1
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Zhang X, Chen X, Lu L, Fang Q, Liu C, Lin Z. Identification of small-molecule inhibitors of human MUS81-EME1/2 by FRET-based high-throughput screening. Bioorg Med Chem 2023; 90:117383. [PMID: 37352577 DOI: 10.1016/j.bmc.2023.117383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 06/09/2023] [Accepted: 06/17/2023] [Indexed: 06/25/2023]
Abstract
The MUS81-EME1/2 structure-specific endonucleases play a crucial role in the processing of stalled replication forks and recombination intermediates, and have been recognized as an attractive drug target to potentiate the anti-cancer efficacy of DNA-damaging agents. Currently, no bioactive small-molecule inhibitors of MUS81 are available. Here, we performed a high-throughput small-molecule inhibitors screening, using the FRET-based DNA cleavage assay. From 7920 compounds, we identified dyngo-4a as a potent inhibitor of MUS81 complexes. Dyngo-4a effectively inhibits the endonuclease activities of both MUS81-EME1 and MUS81-EME2 complexes, with IC50 values of 0.57 μM and 2.90 μM, respectively. Surface plasmon resonance (SPR) and electrophoretic mobility shift assay (EMSA) assays reveal that dyngo-4a directly binds to MUS81 complexes (KD ∼ 0.61 μM) and prevents them from binding to DNA substrates. In HeLa cells, dyngo-4a significantly suppresses bleomycin-triggered H2AX serine 139 phosphorylation (γH2AX). Together, our results demonstrate that dyngo-4a is a potent MUS81 inhibitor, which could be further developed as a potentially valuable chemical tool to explore more physiological roles of MUS81 in the cells.
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Affiliation(s)
- Xu Zhang
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Xuening Chen
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Lian Lu
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Qianqian Fang
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Chun Liu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Zhonghui Lin
- College of Chemistry, Fuzhou University, Fuzhou 350108, China; Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fuzhou, China.
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2
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Marini V, Nikulenkov F, Samadder P, Juul S, Knudsen BR, Krejci L. MUS81 cleaves TOP1-derived lesions and other DNA-protein cross-links. BMC Biol 2023; 21:110. [PMID: 37194054 DOI: 10.1186/s12915-023-01614-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 05/04/2023] [Indexed: 05/18/2023] Open
Abstract
BACKGROUND DNA-protein cross-links (DPCs) are one of the most deleterious DNA lesions, originating from various sources, including enzymatic activity. For instance, topoisomerases, which play a fundamental role in DNA metabolic processes such as replication and transcription, can be trapped and remain covalently bound to DNA in the presence of poisons or nearby DNA damage. Given the complexity of individual DPCs, numerous repair pathways have been described. The protein tyrosyl-DNA phosphodiesterase 1 (Tdp1) has been demonstrated to be responsible for removing topoisomerase 1 (Top1). Nevertheless, studies in budding yeast have indicated that alternative pathways involving Mus81, a structure-specific DNA endonuclease, could also remove Top1 and other DPCs. RESULTS This study shows that MUS81 can efficiently cleave various DNA substrates modified by fluorescein, streptavidin or proteolytically processed topoisomerase. Furthermore, the inability of MUS81 to cleave substrates bearing native TOP1 suggests that TOP1 must be either dislodged or partially degraded prior to MUS81 cleavage. We demonstrated that MUS81 could cleave a model DPC in nuclear extracts and that depletion of TDP1 in MUS81-KO cells induces sensitivity to the TOP1 poison camptothecin (CPT) and affects cell proliferation. This sensitivity is only partially suppressed by TOP1 depletion, indicating that other DPCs might require the MUS81 activity for cell proliferation. CONCLUSIONS Our data indicate that MUS81 and TDP1 play independent roles in the repair of CPT-induced lesions, thus representing new therapeutic targets for cancer cell sensitisation in combination with TOP1 inhibitors.
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Affiliation(s)
- Victoria Marini
- Department of Biology, Masaryk University, Kamenice 5/B07, Brno, 62500, Czech Republic
- International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Pekařská 53, Brno, 60200, Czech Republic
| | - Fedor Nikulenkov
- Department of Biology, Masaryk University, Kamenice 5/B07, Brno, 62500, Czech Republic
| | - Pounami Samadder
- Department of Biology, Masaryk University, Kamenice 5/B07, Brno, 62500, Czech Republic
| | - Sissel Juul
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, Aarhus, 8000, Denmark
| | - Birgitta R Knudsen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, Aarhus, 8000, Denmark
| | - Lumir Krejci
- Department of Biology, Masaryk University, Kamenice 5/B07, Brno, 62500, Czech Republic.
- International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Pekařská 53, Brno, 60200, Czech Republic.
- National Centre for Biomolecular Research, Masaryk University, Kamenice 5/C04, Brno, 625 00, Czech Republic.
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3
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Li S, Mutchler A, Zhu X, So S, Epps J, Guan D, Zhao X, Xue X. Multi-faceted regulation of the sumoylation of the Sgs1 DNA helicase. J Biol Chem 2022; 298:102092. [PMID: 35654140 PMCID: PMC9243176 DOI: 10.1016/j.jbc.2022.102092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 11/27/2022] Open
Abstract
Homologous recombination repairs DNA breaks and sequence gaps via the production of joint DNA intermediates such as Holliday junctions. Dissolving Holliday junctions into linear DNA repair products requires the activity of the Sgs1 helicase in yeast and of its homologs in other organisms. Recent studies suggest that the functions of these conserved helicases are regulated by sumoylation; however, the mechanisms that promote their sumoylation are not well understood. Here, we employed in vitro sumoylation systems and cellular assays to determine the roles of DNA and the scaffold protein Esc2 in Sgs1 sumoylation. We show that DNA binding enhances Sgs1 sumoylation in vitro. In addition, we demonstrate the Esc2’s midregion (MR) with DNA-binding activity is required for Sgs1 sumoylation. Unexpectedly, we found that the sumoylation-promoting effect of Esc2-MR is DNA independent, suggesting a second function for this domain. In agreement with our biochemical data, we found the Esc2-MR domain, like its SUMO E2-binding C-terminal domain characterized in previous studies, is required for proficient sumoylation of Sgs1 and its cofactors, Top3 and Rmi1, in cells. Taken together, these findings provide evidence that while DNA binding enhances Sgs1 sumoylation, Esc2-based stimulation of this modification is mediated by two distinct domains.
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Affiliation(s)
- Shibai Li
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ashley Mutchler
- Materials Science, Engineering, and Commercialization Program, Texas State University, San Marcos, TX 78666, USA
| | - Xinji Zhu
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Stephen So
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - John Epps
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Danying Guan
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaolan Zhao
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Xiaoyu Xue
- Materials Science, Engineering, and Commercialization Program, Texas State University, San Marcos, TX 78666, USA; Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA.
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4
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Regulation of Mus81-Eme1 structure-specific endonuclease by Eme1 SUMO-binding and Rad3ATR kinase is essential in the absence of Rqh1BLM helicase. PLoS Genet 2022; 18:e1010165. [PMID: 35452455 PMCID: PMC9032445 DOI: 10.1371/journal.pgen.1010165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 03/25/2022] [Indexed: 11/25/2022] Open
Abstract
The Mus81-Eme1 structure-specific endonuclease is crucial for the processing of DNA recombination and late replication intermediates. In fission yeast, stimulation of Mus81-Eme1 in response to DNA damage at the G2/M transition relies on Cdc2CDK1 and DNA damage checkpoint-dependent phosphorylation of Eme1 and is critical for chromosome stability in absence of the Rqh1BLM helicase. Here we identify Rad3ATR checkpoint kinase consensus phosphorylation sites and two SUMO interacting motifs (SIM) within a short N-terminal domain of Eme1 that is required for cell survival in absence of Rqh1BLM. We show that direct phosphorylation of Eme1 by Rad3ATR is essential for catalytic stimulation of Mus81-Eme1. Chk1-mediated phosphorylation also contributes to the stimulation of Mus81-Eme1 when combined with phosphorylation of Eme1 by Rad3ATR. Both Rad3ATR- and Chk1-mediated phosphorylation of Eme1 as well as the SIMs are critical for cell fitness in absence of Rqh1BLM and abrogating bimodal phosphorylation of Eme1 along with mutating the SIMs is incompatible with rqh1Δ cell viability. Our findings unravel an elaborate regulatory network that relies on the poorly structured N-terminal domain of Eme1 and which is essential for the vital functions Mus81-Eme1 fulfills in absence of Rqh1BLM. Structure-Specific Endonucleases (SSEs) are DNA cutting enzymes that process structures that form during DNA replication, recombination, repair and transcription. Their activities need to be tightly controlled to avoid that unscheduled DNA cutting drives genome instability. The fission yeast SSE Mus81-Eme1 specialized in the processing of DNA structures that link chromosomes, undergoes timely hyperactivation just before chromosome segregation. This involves cell cycle-driven phosphorylation of Eme1, which primes the protein for further phosphorylation by the DNA damage checkpoint. Here we discover that Eme1 is phosphorylated by the DNA damage sensor kinase Rad3ATR and demonstrate that this is essential for the stimulation of Mus81-Eme1. Phosphorylation by the downstream effector Chk1 kinase is also required for full-fledged stimulation of Mus81-Eme1 but requires that Eme1 is also phosphorylated by Rad3ATR. In parallel, we show that Eme1 binds the small SUMO protein that modulates the functions/destiny of proteins to which it is attached. Interestingly, we provide evidence that these SUMO-binding properties contribute to the control of Mus81-Eme1 only in part through modulation of its activity. The importance of these different regulatory layers is underscored by the fact that together they are essential for cell viability in absence of the Rqh1BLM helicase, which is related to the BLM helicase defective in highly cancer prone Bloom syndrome patients.
