex during mouse spermatogenesis we combined a conditional knockout allele for Smc5, with four germ cell–specific Cre-recombinase transgenes, Ddx4-Cre, Stra8-Cre, Spo11-Cre, and Hspa2-Cre, to mutate Smc5 in spermatogonia, in spermatocytes before meiotic entry, during early meiotic stages, and during midmeiotic stages, respectively. Conditional mutation of Smc5 resulted in destabilization of the SMC5/6 complex. Despite this, we observed only mild defects in spermatogenesis. Mutation of Smc5 mediated by Ddx4-Cre and Stra8-Cre resulted in partial loss of preleptotene spermatocytes; however, spermatogenesis progresses and mice are fertile. Mutation of Smc5 via Spo11-Cre or Hspa2-Cre did not result in detectable defects of spermatogenesis. Upon exposure to gamma irradiation or etoposide treatment, each conditional Smc5 mutant demonstrated an increase in the number of enlarged round spermatids with multiple acrosomes and supernumerary chromosome content. We propose that the SMC5/6 complex is not acutely required for premeiotic DNA replication and meiotic progression during mouse spermatogenesis; however, when germ cells are challenged by exogenous DNA damage, the SMC5/6 complex ensures genome integrity, and thus, fertility.
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Affiliation(s)
- G Hwang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
| | - D E Verver
- Reproductive Biology Laboratory, Center for Reproductive Medicine, Academic Medical Center, 1105 AZ Amsterdam, the Netherlands
| | - M A Handel
- The Jackson Laboratory, Bar Harbor, ME 04609
| | - G Hamer
- Reproductive Biology Laboratory, Center for Reproductive Medicine, Academic Medical Center, 1105 AZ Amsterdam, the Netherlands
| | - P W Jordan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
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12
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Wani S, Maharshi N, Kothiwal D, Mahendrawada L, Kalaivani R, Laloraya S. Interaction of the Saccharomyces cerevisiae RING-domain protein Nse1 with Nse3 and the Smc5/6 complex is required for chromosome replication and stability. Curr Genet 2017; 64:599-617. [DOI: 10.1007/s00294-017-0776-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 12/17/2022]
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13
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Zheng Y, Jongejan A, Mulder CL, Mastenbroek S, Repping S, Wang Y, Li J, Hamer G. Trivial role for NSMCE2 during in vitro proliferation and differentiation of male germline stem cells. Reproduction 2017; 154:181-195. [DOI: 10.1530/rep-17-0173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/26/2017] [Accepted: 06/02/2017] [Indexed: 12/12/2022]
Abstract
Spermatogenesis, starting with spermatogonial differentiation, is characterized by ongoing and dramatic alterations in composition and function of chromatin. Failure to maintain proper chromatin dynamics during spermatogenesis may lead to mutations, chromosomal aberrations or aneuploidies. When transmitted to the offspring, these can cause infertility or congenital malformations. The structural maintenance of chromosomes (SMC) 5/6 protein complex has recently been described to function in chromatin modeling and genomic integrity maintenance during spermatogonial differentiation and meiosis. Among the subunits of the SMC5/6 complex, non-SMC element 2 (NSMCE2) is an important small ubiquitin-related modifier (SUMO) ligase. NSMCE2 has been reported to be essential for mouse development, prevention of cancer and aging in adult mice and topological stress relief in human somatic cells. By using in vitro cultured primary mouse spermatogonial stem cells (SSCs), referred to as male germline stem (GS) cells, we investigated the function of NSMCE2 during spermatogonial proliferation and differentiation. We first optimized a protocol to generate genetically modified GS cell lines using CRISPR-Cas9 and generated an Nsmce2−/− GS cell line. Using this Nsmce2−/− GS cell line, we found that NSMCE2 was dispensable for proliferation, differentiation and topological stress relief in mouse GS cells. Moreover, RNA sequencing analysis demonstrated that the transcriptome was only minimally affected by the absence of NSMCE2. Only differential expression of Sgsm1 appeared highly significant, but with SGSM1 protein levels being unaffected without NSMCE2. Hence, despite the essential roles of NSMCE2 in somatic cells, chromatin integrity maintenance seems differentially regulated in the germline.
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14
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Dehé PM, Gaillard PHL. Control of structure-specific endonucleases to maintain genome stability. Nat Rev Mol Cell Biol 2017; 18:315-330. [PMID: 28327556 DOI: 10.1038/nrm.2016.177] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Structure-specific endonucleases (SSEs) have key roles in DNA replication, recombination and repair, and emerging roles in transcription. These enzymes have specificity for DNA secondary structure rather than for sequence, and therefore their activity must be precisely controlled to ensure genome stability. In this Review, we discuss how SSEs are controlled as part of genome maintenance pathways in eukaryotes, with an emphasis on the elaborate mechanisms that regulate the members of the major SSE families - including the xeroderma pigmentosum group F-complementing protein (XPF) and MMS and UV-sensitive protein 81 (MUS81)-dependent nucleases, and the flap endonuclease 1 (FEN1), XPG and XPG-like endonuclease 1 (GEN1) enzymes - during processes such as DNA adduct repair, Holliday junction processing and replication stress. We also discuss newly characterized connections between SSEs and other classes of DNA-remodelling enzymes and cell cycle control machineries, which reveal the importance of SSE scaffolds such as the synthetic lethal of unknown function 4 (SLX4) tumour suppressor for the maintenance of genome stability.