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5
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Hua Z, Fang Q, Zhang D, Luo Z, Yuan C, Lin Z. Crystal structure of the human MUS81-EME2 complex. Structure 2022; 30:743-752.e3. [DOI: 10.1016/j.str.2022.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 01/27/2022] [Accepted: 02/16/2022] [Indexed: 10/18/2022]
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6
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Marie L, Symington LS. Mechanism for inverted-repeat recombination induced by a replication fork barrier. Nat Commun 2022; 13:32. [PMID: 35013185 PMCID: PMC8748988 DOI: 10.1038/s41467-021-27443-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/22/2021] [Indexed: 01/11/2023] Open
Abstract
Replication stress and abundant repetitive sequences have emerged as primary conditions underlying genomic instability in eukaryotes. To gain insight into the mechanism of recombination between repeated sequences in the context of replication stress, we used a prokaryotic Tus/Ter barrier designed to induce transient replication fork stalling near inverted repeats in the budding yeast genome. Our study reveals that the replication fork block stimulates a unique recombination pathway dependent on Rad51 strand invasion and Rad52-Rad59 strand annealing activities, Mph1/Rad5 fork remodelers, Mre11/Exo1/Dna2 resection machineries, Rad1-Rad10 nuclease and DNA polymerase δ. Furthermore, we show recombination at stalled replication forks is limited by the Srs2 helicase and Mus81-Mms4/Yen1 nucleases. Physical analysis of the replication-associated recombinants revealed that half are associated with an inversion of sequence between the repeats. Based on our extensive genetic characterization, we propose a model for recombination of closely linked repeats that can robustly generate chromosome rearrangements. Replication stress and abundant repetitive sequences have emerged as primary conditions underlying genomic instability in eukaryotes. Here the authors use a prokaryotic Tus/Ter barrier designed to induce transient replication fork stalling near inverted repeats in the budding yeast genome to support a model for recombination of closely linked repeats at stalled replication forks.
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Affiliation(s)
- Léa Marie
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, USA. .,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, 10032, USA.
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7
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Oh JM, Myung K. Crosstalk between different DNA repair pathways for DNA double strand break repairs. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 873:503438. [PMID: 35094810 DOI: 10.1016/j.mrgentox.2021.503438] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/09/2021] [Accepted: 12/14/2021] [Indexed: 11/28/2022]
Abstract
DNA double strand breaks (DSBs) are the most threatening type of DNA lesions and must be repaired properly in order to inhibit severe diseases and cell death. There are four major repair pathways for DSBs: non-homologous end joining (NHEJ), homologous recombination (HR), single strand annealing (SSA) and alternative end joining (alt-EJ). Cells choose repair pathway depending on the cell cycle phase and the length of 3' end of the DNA when DSBs are generated. Blunt and short regions of the 5' or 3' overhang DNA are repaired by NHEJ, which uses direct ligation or limited resection processing of the broken DNA end. In contrast, HR, SSA and alt-EJ use the resected DNA generated by the MRN (MRE11-RAD50-NBS1) complex and C-terminal binding protein interacting protein (CtIP) activated during the S and G2 phases. Here, we review recent findings on each repair pathway and the choice of repair mechanism and highlight the role of mismatch repair (MMR) protein in HR.
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Affiliation(s)
- Jung-Min Oh
- Department of Oral Biochemistry, Dental and Life Science Institute, School of Dentistry, Pusan National University, Yangsan 50612, Republic of Korea.
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea; Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
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8
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Carreira R, Aguado FJ, Hurtado-Nieves V, Blanco MG. Canonical and novel non-canonical activities of the Holliday junction resolvase Yen1. Nucleic Acids Res 2021; 50:259-280. [PMID: 34928393 PMCID: PMC8754655 DOI: 10.1093/nar/gkab1225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/12/2021] [Accepted: 12/01/2021] [Indexed: 11/14/2022] Open
Abstract
Yen1 and GEN1 are members of the Rad2/XPG family of nucleases that were identified as the first canonical nuclear Holliday junction (HJ) resolvases in budding yeast and humans due to their ability to introduce two symmetric, coordinated incisions on opposite strands of the HJ, yielding nicked DNA products that could be readily ligated. While GEN1 has been extensively characterized in vitro, much less is known about the biochemistry of Yen1. Here, we have performed the first in-depth characterization of purified Yen1. We confirmed that Yen1 resembles GEN1 in many aspects, including range of substrates targeted, position of most incisions they produce or the increase in the first incision rate by assembly of a dimer on a HJ, despite minor differences. However, we demonstrate that Yen1 is endowed with additional nuclease activities, like a nick-specific 5′-3′ exonuclease or HJ arm-chopping that could apparently blur its classification as a canonical HJ resolvase. Despite this, we show that Yen1 fulfils the requirements of a canonical HJ resolvase and hypothesize that its wider array of nuclease activities might contribute to its function in the removal of persistent recombination or replication intermediates.
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Affiliation(s)
- Raquel Carreira
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
| | - F Javier Aguado
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
| | - Vanesa Hurtado-Nieves
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
| | - Miguel G Blanco
- Department of Biochemistry and Molecular Biology, CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), Santiago de Compostela, A Coruña 15782, Spain
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9
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Misova I, Pitelova A, Budis J, Gazdarica J, Sedlackova T, Jordakova A, Benko Z, Smondrkova M, Mayerova N, Pichlerova K, Strieskova L, Prevorovsky M, Gregan J, Cipak L, Szemes T, Polakova SB. Repression of a large number of genes requires interplay between homologous recombination and HIRA. Nucleic Acids Res 2021; 49:1914-1934. [PMID: 33511417 PMCID: PMC7913671 DOI: 10.1093/nar/gkab027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 12/13/2022] Open
Abstract
During homologous recombination, Dbl2 protein is required for localisation of Fbh1, an F-box helicase that efficiently dismantles Rad51-DNA filaments. RNA-seq analysis of dbl2Δ transcriptome showed that the dbl2 deletion results in upregulation of more than 500 loci in Schizosaccharomyces pombe. Compared with the loci with no change in expression, the misregulated loci in dbl2Δ are closer to long terminal and long tandem repeats. Furthermore, the misregulated loci overlap with antisense transcripts, retrotransposons, meiotic genes and genes located in subtelomeric regions. A comparison of the expression profiles revealed that Dbl2 represses the same type of genes as the HIRA histone chaperone complex. Although dbl2 deletion does not alleviate centromeric or telomeric silencing, it suppresses the silencing defect at the outer centromere caused by deletion of hip1 and slm9 genes encoding subunits of the HIRA complex. Moreover, our analyses revealed that cells lacking dbl2 show a slight increase of nucleosomes at transcription start sites and increased levels of methylated histone H3 (H3K9me2) at centromeres, subtelomeres, rDNA regions and long terminal repeats. Finally, we show that other proteins involved in homologous recombination, such as Fbh1, Rad51, Mus81 and Rad54, participate in the same gene repression pathway.
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Affiliation(s)
- Ivana Misova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Alexandra Pitelova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Jaroslav Budis
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
| | - Juraj Gazdarica
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Tatiana Sedlackova
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
| | - Anna Jordakova
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Praha 2, Czechia
| | - Zsigmond Benko
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
- Department of Molecular Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, H-4010 Debrecen, Hungary
| | - Maria Smondrkova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Nina Mayerova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Karoline Pichlerova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
| | - Lucia Strieskova
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
| | - Martin Prevorovsky
- Department of Cell Biology, Faculty of Science, Charles University, 128 00 Praha 2, Czechia
| | - Juraj Gregan
- Advanced Microscopy Facility, VBCF and Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Lubos Cipak
- Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, 845 05 Bratislava, Slovakia
| | - Tomas Szemes
- Comenius University Science Park, 841 04 Bratislava, Slovakia
- Geneton Ltd., 841 04 Bratislava, Slovakia
- Slovak Centre of Scientific and Technical Information, 811 04 Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
| | - Silvia Bagelova Polakova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, 840 05 Bratislava, Slovakia
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 841 04 Bratislava, Slovakia
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10
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Checkpoint functions of RecQ helicases at perturbed DNA replication fork. Curr Genet 2021; 67:369-382. [PMID: 33427950 DOI: 10.1007/s00294-020-01147-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/07/2020] [Accepted: 12/12/2020] [Indexed: 01/17/2023]
Abstract
DNA replication checkpoint is a cell signaling pathway that is activated in response to perturbed replication. Although it is crucial for maintaining genomic integrity and cell survival, the exact mechanism of the checkpoint signaling remains to be understood. Emerging evidence has shown that RecQ helicases, a large family of helicases that are conserved from bacteria to yeasts and humans, contribute to the replication checkpoint as sensors, adaptors, or regulation targets. Here, we highlight the multiple functions of RecQ helicases in the replication checkpoint in four model organisms and present additional evidence that fission yeast RecQ helicase Rqh1 may participate in the replication checkpoint as a sensor.