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Affiliation(s)
- Pierre-Marie Dehé
- Centre de Recherche en Cancérologie de Marseille, CRCM, CNRS, Aix Marseille Université, INSERM, Institut Paoli-Calmettes, 27 Boulevard Leï Roure, 13009 Marseille, France
| | - Pierre-Henri L Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, CNRS, Aix Marseille Université, INSERM, Institut Paoli-Calmettes, 27 Boulevard Leï Roure, 13009 Marseille, France
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15
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Alt A, Dang HQ, Wells OS, Polo LM, Smith MA, McGregor GA, Welte T, Lehmann AR, Pearl LH, Murray JM, Oliver AW. Specialized interfaces of Smc5/6 control hinge stability and DNA association. Nat Commun 2017; 8:14011. [PMID: 28134253 PMCID: PMC5290277 DOI: 10.1038/ncomms14011] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 11/21/2016] [Indexed: 01/09/2023] Open
Abstract
The Structural Maintenance of Chromosomes (SMC) complexes: cohesin, condensin and Smc5/6 are involved in the organization of higher-order chromosome structure-which is essential for accurate chromosome duplication and segregation. Each complex is scaffolded by a specific SMC protein dimer (heterodimer in eukaryotes) held together via their hinge domains. Here we show that the Smc5/6-hinge, like those of cohesin and condensin, also forms a toroidal structure but with distinctive subunit interfaces absent from the other SMC complexes; an unusual 'molecular latch' and a functional 'hub'. Defined mutations in these interfaces cause severe phenotypic effects with sensitivity to DNA-damaging agents in fission yeast and reduced viability in human cells. We show that the Smc5/6-hinge complex binds preferentially to ssDNA and that this interaction is affected by both 'latch' and 'hub' mutations, suggesting a key role for these unique features in controlling DNA association by the Smc5/6 complex.
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Affiliation(s)
- Aaron Alt
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ, UK
| | - Hung Q. Dang
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Owen S. Wells
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Luis M. Polo
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ, UK
| | - Matt A. Smith
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Grant A. McGregor
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Thomas Welte
- Dynamic Biosensors GmbH, Lochhamer Strasse, D-81252 Martinsreid/Planegg, Germany
| | - Alan R. Lehmann
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H. Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ, UK
| | - Johanne M. Murray
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Antony W. Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ, UK
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16
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Verver DE, Zheng Y, Speijer D, Hoebe R, Dekker HL, Repping S, Stap J, Hamer G. Non-SMC Element 2 (NSMCE2) of the SMC5/6 Complex Helps to Resolve Topological Stress. Int J Mol Sci 2016; 17:ijms17111782. [PMID: 27792189 PMCID: PMC5133783 DOI: 10.3390/ijms17111782] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/14/2016] [Accepted: 10/20/2016] [Indexed: 01/05/2023] Open
Abstract
The structural maintenance of chromosomes (SMC) protein complexes shape and regulate the structure and dynamics of chromatin, thereby controlling many chromosome-based processes such as cell cycle progression, differentiation, gene transcription and DNA repair. The SMC5/6 complex is previously described to promote DNA double-strand breaks (DSBs) repair by sister chromatid recombination, and found to be essential for resolving recombination intermediates during meiotic recombination. Moreover, in budding yeast, SMC5/6 provides structural organization and topological stress relief during replication in mitotically dividing cells. Despite the essential nature of the SMC5/6 complex, the versatile mechanisms by which SMC5/6 functions and its molecular regulation in mammalian cells remain poorly understood. By using a human osteosarcoma cell line (U2OS), we show that after the CRISPR-Cas9-mediated removal of the SMC5/6 subunit NSMCE2, treatment with the topoisomerase II inhibitor etoposide triggered an increased sensitivity in cells lacking NSMCE2. In contrast, NSMCE2 appeared not essential for a proper DNA damage response or cell survival after DSB induction by ionizing irradiation (IR). Interestingly, by way of immunoprecipitations (IPs) and mass spectrometry, we found that the SMC5/6 complex physically interacts with the DNA topoisomerase II α (TOP2A). We therefore propose that the SMC5/6 complex functions in resolving TOP2A-mediated DSB-repair intermediates generated during replication.
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Affiliation(s)
- Dideke E Verver
- Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Yi Zheng
- Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Dave Speijer
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Ron Hoebe
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Henk L Dekker
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, University of Amsterdam, 1090 GE Amsterdam, The Netherlands.
| | - Sjoerd Repping
- Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Jan Stap
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | - Geert Hamer
- Center for Reproductive Medicine, Amsterdam Research Institute Reproduction and Development, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
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17
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Ohta S, Montaño-Gutierrez LF, de Lima Alves F, Ogawa H, Toramoto I, Sato N, Morrison CG, Takeda S, Hudson DF, Rappsilber J, Earnshaw WC. Proteomics Analysis with a Nano Random Forest Approach Reveals Novel Functional Interactions Regulated by SMC Complexes on Mitotic Chromosomes. Mol Cell Proteomics 2016; 15:2802-18. [PMID: 27231315 PMCID: PMC4974353 DOI: 10.1074/mcp.m116.057885] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/04/2016] [Indexed: 12/31/2022] Open
Abstract
Packaging of DNA into condensed chromosomes during mitosis is essential for the faithful segregation of the genome into daughter nuclei. Although the structure and composition of mitotic chromosomes have been studied for over 30 years, these aspects are yet to be fully elucidated. Here, we used stable isotope labeling with amino acids in cell culture to compare the proteomes of mitotic chromosomes isolated from cell lines harboring conditional knockouts of members of the condensin (SMC2, CAP-H, CAP-D3), cohesin (Scc1/Rad21), and SMC5/6 (SMC5) complexes. Our analysis revealed that these complexes associate with chromosomes independently of each other, with the SMC5/6 complex showing no significant dependence on any other chromosomal proteins during mitosis. To identify subtle relationships between chromosomal proteins, we employed a nano Random Forest (nanoRF) approach to detect protein complexes and the relationships between them. Our nanoRF results suggested that as few as 113 of 5058 detected chromosomal proteins are functionally linked to chromosome structure and segregation. Furthermore, nanoRF data revealed 23 proteins that were not previously suspected to have functional interactions with complexes playing important roles in mitosis. Subsequent small-interfering-RNA-based validation and localization tracking by green fluorescent protein-tagging highlighted novel candidates that might play significant roles in mitotic progression.