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11
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Al-Natour Z, Chalissery J, Hassan AH. Fun30 chromatin remodeler helps in dealing with torsional stress and camptothecin-induced DNA damage. Yeast 2020; 38:170-182. [PMID: 33141948 DOI: 10.1002/yea.3534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 10/04/2020] [Accepted: 10/26/2020] [Indexed: 12/19/2022] Open
Abstract
Fun30 is an ATP-dependent chromatin remodeler in budding yeast that is involved in cellular processes important for maintaining genomic stability such as gene silencing and DNA damage repair. Cells lacking Fun30 are moderately sensitive to the topoisomerase inhibitor camptothecin and exhibit a delay in cell cycle progression in the presence of camptothecin. Here, we show that Fun30 is required to cope with torsional stress in the absence of Top1. Moreover, we show through genetic studies that Fun30 acts in a parallel pathway to Mus81 endonuclease but is epistatic to Tdp1 phosphodiesterase and Rad1 endonuclease in the repair of camptothecin-induced DNA damage. More importantly, we show that DNA damage sensitivity of Fun30 deficient cells is enhanced in the absence of RNase H enzymes that remove RNA:DNA hybrids. We believe that chromatin remodeling by Fun30 may be important in dealing with torsional stress and camptothecin-induced DNA damage.
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Affiliation(s)
- Zeina Al-Natour
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Jisha Chalissery
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ahmed H Hassan
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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12
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Mus81-Mms4 endonuclease is an Esc2-STUbL-Cullin8 mitotic substrate impacting on genome integrity. Nat Commun 2020; 11:5746. [PMID: 33184279 PMCID: PMC7665200 DOI: 10.1038/s41467-020-19503-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 10/15/2020] [Indexed: 12/21/2022] Open
Abstract
The Mus81-Mms4 nuclease is activated in G2/M via Mms4 phosphorylation to allow resolution of persistent recombination structures. However, the fate of the activated phosphorylated Mms4 remains unknown. Here we find that Mms4 is engaged by (poly)SUMOylation and ubiquitylation and targeted for proteasome degradation, a process linked to the previously described Mms4 phosphorylation cycle. Mms4 is a mitotic substrate for the SUMO-Targeted Ubiquitin ligase Slx5/8, the SUMO-like domain-containing protein Esc2, and the Mms1-Cul8 ubiquitin ligase. In the absence of these activities, phosphorylated Mms4 accumulates on chromatin in an active state in the next G1, subsequently causing abnormal processing of replication-associated recombination intermediates and delaying the activation of the DNA damage checkpoint. Mus81-Mms4 mutants that stabilize phosphorylated Mms4 have similar detrimental effects on genome integrity. Overall, our findings highlight a replication protection function for Esc2-STUbL-Cul8 and emphasize the importance for genome stability of resetting phosphorylated Mms4 from one cycle to another. Mus81-Mms4 endonuclease is critical for processing various DNA recombination structures. Here the authors uncover a regulatory mechanism of the endonuclease via posttranslational modifications involving SUMOylation and ubiquitylation that impact on genome integrity.
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13
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Phung HTT, Tran DH, Nguyen TX. The cruciform DNA-binding protein Crp1 stimulates the endonuclease activity of Mus81-Mms4 in Saccharomyces cerevisiae. FEBS Lett 2020; 594:4320-4337. [PMID: 32936932 DOI: 10.1002/1873-3468.13931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/03/2020] [Accepted: 09/06/2020] [Indexed: 11/07/2022]
Abstract
The Saccharomyces cerevisiae Mus81-Mms4 complex is a highly conserved DNA structure-specific endonuclease that plays essential roles in the processing of recombination intermediates that arise during the repair of stalled replication forks and double-stranded breaks. To identify novel factors functioning conjointly with Mus81-Mms4, we performed a biochemical screen and found that Crp1, a cruciform DNA-recognizing protein that specifically binds to DNA four-way junction structures, could stimulate the Mus81-Mms4 endonuclease. The specific protein interaction between Mus81-Mms4 and Crp1 was responsible for the stimulation observed. Multicopy expression of Crp1 could partially rescue the sensitivity to DNA-damaging agents of the sgs1∆mus81∆21-24N mutant. Our results provide insight into the functional role and interaction of Crp1 with other proteins involved in DNA repair.
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Affiliation(s)
- Huong Thi Thu Phung
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
| | - Diem Hong Tran
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
| | - Ta Xuan Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
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14
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Saccharomyces cerevisiae Mus81-Mms4 prevents accelerated senescence in telomerase-deficient cells. PLoS Genet 2020; 16:e1008816. [PMID: 32469862 PMCID: PMC7286520 DOI: 10.1371/journal.pgen.1008816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 06/10/2020] [Accepted: 04/30/2020] [Indexed: 01/31/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) in human cells is a conserved process that is often activated in telomerase-deficient human cancers. This process exploits components of the recombination machinery to extend telomere ends, thus allowing for increased proliferative potential. Human MUS81 (Mus81 in Saccharomyces cerevisiae) is the catalytic subunit of structure-selective endonucleases involved in recombination and has been implicated in the ALT mechanism. However, it is unclear whether MUS81 activity at the telomere is specific to ALT cells or if it is required for more general aspects of telomere stability. In this study, we use S. cerevisiae to evaluate the contribution of the conserved Mus81-Mms4 endonuclease in telomerase-deficient yeast cells that maintain their telomeres by mechanisms akin to human ALT. Similar to human cells, we find that yeast Mus81 readily localizes to telomeres and its activity is important for viability after initial loss of telomerase. Interestingly, our analysis reveals that yeast Mus81 is not required for the survival of cells undergoing recombination-mediated telomere lengthening, i.e. for ALT itself. Rather we infer from genetic analysis that Mus81-Mms4 facilitates telomere replication during times of telomere instability. Furthermore, combining mus81 mutants with mutants of a yeast telomere replication factor, Rrm3, reveals that the two proteins function in parallel to promote normal growth during times of telomere stress. Combined with previous reports, our data can be interpreted in a consistent model in which both yeast and human MUS81-dependent nucleases participate in the recovery of stalled replication forks within telomeric DNA. Furthermore, this process becomes crucial under conditions of additional replication stress, such as telomere replication in telomerase-deficient cells. Cancer cell divisions require active chromosome lengthening through extension of their highly repetitive ends, called telomeres. This process is accomplished through two main mechanisms: the activity of an RNA-protein complex, telomerase, or through a telomerase-independent process termed alternative lengthening of telomeres (ALT). Human MUS81, the catalytic subunit of a set of structure-selective endonucleases, was found to be essential in human cells undergoing ALT and proposed to be directly involved in telomere lengthening. Using telomerase-deficient Saccharomyces cerevisiae cells as a model for ALT, we tested the hypothesis that Mus81-Mms4, the budding yeast homolog of human MUS81-dependent nucleases, is essential for telomere lengthening as proposed for human cells. Using genetic and molecular assays we confirm that Mus81-Mms4 is involved in telomere metabolism in yeast. However, to our surprise, we find that Mus81-Mms4 is not directly involved in recombination-based mechanisms of telomere lengthening. Rather it appears that Mus81-Mms4 is involved in resolving replication stress at telomeres, which is augmented in cells undergoing telomere instability. This model is consistent with observations in mammalian cells and suggest that cells undergoing telomere shortening experience replication stress at telomeres.
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15
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Giovannini S, Weller MC, Hanzlíková H, Shiota T, Takeda S, Jiricny J. ATAD5 deficiency alters DNA damage metabolism and sensitizes cells to PARP inhibition. Nucleic Acids Res 2020; 48:4928-4939. [PMID: 32297953 PMCID: PMC7229844 DOI: 10.1093/nar/gkaa255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/31/2020] [Accepted: 04/04/2020] [Indexed: 01/05/2023] Open
Abstract
Replication factor C (RFC), a heteropentamer of RFC1-5, loads PCNA onto DNA during replication and repair. Once DNA synthesis has ceased, PCNA must be unloaded. Recent findings assign the uloader role primarily to an RFC-like (RLC) complex, in which the largest RFC subunit, RFC1, has been replaced with ATAD5 (ELG1 in Saccharomyces cerevisiae). ATAD5-RLC appears to be indispensable, given that Atad5 knock-out leads to embryonic lethality. In order to learn how the retention of PCNA on DNA might interfere with normal DNA metabolism, we studied the response of ATAD5-depleted cells to several genotoxic agents. We show that ATAD5 deficiency leads to hypersensitivity to methyl methanesulphonate (MMS), camptothecin (CPT) and mitomycin C (MMC), agents that hinder the progression of replication forks. We further show that ATAD5-depleted cells are sensitive to poly(ADP)ribose polymerase (PARP) inhibitors and that the processing of spontaneous oxidative DNA damage contributes towards this sensitivity. We posit that PCNA molecules trapped on DNA interfere with the correct metabolism of arrested replication forks, phenotype reminiscent of defective homologous recombination (HR). As Atad5 heterozygous mice are cancer-prone and as ATAD5 mutations have been identified in breast and endometrial cancers, our finding may open a path towards the therapy of these tumours.
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Affiliation(s)
- Sara Giovannini
- Institute of Molecular Life Sciences of the University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Molecular Cancer Research of the University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Biochemistry of the Swiss Federal Institute of Technology, Otto-Stern-Weg 3, 8093 Zurich, Switzerland
| | - Marie-Christine Weller
- Institute of Molecular Cancer Research of the University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Hana Hanzlíková
- Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Sciences, 142-20 Prague 4, Czech Republic
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Tetsuya Shiota
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, 606-8501 Kyoto, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, 606-8501 Kyoto, Japan
| | - Josef Jiricny
- Institute of Molecular Life Sciences of the University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Molecular Cancer Research of the University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Biochemistry of the Swiss Federal Institute of Technology, Otto-Stern-Weg 3, 8093 Zurich, Switzerland
- To whom correspondence should be addressed. Tel: +41 44 633 6260;
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16
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Bittmann J, Grigaitis R, Galanti L, Amarell S, Wilfling F, Matos J, Pfander B. An advanced cell cycle tag toolbox reveals principles underlying temporal control of structure-selective nucleases. eLife 2020; 9:e52459. [PMID: 32352375 PMCID: PMC7220381 DOI: 10.7554/elife.52459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 04/29/2020] [Indexed: 12/26/2022] Open
Abstract
Cell cycle tags allow to restrict target protein expression to specific cell cycle phases. Here, we present an advanced toolbox of cell cycle tag constructs in budding yeast with defined and compatible peak expression that allow comparison of protein functionality at different cell cycle phases. We apply this technology to the question of how and when Mus81-Mms4 and Yen1 nucleases act on DNA replication or recombination structures. Restriction of Mus81-Mms4 to M phase but not S phase allows a wildtype response to various forms of replication perturbation and DNA damage in S phase, suggesting it acts as a post-replicative resolvase. Moreover, we use cell cycle tags to reinstall cell cycle control to a deregulated version of Yen1, showing that its premature activation interferes with the response to perturbed replication. Curbing resolvase activity and establishing a hierarchy of resolution mechanisms are therefore the principal reasons underlying resolvase cell cycle regulation.
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Affiliation(s)
- Julia Bittmann
- Max Planck Institute of Biochemistry, DNA Replication and Genome IntegrityMartinsriedGermany
| | - Rokas Grigaitis
- Institute of Biochemistry, Eidgenössische Technische Hochschule, ZürichZürichSwitzerland
| | - Lorenzo Galanti
- Max Planck Institute of Biochemistry, DNA Replication and Genome IntegrityMartinsriedGermany
| | - Silas Amarell
- Max Planck Institute of Biochemistry, DNA Replication and Genome IntegrityMartinsriedGermany
| | - Florian Wilfling
- Max Planck Institute of Biochemistry, Molecular Cell BiologyMartinsriedGermany
| | - Joao Matos
- Institute of Biochemistry, Eidgenössische Technische Hochschule, ZürichZürichSwitzerland
| | - Boris Pfander
- Max Planck Institute of Biochemistry, DNA Replication and Genome IntegrityMartinsriedGermany
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17
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Brosh RM, Matson SW. History of DNA Helicases. Genes (Basel) 2020; 11:genes11030255. [PMID: 32120966 PMCID: PMC7140857 DOI: 10.3390/genes11030255] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/13/2022] Open
Abstract
Since the discovery of the DNA double helix, there has been a fascination in understanding the molecular mechanisms and cellular processes that account for: (i) the transmission of genetic information from one generation to the next and (ii) the remarkable stability of the genome. Nucleic acid biologists have endeavored to unravel the mysteries of DNA not only to understand the processes of DNA replication, repair, recombination, and transcription but to also characterize the underlying basis of genetic diseases characterized by chromosomal instability. Perhaps unexpectedly at first, DNA helicases have arisen as a key class of enzymes to study in this latter capacity. From the first discovery of ATP-dependent DNA unwinding enzymes in the mid 1970's to the burgeoning of helicase-dependent pathways found to be prevalent in all kingdoms of life, the story of scientific discovery in helicase research is rich and informative. Over four decades after their discovery, we take this opportunity to provide a history of DNA helicases. No doubt, many chapters are left to be written. Nonetheless, at this juncture we are privileged to share our perspective on the DNA helicase field - where it has been, its current state, and where it is headed.
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Affiliation(s)
- Robert M. Brosh
- Section on DNA Helicases, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
- Correspondence: (R.M.B.J.); (S.W.M.); Tel.: +1-410-558-8578 (R.M.B.J.); +1-919-962-0005 (S.W.M.)
| | - Steven W. Matson
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: (R.M.B.J.); (S.W.M.); Tel.: +1-410-558-8578 (R.M.B.J.); +1-919-962-0005 (S.W.M.)
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18
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Gupta SV, Schmidt KH. Maintenance of Yeast Genome Integrity by RecQ Family DNA Helicases. Genes (Basel) 2020; 11:E205. [PMID: 32085395 PMCID: PMC7074392 DOI: 10.3390/genes11020205] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 12/28/2022] Open
Abstract
With roles in DNA repair, recombination, replication and transcription, members of the RecQ DNA helicase family maintain genome integrity from bacteria to mammals. Mutations in human RecQ helicases BLM, WRN and RecQL4 cause incurable disorders characterized by genome instability, increased cancer predisposition and premature adult-onset aging. Yeast cells lacking the RecQ helicase Sgs1 share many of the cellular defects of human cells lacking BLM, including hypersensitivity to DNA damaging agents and replication stress, shortened lifespan, genome instability and mitotic hyper-recombination, making them invaluable model systems for elucidating eukaryotic RecQ helicase function. Yeast and human RecQ helicases have common DNA substrates and domain structures and share similar physical interaction partners. Here, we review the major cellular functions of the yeast RecQ helicases Sgs1 of Saccharomyces cerevisiae and Rqh1 of Schizosaccharomyces pombe and provide an outlook on some of the outstanding questions in the field.
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Affiliation(s)
- Sonia Vidushi Gupta
- Department of Cell Biology, Microbiology and Molecular Biology, University of South, Florida, Tampa, FL 33620, USA;
| | - Kristina Hildegard Schmidt
- Department of Cell Biology, Microbiology and Molecular Biology, University of South, Florida, Tampa, FL 33620, USA;
- Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research, Institute, Tampa, FL 33612, USA
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19
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Resolvases, Dissolvases, and Helicases in Homologous Recombination: Clearing the Road for Chromosome Segregation. Genes (Basel) 2020; 11:genes11010071. [PMID: 31936378 PMCID: PMC7017083 DOI: 10.3390/genes11010071] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/29/2019] [Accepted: 01/01/2020] [Indexed: 12/13/2022] Open
Abstract
The execution of recombinational pathways during the repair of certain DNA lesions or in the meiotic program is associated to the formation of joint molecules that physically hold chromosomes together. These structures must be disengaged prior to the onset of chromosome segregation. Failure in the resolution of these linkages can lead to chromosome breakage and nondisjunction events that can alter the normal distribution of the genomic material to the progeny. To avoid this situation, cells have developed an arsenal of molecular complexes involving helicases, resolvases, and dissolvases that recognize and eliminate chromosome links. The correct orchestration of these enzymes promotes the timely removal of chromosomal connections ensuring the efficient segregation of the genome during cell division. In this review, we focus on the role of different DNA processing enzymes that collaborate in removing the linkages generated during the activation of the homologous recombination machinery as a consequence of the appearance of DNA breaks during the mitotic and meiotic programs. We will also discuss about the temporal regulation of these factors along the cell cycle, the consequences of their loss of function, and their specific role in the removal of chromosomal links to ensure the accurate segregation of the genomic material during cell division.
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20
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Santos SM, Hartman JL. A yeast phenomic model for the influence of Warburg metabolism on genetic buffering of doxorubicin. Cancer Metab 2019; 7:9. [PMID: 31660150 PMCID: PMC6806529 DOI: 10.1186/s40170-019-0201-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 09/03/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The influence of the Warburg phenomenon on chemotherapy response is unknown. Saccharomyces cerevisiae mimics the Warburg effect, repressing respiration in the presence of adequate glucose. Yeast phenomic experiments were conducted to assess potential influences of Warburg metabolism on gene-drug interaction underlying the cellular response to doxorubicin. Homologous genes from yeast phenomic and cancer pharmacogenomics data were analyzed to infer evolutionary conservation of gene-drug interaction and predict therapeutic relevance. METHODS Cell proliferation phenotypes (CPPs) of the yeast gene knockout/knockdown library were measured by quantitative high-throughput cell array phenotyping (Q-HTCP), treating with escalating doxorubicin concentrations under conditions of respiratory or glycolytic metabolism. Doxorubicin-gene interaction was quantified by departure of CPPs observed for the doxorubicin-treated mutant strain from that expected based on an interaction model. Recursive expectation-maximization clustering (REMc) and Gene Ontology (GO)-based analyses of interactions identified functional biological modules that differentially buffer or promote doxorubicin cytotoxicity with respect to Warburg metabolism. Yeast phenomic and cancer pharmacogenomics data were integrated to predict differential gene expression causally influencing doxorubicin anti-tumor efficacy. RESULTS Yeast compromised for genes functioning in chromatin organization, and several other cellular processes are more resistant to doxorubicin under glycolytic conditions. Thus, the Warburg transition appears to alleviate requirements for cellular functions that buffer doxorubicin cytotoxicity in a respiratory context. We analyzed human homologs of yeast genes exhibiting gene-doxorubicin interaction in cancer pharmacogenomics data to predict causality for differential gene expression associated with doxorubicin cytotoxicity in cancer cells. This analysis suggested conserved cellular responses to doxorubicin due to influences of homologous recombination, sphingolipid homeostasis, telomere tethering at nuclear periphery, actin cortical patch localization, and other gene functions. CONCLUSIONS Warburg status alters the genetic network required for yeast to buffer doxorubicin toxicity. Integration of yeast phenomic and cancer pharmacogenomics data suggests evolutionary conservation of gene-drug interaction networks and provides a new experimental approach to model their influence on chemotherapy response. Thus, yeast phenomic models could aid the development of precision oncology algorithms to predict efficacious cytotoxic drugs for cancer, based on genetic and metabolic profiles of individual tumors.