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Affiliation(s)
- Shinya Ohta
- From the ‡Center for Innovative and Translational Medicine, Medical School, Kochi University Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan; §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK;
| | - Luis F Montaño-Gutierrez
- §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Flavia de Lima Alves
- §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Hiromi Ogawa
- §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK
| | - Iyo Toramoto
- From the ‡Center for Innovative and Translational Medicine, Medical School, Kochi University Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan
| | - Nobuko Sato
- From the ‡Center for Innovative and Translational Medicine, Medical School, Kochi University Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan
| | - Ciaran G Morrison
- ¶Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Shunichi Takeda
- ‖Department of Radiation Genetics, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan
| | - Damien F Hudson
- **Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria 3052, Australia
| | - Juri Rappsilber
- §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK; ‡‡Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - William C Earnshaw
- §Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3BF, UK
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18
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Hong Y, Sonneville R, Agostinho A, Meier B, Wang B, Blow JJ, Gartner A. The SMC-5/6 Complex and the HIM-6 (BLM) Helicase Synergistically Promote Meiotic Recombination Intermediate Processing and Chromosome Maturation during Caenorhabditis elegans Meiosis. PLoS Genet 2016; 12:e1005872. [PMID: 27010650 PMCID: PMC4807058 DOI: 10.1371/journal.pgen.1005872] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/25/2016] [Indexed: 11/19/2022] Open
Abstract
Meiotic recombination is essential for the repair of programmed double strand breaks (DSBs) to generate crossovers (COs) during meiosis. The efficient processing of meiotic recombination intermediates not only needs various resolvases but also requires proper meiotic chromosome structure. The Smc5/6 complex belongs to the structural maintenance of chromosome (SMC) family and is closely related to cohesin and condensin. Although the Smc5/6 complex has been implicated in the processing of recombination intermediates during meiosis, it is not known how Smc5/6 controls meiotic DSB repair. Here, using Caenorhabditis elegans we show that the SMC-5/6 complex acts synergistically with HIM-6, an ortholog of the human Bloom syndrome helicase (BLM) during meiotic recombination. The concerted action of the SMC-5/6 complex and HIM-6 is important for processing recombination intermediates, CO regulation and bivalent maturation. Careful examination of meiotic chromosomal morphology reveals an accumulation of inter-chromosomal bridges in smc-5; him-6 double mutants, leading to compromised chromosome segregation during meiotic cell divisions. Interestingly, we found that the lethality of smc-5; him-6 can be rescued by loss of the conserved BRCA1 ortholog BRC-1. Furthermore, the combined deletion of smc-5 and him-6 leads to an irregular distribution of condensin and to chromosome decondensation defects reminiscent of condensin depletion. Lethality conferred by condensin depletion can also be rescued by BRC-1 depletion. Our results suggest that SMC-5/6 and HIM-6 can synergistically regulate recombination intermediate metabolism and suppress ectopic recombination by controlling chromosome architecture during meiosis.
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Affiliation(s)
- Ye Hong
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Remi Sonneville
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Ana Agostinho
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Bin Wang
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
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19
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Abstract
The study of homologous recombination has its historical roots in meiosis. In this context, recombination occurs as a programmed event that culminates in the formation of crossovers, which are essential for accurate chromosome segregation and create new combinations of parental alleles. Thus, meiotic recombination underlies both the independent assortment of parental chromosomes and genetic linkage. This review highlights the features of meiotic recombination that distinguish it from recombinational repair in somatic cells, and how the molecular processes of meiotic recombination are embedded and interdependent with the chromosome structures that characterize meiotic prophase. A more in-depth review presents our understanding of how crossover and noncrossover pathways of meiotic recombination are differentiated and regulated. The final section of this review summarizes the studies that have defined defective recombination as a leading cause of pregnancy loss and congenital disease in humans.
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Affiliation(s)
- Neil Hunter
- Howard Hughes Medical Institute, Department of Microbiology & Molecular Genetics, Department of Molecular & Cellular Biology, Department of Cell Biology & Human Anatomy, University of California Davis, Davis, California 95616
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20
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Sánchez A, Russell P. Ku stabilizes replication forks in the absence of Brc1. PLoS One 2015; 10:e0126598. [PMID: 25965521 PMCID: PMC4428774 DOI: 10.1371/journal.pone.0126598] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/05/2015] [Indexed: 11/21/2022] Open
Abstract
DNA replication errors are a major source of genome instability in all organisms. In the fission yeast Schizosaccharomyces pombe, the DNA damage response protein Brc1 binds phospho-histone H2A (γH2A)-marked chromatin during S-phase, but how Brc1 protects genome integrity remains unclear. Here we report that the non-homologous end-joining (NHEJ) protein Ku becomes critical for survival of replication stress in brc1∆ cells. Ku’s protective activity in brc1∆ cells does not involve its canonical NHEJ function or its roles in protecting telomeres or shielding DNA ends from Exo1 exonuclease. In brc1∆ pku80∆ cells, nuclear foci of Rad52 homologous recombination (HR) protein increase and Mus81-Eme1 Holliday junction resolvase becomes critical, indicating increased replication fork instability. Ku’s localization at a ribosomal DNA replication fork barrier associated with frequent replisome-transcriptosome collisions increases in brc1∆ cells and increased collisions correlate with an enhanced requirement for Brc1. These data indicate that Ku stabilizes replication forks in the absence of Brc1.
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Affiliation(s)
- Arancha Sánchez
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paul Russell
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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21
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Resolving complex chromosome structures during meiosis: versatile deployment of Smc5/6. Chromosoma 2015; 125:15-27. [PMID: 25947290 PMCID: PMC4761004 DOI: 10.1007/s00412-015-0518-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/02/2015] [Accepted: 04/20/2015] [Indexed: 12/25/2022]
Abstract
The Smc5/6 complex, along with cohesin and condensin, is a member of the structural maintenance of chromosome (SMC) family, large ring-like protein complexes that are essential for chromatin structure and function. Thanks to numerous studies of the mitotic cell cycle, Smc5/6 has been implicated to have roles in homologous recombination, restart of stalled replication forks, maintenance of ribosomal DNA (rDNA) and heterochromatin, telomerase-independent telomere elongation, and regulation of chromosome topology. The nature of these functions implies that the Smc5/6 complex also contributes to the profound chromatin changes, including meiotic recombination, that characterize meiosis. Only recently, studies in diverse model organisms have focused on the potential meiotic roles of the Smc5/6 complex. Indeed, Smc5/6 appears to be essential for meiotic recombination. However, due to both the complexity of the process of meiosis and the versatility of the Smc5/6 complex, many additional meiotic functions have been described. In this review, we provide a clear overview of the multiple functions found so far for the Smc5/6 complex in meiosis. Additionally, we compare these meiotic functions with the known mitotic functions in an attempt to find a common denominator and thereby create clarity in the field of Smc5/6 research.
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22
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Bermúdez-López M, Pociño-Merino I, Sánchez H, Bueno A, Guasch C, Almedawar S, Bru-Virgili S, Garí E, Wyman C, Reverter D, Colomina N, Torres-Rosell J. ATPase-dependent control of the Mms21 SUMO ligase during DNA repair. PLoS Biol 2015; 13:e1002089. [PMID: 25764370 PMCID: PMC4357442 DOI: 10.1371/journal.pbio.1002089] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Modification of proteins by SUMO is essential for the maintenance of genome integrity. During DNA replication, the Mms21-branch of the SUMO pathway counteracts recombination intermediates at damaged replication forks, thus facilitating sister chromatid disjunction. The Mms21 SUMO ligase docks to the arm region of the Smc5 protein in the Smc5/6 complex; together, they cooperate during recombinational DNA repair. Yet how the activity of the SUMO ligase is controlled remains unknown. Here we show that the SUMO ligase and the chromosome disjunction functions of Mms21 depend on its docking to an intact and active Smc5/6 complex, indicating that the Smc5/6-Mms21 complex operates as a large SUMO ligase in vivo. In spite of the physical distance separating the E3 and the nucleotide-binding domains in Smc5/6, Mms21-dependent sumoylation requires binding of ATP to Smc5, a step that is part of the ligase mechanism that assists Ubc9 function. The communication is enabled by the presence of a conserved disruption in the coiled coil domain of Smc5, pointing to potential conformational changes for SUMO ligase activation. In accordance, scanning force microscopy of the Smc5-Mms21 heterodimer shows that the molecule is physically remodeled in an ATP-dependent manner. Our results demonstrate that the ATP-binding activity of the Smc5/6 complex is coordinated with its SUMO ligase, through the coiled coil domain of Smc5 and the physical remodeling of the molecule, to promote sumoylation and chromosome disjunction during DNA repair. Conserved conformational joints in the Mms21-Smc5/6 complex allow coordination between its ATPase and E3 SUMO ligase activities, integrating its structural and signaling roles during DNA repair to allow correct chromosome separation. The modification of target proteins by conjugation to SUMO—a small protein that acts as a regulatory tag—is essential for maintaining the integrity of genomes in most eukaryotic organisms. One critical step during the attachment of SUMO is the activation of the enzymes that catalyze this reaction—E1, E2, and the SUMO ligases. However, we currently do not fully understand how the different enzymes in the SUMO pathway are regulated. The SUMO ligase Mms21 is known to bind to Smc5/6, a large protein complex involved in the structural maintenance of chromosomes. Both Mms21 and Smc5/6 counteract the accumulation of recombination intermediates, which otherwise join replicated chromosomes, preventing their separation. Not surprisingly, the few known targets of the Mms21 ligase are mostly related to the repair of sister chromatids by recombination. Here, we show that the Mms21 SUMO ligase needs to bind to the Smc5/6 complex to promote chromosome separation. We used two Mms21-dependent SUMO conjugation targets—Smc5 and cohesin—to study the connection between the Mms21’s SUMO ligase activity and its binding partner, Smc5/6. Our results indicated that Mms21 activation is tightly coordinated with the intrinsic ATPase function of the Smc5/6 complex. However, the SUMO ligase and the ATPase lie in different domains of the Smc5/6-Mms21 complex that are normally distant from each other; we show that communication between these enzyme sites is enabled by the presence of conserved joints, which we suggest allow the necessary conformational changes required for SUMO ligase activation. This coordination of activities is extremely helpful for the cell, enabling it to integrate a structural role on chromatin during DNA repair with a signaling function, thereby promoting correct separation of the chromosomes.