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Affiliation(s)
- Sean M. Santos
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL USA
| | - John L. Hartman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL USA
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21
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Falquet B, Rass U. Structure-Specific Endonucleases and the Resolution of Chromosome Underreplication. Genes (Basel) 2019; 10:E232. [PMID: 30893921 PMCID: PMC6470701 DOI: 10.3390/genes10030232] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 12/11/2022] Open
Abstract
Complete genome duplication in every cell cycle is fundamental for genome stability and cell survival. However, chromosome replication is frequently challenged by obstacles that impede DNA replication fork (RF) progression, which subsequently causes replication stress (RS). Cells have evolved pathways of RF protection and restart that mitigate the consequences of RS and promote the completion of DNA synthesis prior to mitotic chromosome segregation. If there is entry into mitosis with underreplicated chromosomes, this results in sister-chromatid entanglements, chromosome breakage and rearrangements and aneuploidy in daughter cells. Here, we focus on the resolution of persistent replication intermediates by the structure-specific endonucleases (SSEs) MUS81, SLX1-SLX4 and GEN1. Their actions and a recently discovered pathway of mitotic DNA repair synthesis have emerged as important facilitators of replication completion and sister chromatid detachment in mitosis. As RS is induced by oncogene activation and is a common feature of cancer cells, any advances in our understanding of the molecular mechanisms related to chromosome underreplication have important biomedical implications.
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Affiliation(s)
- Benoît Falquet
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
- Faculty of Natural Sciences, University of Basel, Petersplatz 10, CH-4003 Basel, Switzerland.
| | - Ulrich Rass
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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22
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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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23
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Dorn A, Röhrig S, Papp K, Schröpfer S, Hartung F, Knoll A, Puchta H. The topoisomerase 3α zinc-finger domain T1 of Arabidopsis thaliana is required for targeting the enzyme activity to Holliday junction-like DNA repair intermediates. PLoS Genet 2018; 14:e1007674. [PMID: 30222730 PMCID: PMC6160208 DOI: 10.1371/journal.pgen.1007674] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/27/2018] [Accepted: 08/31/2018] [Indexed: 12/18/2022] Open
Abstract
Topoisomerase 3α, a class I topoisomerase, consists of a TOPRIM domain, an active centre and a variable number of zinc-finger domains (ZFDs) at the C-terminus, in multicellular organisms. Whereas the functions of the TOPRIM domain and the active centre are known, the specific role of the ZFDs is still obscure. In contrast to mammals where a knockout of TOP3α leads to lethality, we found that CRISPR/Cas induced mutants in Arabidopsis are viable but show growth retardation and meiotic defects, which can be reversed by the expression of the complete protein. However, complementation with AtTOP3α missing either the TOPRIM-domain or carrying a mutation of the catalytic tyrosine of the active centre leads to embryo lethality. Surprisingly, this phenotype can be overcome by the simultaneous removal of the ZFDs from the protein. In combination with a mutation of the nuclease AtMUS81, the TOP3α knockout proved to be also embryo lethal. Here, expression of TOP3α without ZFDs, and in particular without the conserved ZFD T1, leads to only a partly complementation in root growth-in contrast to the complete protein, that restores root length to mus81-1 mutant level. Expressing the E. coli resolvase RusA in this background, which is able to process Holliday junction (HJ)-like recombination intermediates, we could rescue this root growth defect. Considering all these results, we conclude that the ZFD T1 is specifically required for targeting the topoisomerase activity to HJ like recombination intermediates to enable their processing. In the case of an inactivated enzyme, this leads to cell death due to the masking of these intermediates, hindering their resolution by MUS81.
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Affiliation(s)
- Annika Dorn
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sarah Röhrig
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Kristin Papp
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Susan Schröpfer
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Frank Hartung
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alexander Knoll
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute, Molecular Biology and Biochemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
- * E-mail:
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24
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Phung HTT, Nguyen HLH, Vo ST, Nguyen DH, Le MV. Saccharomyces cerevisiae Mus81-Mms4 and Rad52 can cooperate in the resolution of recombination intermediates. Yeast 2018; 35:543-553. [PMID: 29738624 DOI: 10.1002/yea.3320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 02/26/2018] [Accepted: 04/23/2018] [Indexed: 11/06/2022] Open
Abstract
Mus81 is a well-conserved DNA structure-specific endonuclease which belongs to the XPF/Rad1 family of proteins that are involved in DNA nucleotide excision repair. Mus81 forms a heterodimer with a non-catalytic subunit, Mms4, in Saccharomyces cerevisiae (Eme1/EME1 in Schizosaccharomyces pombe and mammals). Recent evidence shows that Mus81 functions redundantly with Sgs1, a member of the ubiquitous RecQ family of DNA helicases, to process toxic recombinant intermediates. In budding yeast, homologous recombination is regulated by the Rad52 epistasis group of proteins, including Rad52, which stimulates the main steps of DNA sequence-homology searching. Mus81 was proven to act in the Rad52-dependent pathway. Here, we demonstrate that Rad52 and Mus81-Mms4 possesses a functional interaction; the presence of Rad52 significantly enhances the endonuclease activity of Mus81-Mms4 on a broad range of its preferred synthetic substrates. Furthermore, this functional interaction is demonstrated to be species specific. We fragmented Rad52 and found that the N-terminal fragment from the 86th to 169th amino acid residue, which belongs to DNA-binding and self-association domains, can stimulate Mus81-Mms4 endonuclease. These results strongly support the notion that Rad52 and Mus81-Mms4 collaborate and work jointly in processing of homologous recombination intermediates.
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Affiliation(s)
- Huong Thi Thu Phung
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ward 13, District 4, Ho Chi Minh city, 700000, Vietnam
| | - Hoa Luong Hieu Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ward 13, District 4, Ho Chi Minh city, 700000, Vietnam
| | - Sang Thanh Vo
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ward 13, District 4, Ho Chi Minh city, 700000, Vietnam
| | - Dung Hoang Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ward 13, District 4, Ho Chi Minh city, 700000, Vietnam
| | - Minh Van Le
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, Ward 13, District 4, Ho Chi Minh city, 700000, Vietnam
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25
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Saugar I, Jiménez-Martín A, Tercero JA. Subnuclear Relocalization of Structure-Specific Endonucleases in Response to DNA Damage. Cell Rep 2018; 20:1553-1562. [PMID: 28813668 DOI: 10.1016/j.celrep.2017.07.059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 05/09/2017] [Accepted: 07/20/2017] [Indexed: 12/25/2022] Open
Abstract
Structure-specific endonucleases contribute to the maintenance of genome integrity by cleaving DNA intermediates that need to be resolved for faithful DNA repair, replication, or recombination. Despite advances in the understanding of their function and regulation, it is less clear how these proteins respond to genotoxic stress. Here, we show that the structure-specific endonuclease Mus81-Mms4/EME1 relocalizes to subnuclear foci following DNA damage and colocalizes with the endonucleases Rad1-Rad10 (XPF-ERCC1) and Slx1-Slx4. Recruitment takes place into a class of stress foci defined by Cmr1/WDR76, a protein involved in preserving genome stability, and depends on the E2-ubiquitin-conjugating enzyme Rad6 and the E3-ubiquitin ligase Bre1. Foci dynamics show that, in the presence of DNA intermediates that need resolution by Mus81-Mms4, Mus81 foci persist until this endonuclease is activated by Mms4 phosphorylation. Our data suggest that subnuclear relocalization is relevant for the function of Mus81-Mms4 and, probably, of the endonucleases that colocalize with it.
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Affiliation(s)
- Irene Saugar
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Cantoblanco, 28049 Madrid, Spain
| | | | - José Antonio Tercero
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Cantoblanco, 28049 Madrid, Spain.
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26
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Phung HTT, Nguyen HLH, Nguyen DH. The possible function of Flp1 in homologous recombination repair in Saccharomyces cerevisiae. AIMS GENETICS 2018; 5:161-176. [PMID: 31435519 PMCID: PMC6698574 DOI: 10.3934/genet.2018.2.161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 03/18/2018] [Indexed: 11/18/2022]
Abstract
Saccharomyces cerevisiae Mus81 is a structure-selective endonuclease which constitutes an alternative pathway in parallel with the helicase-topoisomerase Sgs1-Top3-Rmi1 complex to resolve a number of DNA intermediates during DNA replication, repair, and homologous recombination. Previously, it was showed that the N-terminal region of Mus81 was required for its in vivo function in a redundant manner with Sgs1; mus81Δ120N mutant that lacks the first 120 amino acid residues at the N-terminus exhibited synthetic lethality in combination with the loss of SGS1. In this study, the physiologically important role of the N-terminal region of Mus81 in processing toxic intermediates was further investigated. We examined the cellular defect of sgs1Δmus81Δ100N cells and observed that although viable, the cells became very sensitive to DNA damaging agents. A single-copy suppressor screening to seek for a factor(s) that could rescue the drug sensitivity of sgs1Δmus81Δ100N cells was performed and revealed that Flp1, a site-specific recombinase 1 encoded on the 2-micron plasmid was a suppressor. Moreover, Flp1 overexpression could partially suppress the drug sensitivity of mus81Δ cells at 37 °C. Our findings suggest a possible function of Flp1 in coordination with Mus81 and Sgs1 to jointly resolve the branched-DNA structures generated in cells attempting to repair DNA damages.
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Affiliation(s)
- Huong Thi Thu Phung
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh city, Vietnam
| | | | - Dung Hoang Nguyen
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh city, Vietnam
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27
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Kojic M, Milisavljevic M, Holloman WK. Collaboration in the actions of Brh2 with resolving functions during DNA repair and replication stress in Ustilago maydis. DNA Repair (Amst) 2018; 63:47-55. [PMID: 29414053 DOI: 10.1016/j.dnarep.2018.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/18/2018] [Accepted: 01/29/2018] [Indexed: 11/17/2022]
Abstract
Cells maintain a small arsenal of resolving functions to process and eliminate complex DNA intermediates that result as a consequence of homologous recombination and distressed replication. Ordinarily the homologous recombination system serves as a high-fidelity mechanism to restore the integrity of a damaged genome, but in the absence of the appropriate resolving function it can turn DNA intermediates resulting from replication stress into pathological forms that are toxic to cells. Here we have investigated how the nucleases Mus81 and Gen1 and the helicase Blm contribute to survival after DNA damage or replication stress in Ustilago maydis cells with crippled yet homologous recombination-proficient forms of Brh2, the BRCA2 ortholog and primary Rad51 mediator. We found collaboration among the factors. Notable were three findings. First, the ability of Gen1 to rescue hydroxyurea sensitivity of dysfunctional Blm requires the absence of Mus81. Second, the response of mutants defective in Blm and Gen1 to hydroxyurea challenge is markedly similar suggesting cooperation of these factors in the same pathway. Third, the repair proficiency of Brh2 mutant variants deleted of its N-terminal DNA binding region requires not only Rad52 but also Gen1 and Mus81. We suggest these factors comprise a subpathway for channeling repair when Brh2 is compromised in its interplay with DNA.
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Affiliation(s)
- Milorad Kojic
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Mira Milisavljevic
- Laboratory for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Serbia
| | - William K Holloman
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA.
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Genetic Evidence for Roles of Yeast Mitotic Cyclins at Single-Stranded Gaps Created by DNA Replication. G3-GENES GENOMES GENETICS 2018; 8:737-752. [PMID: 29279302 PMCID: PMC5919743 DOI: 10.1534/g3.117.300537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Paused or stalled replication forks are major threats to genome integrity; unraveling the complex pathways that contribute to fork stability and restart is crucial. Experimentally, fork stalling is induced by growing the cells in presence of hydroxyurea (HU), which depletes the pool of deoxynucleotide triphosphates (dNTPs) and slows down replication progression in yeast. Here, I report an epistasis analysis, based on sensitivity to HU, between CLB2, the principal mitotic cyclin gene in Saccharomyces cerevisiae, and genes involved in fork stability and recombination. clb2Δ cells are not sensitive to HU, but the strong synergistic effect of clb2Δ with most genes tested indicates, unexpectedly, that CLB2 has an important role in DNA replication, in the stability and restart of stalled forks, and in pathways dependent on and independent of homologous recombination. Results indicate that CLB2 functions in parallel with the SGS1 helicase and EXO1 exonuclease to allow proper Rad51 recombination, but also regulates a combined Sgs1–Exo1 activity in a pathway dependent on Mec1 and Rad53 checkpoint protein kinases. The data argue that Mec1 regulates Clb2 to prevent a deleterious Sgs1–Exo1 activity at paused or stalled forks, whereas Rad53 checkpoint activation regulates Clb2 to allow a necessary Sgs1–Exo1 activity at stalled or collapsed forks. Altogether, this study indicates that Clb2 regulates the activity of numerous nucleases at single-stranded gaps created by DNA replication. A model is proposed for the function and regulation of Clb2 at stalled forks. These data provide new perspectives on the role of mitotic cyclins at the end of S phase.
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29
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Zhao X, Wei C, Li J, Xing P, Li J, Zheng S, Chen X. Cell cycle-dependent control of homologous recombination. Acta Biochim Biophys Sin (Shanghai) 2017; 49:655-668. [PMID: 28541389 DOI: 10.1093/abbs/gmx055] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Indexed: 01/29/2023] Open
Abstract
DNA double-strand breaks (DSBs) are among the most deleterious type of DNA lesions threatening genome integrity. Homologous recombination (HR) and non-homologous end joining (NHEJ) are two major pathways to repair DSBs. HR requires a homologous template to direct DNA repair, and is generally recognized as a high-fidelity pathway. In contrast, NHEJ directly seals broken ends, but the repair product is often accompanied by sequence alterations. The choice of repair pathways is strictly controlled by the cell cycle. The occurrence of HR is restricted to late S to G2 phases while NHEJ operates predominantly in G1 phase, although it can act throughout most of the cell cycle. Deregulation of repair pathway choice can result in genotoxic consequences associated with cancers. How the cell cycle regulates the choice of HR and NHEJ has been extensively studied in the past decade. In this review, we will focus on the current progresses on how HR is controlled by the cell cycle in both Saccharomyces cerevisiae and mammals. Particular attention will be given to how cyclin-dependent kinases modulate DSB end resection, DNA damage checkpoint signaling, repair and processing of recombination intermediates. In addition, we will discuss recent findings on how HR is repressed in G1 and M phases by the cell cycle.
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Affiliation(s)
- Xin Zhao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Chengwen Wei
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Jingjing Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Poyuan Xing
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Jingyao Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Sihao Zheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Xuefeng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences and the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
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Fujii N. Potential Strategies to Target Protein-Protein Interactions in the DNA Damage Response and Repair Pathways. J Med Chem 2017; 60:9932-9959. [PMID: 28654754 DOI: 10.1021/acs.jmedchem.7b00358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review article discusses some insights about generating novel mechanistic inhibitors of the DNA damage response and repair (DDR) pathways by focusing on protein-protein interactions (PPIs) of the key DDR components. General requirements for PPI strategies, such as selecting the target PPI site on the basis of its functionality, are discussed first. Next, on the basis of functional rationale and biochemical feasibility to identify a PPI inhibitor, 26 PPIs in DDR pathways (BER, MMR, NER, NHEJ, HR, TLS, and ICL repair) are specifically discussed for inhibitor discovery to benefit cancer therapies using a DNA-damaging agent.
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Affiliation(s)
- Naoaki Fujii
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital , 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
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31
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Abstract
DNA replication and homologous recombination involve the formation of branched DNA structures that physically link chromosomes. Such DNA-based connections, which arise during S-phase, are typically disengaged prior to entry into mitosis, in order to ensure proper chromosome segregation. Exceptions can, however, occur: replication stress, or elevated levels of DNA damage, may cause cells to enter mitosis with unfinished replication as well as carrying recombination intermediates, such as Holliday junctions. Hence, cells are equipped with pathways that recognize and process branched DNA structures, and evolved mechanisms to enhance their function when on the verge of undergoing cell division. One of these pathways utilizes the structure-selective endonuclease Mus81, which is thought to facilitate the resolution of replication and recombination intermediates. Mus81 function is known to be enhanced upon entry into M phase in budding yeast and human cells. Based on recent findings, we discuss here an updated model of Mus81 control during the cell cycle.
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Affiliation(s)
- Boris Pfander
- DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Joao Matos
- Institute of Biochemistry, HPM D6.5 - ETH Zürich, Zürich, Switzerland
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32
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Lindsay-Scott PJ, Gallagher PT. Synthesis of heterocycles from arylacetonitriles: Powerful tools for medicinal chemists. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.05.089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bellendir SP, Rognstad DJ, Morris LP, Zapotoczny G, Walton WG, Redinbo MR, Ramsden DA, Sekelsky J, Erie DA. Substrate preference of Gen endonucleases highlights the importance of branched structures as DNA damage repair intermediates. Nucleic Acids Res 2017; 45:5333-5348. [PMID: 28369583 PMCID: PMC5435919 DOI: 10.1093/nar/gkx214] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 02/16/2017] [Accepted: 03/21/2017] [Indexed: 11/20/2022] Open
Abstract
Human GEN1 and yeast Yen1 are endonucleases with the ability to cleave Holliday junctions (HJs), which are proposed intermediates in recombination. In vivo, GEN1 and Yen1 function secondarily to Mus81, which has weak activity on intact HJs. We show that the genetic relationship is reversed in Drosophila, with Gen mutants having more severe defects than mus81 mutants. In vitro, DmGen, like HsGEN1, efficiently cleaves HJs, 5΄ flaps, splayed arms, and replication fork structures. We find that the cleavage rates for 5΄ flaps are significantly higher than those for HJs for both DmGen and HsGEN1, even in vast excess of enzyme over substrate. Kinetic studies suggest that the difference in cleavage rates results from a slow, rate-limiting conformational change prior to HJ cleavage: formation of a productive dimer on the HJ. Despite the stark difference in vivo that Drosophila uses Gen over Mus81 and humans use MUS81 over GEN1, we find the in vitro activities of DmGen and HsGEN1 to be strikingly similar. These findings suggest that simpler branched structures may be more important substrates for Gen orthologs in vivo, and highlight the utility of using the Drosophila model system to further understand these enzymes.