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Affiliation(s)
| | - Irene Pociño-Merino
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Humberto Sánchez
- Department of Genetics and Radiation Oncology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Andrés Bueno
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Clàudia Guasch
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Seba Almedawar
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Sergi Bru-Virgili
- Institut de Biotecnologia i Biomedicina, Dept. de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Eloi Garí
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Claire Wyman
- Department of Genetics and Radiation Oncology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - David Reverter
- Institut de Biotecnologia i Biomedicina, Dept. de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Neus Colomina
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
| | - Jordi Torres-Rosell
- IRBLLEIDA, Dept. Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
- * E-mail:
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23
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Mus81-Mms4 and Yen1 resolve a novel anaphase bridge formed by noncanonical Holliday junctions. Nat Commun 2014; 5:5652. [PMID: 25466415 DOI: 10.1038/ncomms6652] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 10/24/2014] [Indexed: 02/07/2023] Open
Abstract
Downregulation of separase, condensin, Smc5/6, topoisomerase II and Cdc14 in Saccharomyces cerevisiae yields anaphase bridges formed by unresolved sister chromatids (SCBs). Here we report that the overlapping actions of the structure-selective endonucleases (SSEs) Mus81-Mms4/EME1 and Yen1/GEN1, but not Slx1-Slx4, are also essential to prevent the formation of spontaneous SCBs that depend on the homologous recombination pathway. We further show that the frequency of SCBs is boosted after mild replication stress and that they contain joint molecules enriched in non-canonical forms of the Holliday junction (HJ), including nicked-HJ (nHJ). We show that SCBs are mostly reversible upon activation of either Mus81-Mms4 or Yen1 in late anaphase, which is concomitant with the disappearance of non-canonical HJs and restoration of viable progeny. On the basis of these findings, we propose a model where unresolved recombination intermediates are a source of mitotic SCBs, and Mus81-Mms4 and Yen1 play a central role in their resolution in vivo.
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24
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Verver DE, Langedijk NSM, Jordan PW, Repping S, Hamer G. The SMC5/6 complex is involved in crucial processes during human spermatogenesis. Biol Reprod 2014; 91:22. [PMID: 24855106 PMCID: PMC6058740 DOI: 10.1095/biolreprod.114.118596] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Genome integrity is crucial for safe reproduction. Therefore, chromatin structure and dynamics should be tightly regulated during germ cell development. Chromatin structure and function are in large part determined by the structural maintenance of chromosomes (SMC) protein complexes, of which SMC5/6 recently has been shown to be involved in both spermatogonial differentiation and meiosis during mouse spermatogenesis. We therefore investigated the role of this complex in human spermatogenesis. We found SMC6 to be expressed in the human testis and present in a subset of type Adark and type Apale spermatogonia, all spermatocytes, and round spermatids. During human meiosis, SMC5/6 is located at the synaptonemal complex (SC), the XY body, and at the centromeres during meiotic metaphases. However, in contrast to mouse spermatogenesis, SMC6 is not located at pericentromeric heterochromatin in human spermatogenic cells, indicating subtle but perhaps important differences in not only SMC5/6 function but maybe also in maintenance of genomic integrity at the repetitive pericentromeric regions. Nonetheless, our data clearly indicate that the SMC5/6 complex, as shown in mice, is involved in numerous crucial processes during human spermatogenesis, such as in spermatogonial development, on the SC between synapsed chromosomes, and in DNA double-strand break repair on unsynapsed chromosomes during pachynema.
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Affiliation(s)
- Dideke E Verver
- Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Nathalia S M Langedijk
- Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Philip W Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Sjoerd Repping
- Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Geert Hamer
- Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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25
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Xaver M, Huang L, Chen D, Klein F. Smc5/6-Mms21 prevents and eliminates inappropriate recombination intermediates in meiosis. PLoS Genet 2013; 9:e1004067. [PMID: 24385936 PMCID: PMC3873250 DOI: 10.1371/journal.pgen.1004067] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 11/13/2013] [Indexed: 01/05/2023] Open
Abstract
Repairing broken chromosomes via joint molecule (JM) intermediates is hazardous and therefore strictly controlled in most organisms. Also in budding yeast meiosis, where production of enough crossovers via JMs is imperative, only a subset of DNA breaks are repaired via JMs, closely regulated by the ZMM pathway. The other breaks are repaired to non-crossovers, avoiding JM formation, through pathways that require the BLM/Sgs1 helicase. “Rogue” JMs that escape the ZMM pathway and BLM/Sgs1 are eliminated before metaphase by resolvases like Mus81-Mms4 to prevent chromosome nondisjunction. Here, we report the requirement of Smc5/6-Mms21 for antagonizing rogue JMs via two mechanisms; destabilizing early intermediates and resolving JMs. Elimination of the Mms21 SUMO E3-ligase domain leads to transient JM accumulation, depending on Mus81-Mms4 for resolution. Absence of Smc6 leads to persistent rogue JMs accumulation, preventing chromatin separation. We propose that the Smc5/6-Mms21 complex antagonizes toxic JMs by coordinating helicases and resolvases at D-Loops and HJs, respectively. Homologous recombination allows repair of DNA breaks from intact templates of identical sequence by a “copy-and-paste” like mechanism. However, the double Holliday Junction (dHJ) is a hazardous intermediate that can form during homologous recombination, if single stranded DNA from both ends of a lesion pair with the template. Once the primary lesion is eliminated, the dHJ connects the chromosomes stably and if unresolved can prevent segregation during cell division. In order to prevent chromosome non-disjunction, resolvases will cut any HJ before division. However, genomes contain many multi-copy DNA sequences as transposons or repetitive elements. If dHJs form between such non-allelic loci, cleavage by resolvases can result in chromosome translocations and deletions. Therefore, stabilization of dHJs is sought to be avoided in the first instance by anti-recombinogenic helicases on early intermediates. Analysis of Smc5/6-Mms21 mutants in meiosis revealed that it antagonizes unregulated dHJs both by prevention and resolution. Elimination of the Mms21 SUMO E3-ligase domain leads to inappropriate dHJ accumulation still resolved by Mus81-Mms4. Disruption of the whole complex results in persistent dHJ accumulation and dysfunction of resolvases, preventing chromatin segregation. These results provide a first unified view on the function of Smc5/6-Mms21 as an antagonist of dangerous dHJs.
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Affiliation(s)
- Martin Xaver
- Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna, Austria
- * E-mail: (MX); (FK)
| | - Lingzhi Huang
- Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Doris Chen
- Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Franz Klein
- Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna, Austria
- * E-mail: (MX); (FK)
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26
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Copsey A, Tang S, Jordan PW, Blitzblau HG, Newcombe S, Chan ACH, Newnham L, Li Z, Gray S, Herbert AD, Arumugam P, Hochwagen A, Hunter N, Hoffmann E. Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions. PLoS Genet 2013; 9:e1004071. [PMID: 24385939 PMCID: PMC3873251 DOI: 10.1371/journal.pgen.1004071] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 11/08/2013] [Indexed: 11/22/2022] Open
Abstract
During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4(Eme1). Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastrophe.
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Affiliation(s)
- Alice Copsey
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Shangming Tang
- Howard Hughes Medical Institute, University of California, Davis, Davis, California, United States of America
- Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, California, United States of America
| | - Philip W. Jordan
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Hannah G. Blitzblau
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Sonya Newcombe
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Andrew Chi-ho Chan
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Louise Newnham
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Zhaobo Li
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Stephen Gray
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Alex D. Herbert
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
| | - Prakash Arumugam
- Department of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Andreas Hochwagen
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
- Department of Biology, New York University, New York, New York, United States of America
| | - Neil Hunter
- Howard Hughes Medical Institute, University of California, Davis, Davis, California, United States of America
- Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, California, United States of America
- Department of Biology, New York University, New York, New York, United States of America
- Department of Molecular & Cellular Biology, University of California, Davis, Davis, California, United States of America
- Department of Cell Biology & Human Anatomy, University of California, Davis, Davis, California, United States of America
| | - Eva Hoffmann
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton, United Kingdom
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27
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Lilienthal I, Kanno T, Sjögren C. Inhibition of the Smc5/6 complex during meiosis perturbs joint molecule formation and resolution without significantly changing crossover or non-crossover levels. PLoS Genet 2013; 9:e1003898. [PMID: 24244180 PMCID: PMC3820751 DOI: 10.1371/journal.pgen.1003898] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 09/04/2013] [Indexed: 11/19/2022] Open
Abstract
Meiosis is a specialized cell division used by diploid organisms to form haploid gametes for sexual reproduction. Central to this reductive division is repair of endogenous DNA double-strand breaks (DSBs) induced by the meiosis-specific enzyme Spo11. These DSBs are repaired in a process called homologous recombination using the sister chromatid or the homologous chromosome as a repair template, with the homolog being the preferred substrate during meiosis. Specific products of inter-homolog recombination, called crossovers, are essential for proper homolog segregation at the first meiotic nuclear division in budding yeast and mice. This study identifies an essential role for the conserved Structural Maintenance of Chromosomes (SMC) 5/6 protein complex during meiotic recombination in budding yeast. Meiosis-specific smc5/6 mutants experience a block in DNA segregation without hindering meiotic progression. Establishment and removal of meiotic sister chromatid cohesin are independent of functional Smc6 protein. smc6 mutants also have normal levels of DSB formation and repair. Eliminating DSBs rescues the segregation block in smc5/6 mutants, suggesting that the complex has a function during meiotic recombination. Accordingly, smc6 mutants accumulate high levels of recombination intermediates in the form of joint molecules. Many of these joint molecules are formed between sister chromatids, which is not normally observed in wild-type cells. The normal formation of crossovers in smc6 mutants supports the notion that mainly inter-sister joint molecule resolution is impaired. In addition, return-to-function studies indicate that the Smc5/6 complex performs its most important functions during joint molecule resolution without influencing crossover formation. These results suggest that the Smc5/6 complex aids primarily in the resolution of joint molecules formed outside of canonical inter-homolog pathways. Most eukaryotic cells are diploid, which means that they contain two copies of each chromosome – one from each parent. In order to preserve the chromosome number from generation to generation, diploid organisms employ a process called meiosis to form gametes containing only one copy of each chromosome. During sexual reproduction, two gametes (sperm and eggs in mammals) fuse to form a zygote with the same chromosome number as the parents. This zygote will develop into a new organism that has genetic characteristics unique from, but still related to, both parents. The reduction of chromosome number and the reshuffling of genetic traits during meiosis depend on the repair of naturally occurring DNA breaks. Improper break repair during meiosis may block meiosis altogether or form genetically instable gametes, leading to fertility problems or defects in the offspring. The study presented here demonstrates the importance of the evolutionarily conserved Smc5/6 protein complex in upholding the integrity of meiotic repair processes. Our results show that cells deficient in components of the Smc5/6 complex lead to inviable meiotic products. Cells lacking functional Smc5/6 complex are unable to direct DNA repair to the proper template and accumulate abnormal repair intermediates, which inhibit the reductive division.