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Affiliation(s)
| | | | - Lydia P. Morris
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
| | | | | | - Matthew R. Redinbo
- Department of Chemistry, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
| | - Dale A. Ramsden
- Curriculum in Genetics and Molecular Biology, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
- Department of Biochemistry and Biophysics, Chapel Hill, NC 27599, USA
| | - Jeff Sekelsky
- Curriculum in Genetics and Molecular Biology, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Dorothy A. Erie
- Department of Chemistry, Chapel Hill, NC 27599, USA
- Integrative Program for Biological and Genome Sciences, Chapel Hill, NC 27599, USA
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34
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Talhaoui I, Bernal M, Mazón G. The nucleolytic resolution of recombination intermediates in yeast mitotic cells. FEMS Yeast Res 2016; 16:fow065. [PMID: 27509904 DOI: 10.1093/femsyr/fow065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2016] [Indexed: 12/20/2022] Open
Abstract
In mitotic cells, the repair of double-strand breaks by homologous recombination (HR) is important for genome integrity. HR requires the orchestration of a subset of pathways for timely removal of joint-molecule intermediates that would otherwise prevent segregation of chromosomes in mitosis. The use of nucleases to resolve recombination intermediates is important for chromosome segregation, but is hazardous because crossovers can result in loss of heterozygosity or chromosome rearrangements. Unregulated use of the nucleases involved in the resolution of recombination intermediates could also be a risk during replication. The yeast models (Saccharomyces cerevisae and Schizosaccharomyces pombe) have proven effective in determining the major nucleases involved in the processing of such intermediates: Mus81-Mms4 and Yen1. Mus81-Mms4 and Yen1 are regulated by the cell cycle in a gradual activation during G2/M to keep the crossing-over risk low while ensuring proper removal of HJ intermediates.
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Affiliation(s)
- Ibtissam Talhaoui
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Manuel Bernal
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
| | - Gerard Mazón
- Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS) UMR 8200 Genetic Stability and Oncogenesis, Gustave Roussy, 114 rue Edouard Vaillant, 94805 Villejuif, France
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35
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Keyamura K, Arai K, Hishida T. Srs2 and Mus81-Mms4 Prevent Accumulation of Toxic Inter-Homolog Recombination Intermediates. PLoS Genet 2016; 12:e1006136. [PMID: 27390022 PMCID: PMC4936719 DOI: 10.1371/journal.pgen.1006136] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/31/2016] [Indexed: 11/18/2022] Open
Abstract
Homologous recombination is an evolutionally conserved mechanism that promotes genome stability through the faithful repair of double-strand breaks and single-strand gaps in DNA, and the recovery of stalled or collapsed replication forks. Saccharomyces cerevisiae ATP-dependent DNA helicase Srs2 (a member of the highly conserved UvrD family of helicases) has multiple roles in regulating homologous recombination. A mutation (srs2K41A) resulting in a helicase-dead mutant of Srs2 was found to be lethal in diploid, but not in haploid, cells. In diploid cells, Srs2K41A caused the accumulation of inter-homolog joint molecule intermediates, increased the levels of spontaneous Rad52 foci, and induced gross chromosomal rearrangements. Srs2K41A lethality and accumulation of joint molecules were suppressed by inactivating Rad51 or deleting the Rad51-interaction domain of Srs2, whereas phosphorylation and sumoylation of Srs2 and its interaction with sumoylated proliferating cell nuclear antigen (PCNA) were not required for lethality. The structure-specific complex of crossover junction endonucleases Mus81 and Mms4 was also required for viability of diploid, but not haploid, SRS2 deletion mutants (srs2Δ), and diploid srs2Δ mus81Δ mutants accumulated joint molecule intermediates. Our data suggest that Srs2 and Mus81–Mms4 have critical roles in preventing the formation of (or in resolving) toxic inter-homolog joint molecules, which could otherwise interfere with chromosome segregation and lead to genetic instability. Homologous recombination (HR) is a DNA-repair mechanism that is generally considered error free because it uses an intact sister chromatid as a template. However, in diploid cells, HR can also occur between homologous chromosomes, which can lead to genomic instability through loss of heterozygosity. This alteration is often detected in genetic disorders and cancer, suggesting that tight control of this process is required to ensure genome stability. Yeast Srs2, conserved from bacteria to humans, plays multiple roles in the regulation of HR. We show here that a helicase-dead mutant of Srs2, srs2K41A, is lethal in diploid cells but not in haploid cells. Expression of Srs2K41A in diploid cells causes inter-homolog joint molecule intermediates to accumulate, and leads to gross chromosomal rearrangements. Moreover, srs2Δ mus81Δ double mutants have a severe diploid-specific growth defect with accumulation of inter-homolog joint molecules. These data demonstrate that Srs2 and Mus81-Mms4 participate in essential pathways preventing accumulation of inter-homolog recombination intermediates, thereby reducing the risk of genome instability.
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Affiliation(s)
- Kenji Keyamura
- Department of Life Science, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Kota Arai
- Department of Life Science, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Takashi Hishida
- Department of Life Science, Graduate School of Science, Gakushuin University, Tokyo, Japan
- * E-mail:
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36
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Géli V, Lisby M. Recombinational DNA repair is regulated by compartmentalization of DNA lesions at the nuclear pore complex. Bioessays 2015; 37:1287-92. [PMID: 26422820 DOI: 10.1002/bies.201500084] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The nuclear pore complex (NPC) is emerging as a center for recruitment of a class of "difficult to repair" lesions such as double-strand breaks without a repair template and eroded telomeres in telomerase-deficient cells. In addition to such pathological situations, a recent study by Su and colleagues shows that also physiological threats to genome integrity such as DNA secondary structure-forming triplet repeat sequences relocalize to the NPC during DNA replication. Mutants that fail to reposition the triplet repeat locus to the NPC cause repeat instability. Here, we review the types of DNA lesions that relocalize to the NPC, the putative mechanisms of relocalization, and the types of recombinational repair that are stimulated by the NPC, and present a model for NPC-facilitated repair.
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Affiliation(s)
- Vincent Géli
- Marseille Cancer Research Center (CRCM), U1068 Inserm, UMR7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, LNCC (Equipe labellisée), Marseille, France
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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37
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Blanco MG, Matos J. Hold your horSSEs: controlling structure-selective endonucleases MUS81 and Yen1/GEN1. Front Genet 2015; 6:253. [PMID: 26284109 PMCID: PMC4519697 DOI: 10.3389/fgene.2015.00253] [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: 05/12/2015] [Accepted: 07/13/2015] [Indexed: 12/21/2022] Open
Abstract
Repair of DNA lesions through homologous recombination promotes the establishment of stable chromosomal interactions. Multiple helicases, topoisomerases and structure-selective endonucleases (SSEs) act upon recombining joint molecules (JMs) to disengage chromosomal connections and safeguard chromosome segregation. Recent studies on two conserved SSEs – MUS81 and Yen1/GEN1– uncovered multiple layers of regulation that operate to carefully tailor JM-processing according to specific cellular needs. Temporal restriction of SSE function imposes a hierarchy in pathway usage that ensures efficient JM-processing while minimizing reciprocal exchanges between the recombining DNAs. Whereas a conserved strategy of fine-tuning SSE functions exists in different model systems, the precise molecular mechanisms to implement it appear to be significantly different. Here, we summarize the current knowledge on the cellular switches that are in place to control MUS81 and Yen1/GEN1 functions.