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Affiliation(s)
- Ingrid Lilienthal
- Karolinska Institutet, Department of Cell and Molecular Biology, Stockholm, Sweden
| | - Takaharu Kanno
- Karolinska Institutet, Department of Cell and Molecular Biology, Stockholm, Sweden
| | - Camilla Sjögren
- Karolinska Institutet, Department of Cell and Molecular Biology, Stockholm, Sweden
- * E-mail:
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28
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Lukaszewicz A, Howard-Till RA, Loidl J. Mus81 nuclease and Sgs1 helicase are essential for meiotic recombination in a protist lacking a synaptonemal complex. Nucleic Acids Res 2013; 41:9296-309. [PMID: 23935123 PMCID: PMC3814389 DOI: 10.1093/nar/gkt703] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 11/18/2022] Open
Abstract
Mus81 resolvase and Sgs1 helicase have well-established roles in mitotic DNA repair. Moreover, Mus81 is part of a minor crossover (CO) pathway in the meiosis of budding yeast, plants and vertebrates. The major pathway depends on meiosis-specific synaptonemal complex (SC) formation, ZMM proteins and the MutLγ complex for CO-directed resolution of joint molecule (JM)-recombination intermediates. Sgs1 has also been implicated in this pathway, although it may mainly promote the non-CO outcome of meiotic repair. We show in Tetrahymena, that homologous chromosomes fail to separate and JMs accumulate in the absence of Mus81 or Sgs1, whereas deletion of the MutLγ-component Mlh1 does not affect meiotic divisions. Thus, our results are consistent with Mus81 being part of an essential, if not the predominant, CO pathway in Tetrahymena. Sgs1 may exert functions similar to those in other eukaryotes. However, we propose an additional role in supporting homologous CO formation by promoting homologous over intersister interactions. Tetrahymena shares the predominance of the Mus81 CO pathway with the fission yeast. We propose that in these two organisms, which independently lost the SC during evolution, the basal set of mitotic repair proteins is sufficient for executing meiotic recombination.
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Affiliation(s)
| | | | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
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29
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Verver DE, van Pelt AMM, Repping S, Hamer G. Role for rodent Smc6 in pericentromeric heterochromatin domains during spermatogonial differentiation and meiosis. Cell Death Dis 2013; 4:e749. [PMID: 23907463 PMCID: PMC3763431 DOI: 10.1038/cddis.2013.269] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/14/2013] [Accepted: 06/19/2013] [Indexed: 01/08/2023]
Abstract
Chromatin structure and function are for a large part determined by the six members of the structural maintenance of chromosomes (SMC) protein family, which form three heterodimeric complexes: Smc1/3 (cohesin), Smc2/4 (condensin) and Smc5/6. Each complex has distinct and important roles in chromatin dynamics, gene expression and differentiation. In yeast and Drosophila, Smc6 is involved in recombinational repair, restarting collapsed replication forks and prevention of recombination in repetitive sequences such as rDNA and pericentromeric heterochromatin. Although such DNA damage control mechanisms, as well as highly dynamic changes in chromatin composition and function, are essential for gametogenesis, knowledge on Smc6 function in mammalian systems is limited. We therefore have investigated the role of Smc6 during mammalian spermatogonial differentiation, meiosis and subsequent spermiogenesis. We found that, during mouse spermatogenesis, Smc6 functions as part of meiotic pericentromeric heterochromatin domains that are initiated when differentiating spermatogonia become irreversibly committed toward meiosis. To our knowledge, we are the first to provide insight into how commitment toward meiosis alters chromatin structure and dynamics, thereby setting apart differentiating spermatogonia from the undifferentiated spermatogonia, including the spermatogonial stem cells. Interestingly, Smc6 is not essential for spermatogonial mitosis, whereas Smc6-negative meiotic cells appear unable to finish their first meiotic division. Importantly, during meiosis, we find that DNA repair or recombination sites, marked by γH2AX or Rad51 respectively, do not co-localize with the pericentromeric heterochromatin domains where Smc6 is located. Considering the repetitive nature of these domains and that Smc6 has been previously shown to prevent recombination in repetitive sequences, we hypothesize that Smc6 has a role in the prevention of aberrant recombination events between pericentromeric regions during the first meiotic prophase that would otherwise cause chromosomal aberrations leading to apoptosis, meiotic arrest or aneuploidies.
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Affiliation(s)
- D E Verver
- Center for Reproductive Medicine, Women's and Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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30
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Gómez R, Jordan PW, Viera A, Alsheimer M, Fukuda T, Jessberger R, Llano E, Pendás AM, Handel MA, Suja JA. Dynamic localization of SMC5/6 complex proteins during mammalian meiosis and mitosis suggests functions in distinct chromosome processes. J Cell Sci 2013; 126:4239-52. [PMID: 23843628 DOI: 10.1242/jcs.130195] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Four members of the structural maintenance of chromosome (SMC) protein family have essential functions in chromosome condensation (SMC2/4) and sister-chromatid cohesion (SMC1/3). The SMC5/6 complex has been implicated in chromosome replication, DNA repair and chromosome segregation in somatic cells, but its possible functions during mammalian meiosis are unknown. Here, we show in mouse spermatocytes that SMC5 and SMC6 are located at the central region of the synaptonemal complex from zygotene until diplotene. During late diplotene both proteins load to the chromocenters, where they colocalize with DNA Topoisomerase IIα, and then accumulate at the inner domain of the centromeres during the first and second meiotic divisions. Interestingly, SMC6 and DNA Topoisomerase IIα colocalize at stretched strands that join kinetochores during the metaphase II to anaphase II transition, and both are observed on stretched lagging chromosomes at anaphase II following treatment with Etoposide. During mitosis, SMC6 and DNA Topoisomerase IIα colocalize at the centromeres and chromatid axes. Our results are consistent with the participation of SMC5 and SMC6 in homologous chromosome synapsis during prophase I, chromosome and centromere structure during meiosis I and mitosis and, with DNA Topoisomerase IIα, in regulating centromere cohesion during meiosis II.
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Affiliation(s)
- Rocío Gómez
- Departamento de Biología, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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31
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Yong-Gonzales V, Hang LE, Castellucci F, Branzei D, Zhao X. The Smc5-Smc6 complex regulates recombination at centromeric regions and affects kinetochore protein sumoylation during normal growth. PLoS One 2012; 7:e51540. [PMID: 23284708 PMCID: PMC3527468 DOI: 10.1371/journal.pone.0051540] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 11/08/2012] [Indexed: 11/22/2022] Open
Abstract
The Smc5-Smc6 complex in Saccharomyces cerevisiae is both essential for growth and important for coping with genotoxic stress. While it facilitates damage tolerance throughout the genome under genotoxin treatment, its function during unperturbed growth is mainly documented for repetitive DNA sequence maintenance. Here we provide physical and genetic evidence showing that the Smc5–Smc6 complex regulates recombination at non-repetitive loci such as centromeres in the absence of DNA damaging agents. Mutating Smc6 results in the accumulation of recombination intermediates at centromeres and other unique sequences as assayed by 2D gel analysis. In addition, smc6 mutant cells exhibit increased levels of Rad52 foci that co-localize with centromere markers. A rad52 mutation that decreases centromeric, but not overall, levels of Rad52 foci in smc6 mutants suppresses the nocodazole sensitivity of these cells, suggesting that the Smc6-mediated regulation of recombination at centromeric regions impacts centromere-related functions. In addition to influencing recombination, the SUMO ligase subunit of the Smc5–Smc6 complex promotes the sumoylation of two kinetochore proteins and affects mitotic spindles. These results suggest that the Smc5–Smc6 complex regulates both recombination and kinetochore sumoylation to facilitate chromosomal maintenance during growth.
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Affiliation(s)
- Vladimir Yong-Gonzales
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Lisa E. Hang
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Programs in Biochemistry, Cell and Molecular Biology, Weill Cornell Graduate School of Medical Sciences, New York, New York, United States of America
| | | | - Dana Branzei
- IFOM, FIRC Institute of Molecular Oncology, Milan, Italy
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail:
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32
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Zilio N, Wehrkamp-Richter S, Boddy MN. A new versatile system for rapid control of gene expression in the fission yeast Schizosaccharomyces pombe. Yeast 2012; 29:425-34. [PMID: 22968950 DOI: 10.1002/yea.2920] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/08/2012] [Accepted: 08/22/2012] [Indexed: 11/11/2022] Open
Abstract
The ability to regulate the expression of a gene greatly aids the process of uncovering its functions. The fission yeast Schizosaccharomyces pombe has so far lacked a system for rapidly controlling the expression of chromosomal genes, hindering its full potential as a model organism. Although the widely used nmt1 promoter displays a wide dynamic range of activity, it takes > 14-15 h to derepress. The urg1 promoter also shows a large dynamic range and can be induced quickly (< 2 h), but its implementation requires laborious strain construction and it cannot be used to study meiosis. To overcome these limitations, we constructed a tetracycline-regulated system for inducible expression of chromosomal genes in fission yeast, which is easily established and implemented. In this system the promoter of a gene is replaced by simple one-step substitution techniques with a tetracycline-regulated promoter cassette (tetO(7) -TATA(CYC1) ) in cells where TetR/TetR'-based transcription activators/repressors are also produced. Using top1 and nse6 as reporter genes, we show that Top1 and Nse6 appear after just 30 min of activating tetO(7) -TATA(CYC1) and plateau after -4-6 h. The amount of synthesised protein is comparable to that produced from the attenuated nmt1 promoter P(nmt8) , which should be closer to wild-type levels for most genes than those generated from excessively strong promoters and can be controlled by changing the concentration of the effector antibiotic. This system also works efficiently during meiosis, thus making it a useful addition to the toolkit of the fission yeast community.
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Affiliation(s)
- Nicola Zilio
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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