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Affiliation(s)
- Miguel G Blanco
- Department of Biochemistry and Molecular Biology, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela , Santiago de Compostela, Spain
| | - Joao Matos
- Institute of Biochemistry, Swiss Federal Institute of Technology in Zürich , Zürich, Switzerland
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38
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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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39
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Herrmann NJ, Knoll A, Puchta H. The nuclease FAN1 is involved in DNA crosslink repair in Arabidopsis thaliana independently of the nuclease MUS81. Nucleic Acids Res 2015; 43:3653-66. [PMID: 25779053 PMCID: PMC4402529 DOI: 10.1093/nar/gkv208] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/01/2015] [Indexed: 01/06/2023] Open
Abstract
Fanconi anemia is a severe genetic disorder. Mutations in one of several genes lead to defects in DNA crosslink (CL) repair in human cells. An essential step in CL repair is the activation of the pathway by the monoubiquitination of the heterodimer FANCD2/FANCI, which recruits the nuclease FAN1 to the CL site. Surprisingly, FAN1 function is not conserved between different eukaryotes. No FAN1 homolog is present in Drosophila and Saccharomyces cerevisiae. The FAN1 homolog in Schizosaccharomyces pombe is involved in CL repair; a homolog is present in Xenopus but is not involved in CL repair. Here we show that a FAN1 homolog is present in plants and it is involved in CL repair in Arabidopsis thaliana. Both the virus-type replication-repair nuclease and the ubiquitin-binding ubiquitin-binding zinc finger domains are essential for this function. FAN1 likely acts upstream of two sub-pathways of CL repair. These pathways are defined by the Bloom syndrome homolog RECQ4A and the ATPase RAD5A, which is involved in error-free post-replicative repair. Mutations in both FAN1 and the endonuclease MUS81 resulted in greater sensitivity against CLs than in the respective single mutants. These results indicate that the two nucleases define two independent pathways of CL repair in plants.
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Affiliation(s)
- Natalie J Herrmann
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstrasse 16, Karlsruhe, 76187, Germany
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Chavdarova M, Marini V, Sisakova A, Sedlackova H, Vigasova D, Brill SJ, Lisby M, Krejci L. Srs2 promotes Mus81-Mms4-mediated resolution of recombination intermediates. Nucleic Acids Res 2015; 43:3626-42. [PMID: 25765656 PMCID: PMC4402524 DOI: 10.1093/nar/gkv198] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/26/2015] [Indexed: 11/26/2022] Open
Abstract
A variety of DNA lesions, secondary DNA structures or topological stress within the DNA template may lead to stalling of the replication fork. Recovery of such forks is essential for the maintenance of genomic stability. The structure-specific endonuclease Mus81–Mms4 has been implicated in processing DNA intermediates that arise from collapsed forks and homologous recombination. According to previous genetic studies, the Srs2 helicase may play a role in the repair of double-strand breaks and ssDNA gaps together with Mus81–Mms4. In this study, we show that the Srs2 and Mus81–Mms4 proteins physically interact in vitro and in vivo and we map the interaction domains within the Srs2 and Mus81 proteins. Further, we show that Srs2 plays a dual role in the stimulation of the Mus81–Mms4 nuclease activity on a variety of DNA substrates. First, Srs2 directly stimulates Mus81–Mms4 nuclease activity independent of its helicase activity. Second, Srs2 removes Rad51 from DNA to allow access of Mus81–Mms4 to cleave DNA. Concomitantly, Mus81–Mms4 inhibits the helicase activity of Srs2. Taken together, our data point to a coordinated role of Mus81–Mms4 and Srs2 in processing of recombination as well as replication intermediates.
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Affiliation(s)
- Melita Chavdarova
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A4, Brno 625 00, Czech Republic
| | - Victoria Marini
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic
| | - Alexandra Sisakova
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Brno, Czech Republic
| | - Hana Sedlackova
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic
| | - Dana Vigasova
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Steven J Brill
- Department of Genetics, Cancer Research Institute, Vlarska 7, 833 91 Bratislava, Slovakia
| | - Michael Lisby
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, USA
| | - Lumir Krejci
- Department of Biology, Masaryk University, Kamenice 5/A7, Brno 625 00, Czech Republic National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A4, Brno 625 00, Czech Republic International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Brno, Czech Republic
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Thu HPT, Nguyen TA, Munashingha PR, Kwon B, Dao Van Q, Seo YS. A physiological significance of the functional interaction between Mus81 and Rad27 in homologous recombination repair. Nucleic Acids Res 2015; 43:1684-99. [PMID: 25628354 PMCID: PMC4330386 DOI: 10.1093/nar/gkv025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fen1 and Mus81-Mms4 are endonucleases involved in the processing of various DNA structural intermediates, and they were shown to have genetic and functional interactions with each other. Here, we show the in vivo significance of the interactions between Mus81 and Rad27 (yeast Fen1). The N-terminal 120 amino-acid (aa) region of Mus81, although entirely dispensable for its catalytic activity, was essential for the abilities of Mus81 to bind to and be stimulated by Rad27. In the absence of SGS1, the mus81Δ120N mutation lacking the N-terminal 120 aa region exhibited synthetic lethality, and the lethality was rescued by deletion of RAD52, a key homologous recombination mediator. These findings, together with the fact that Sgs1 constitutes a redundant pathway with Mus81-Mms4, indicate that the N-terminus-mediated interaction of Mus81 with Rad27 is physiologically important in resolving toxic recombination intermediates. Mutagenic analyses of the N-terminal region identified two distinct motifs, named N21-26 (aa from 21-26) and N108-114 (aa from 108-114) important for the in vitro and in vivo functions of Mus81. Our findings indicate that the N-terminal region of Mus81 acts as a landing pad to interact with Rad27 and that Mus81 and Rad27 work conjointly for efficient removal of various aberrant DNA structures.
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Affiliation(s)
- Huong Phung Thi Thu
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Tuan Anh Nguyen
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Palinda Ruvan Munashingha
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Buki Kwon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Quy Dao Van
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Yeon-Soo Seo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
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42
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Oke A, Anderson CM, Yam P, Fung JC. Controlling meiotic recombinational repair - specifying the roles of ZMMs, Sgs1 and Mus81/Mms4 in crossover formation. PLoS Genet 2014; 10:e1004690. [PMID: 25329811 PMCID: PMC4199502 DOI: 10.1371/journal.pgen.1004690] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/19/2014] [Indexed: 11/19/2022] Open
Abstract
Crossovers (COs) play a critical role in ensuring proper alignment and segregation of homologous chromosomes during meiosis. How the cell balances recombination between CO vs. noncrossover (NCO) outcomes is not completely understood. Further lacking is what constrains the extent of DNA repair such that multiple events do not arise from a single double-strand break (DSB). Here, by interpreting signatures that result from recombination genome-wide, we find that synaptonemal complex proteins promote crossing over in distinct ways. Our results suggest that Zip3 (RNF212) promotes biased cutting of the double Holliday-junction (dHJ) intermediate whereas surprisingly Msh4 does not. Moreover, detailed examination of conversion tracts in sgs1 and mms4-md mutants reveal distinct aberrant recombination events involving multiple chromatid invasions. In sgs1 mutants, these multiple invasions are generally multichromatid involving 3-4 chromatids; in mms4-md mutants the multiple invasions preferentially resolve into one or two chromatids. Our analysis suggests that Mus81/Mms4 (Eme1), rather than just being a minor resolvase for COs is crucial for both COs and NCOs in preventing chromosome entanglements by removing 3'- flaps to promote second-end capture. Together our results force a reevaluation of how key recombination enzymes collaborate to specify the outcome of meiotic DNA repair.
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Affiliation(s)
- Ashwini Oke
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center of Reproductive Sciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Carol M. Anderson
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center of Reproductive Sciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Phoebe Yam
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center of Reproductive Sciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Jennifer C. Fung
- Department of Obstetrics, Gynecology and Reproductive Sciences, Center of Reproductive Sciences, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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43
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Increased meiotic crossovers and reduced genome stability in absence of Schizosaccharomyces pombe Rad16 (XPF). Genetics 2014; 198:1457-72. [PMID: 25293972 DOI: 10.1534/genetics.114.171355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Schizosaccharomyces pombe Rad16 is the ortholog of the XPF structure-specific endonuclease, which is required for nucleotide excision repair and implicated in the single strand annealing mechanism of recombination. We show that Rad16 is important for proper completion of meiosis. In its absence, cells suffer reduced spore viability and abnormal chromosome segregation with evidence for fragmentation. Recombination between homologous chromosomes is increased, while recombination within sister chromatids is reduced, suggesting that Rad16 is not required for typical homolog crossovers but influences the balance of recombination between the homolog and the sister. In vegetative cells, rad16 mutants show evidence for genome instability. Similar phenotypes are associated with mutants affecting Rhp14(XPA) but are independent of other nucleotide excision repair proteins such as Rad13(XPG). Thus, the XPF/XPA module of the nucleotide excision repair pathway is incorporated into multiple aspects of genome maintenance even in the absence of external DNA damage.
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44
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Drosophila FANCM helicase prevents spontaneous mitotic crossovers generated by the MUS81 and SLX1 nucleases. Genetics 2014; 198:935-45. [PMID: 25205745 DOI: 10.1534/genetics.114.168096] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Several helicases function during repair of double-strand breaks and handling of blocked or stalled replication forks to promote pathways that prevent formation of crossovers. Among these are the Bloom syndrome helicase BLM and the Fanconi anemia group M (FANCM) helicase. To better understand functions of these helicases, we compared phenotypes of Drosophila melanogaster Blm and Fancm mutants. As previously reported for BLM, FANCM has roles in responding to several types of DNA damage in preventing mitotic and meiotic crossovers and in promoting the synthesis-dependent strand annealing pathway for repair of a double-strand gap. In most assays, the phenotype of Fancm mutants is less severe than that of Blm mutants, and the phenotype of Blm Fancm double mutants is more severe than either single mutant, indicating both overlapping and unique functions. It is thought that mitotic crossovers arise when structure-selective nucleases cleave DNA intermediates that would normally be unwound or disassembled by these helicases. When BLM is absent, three nucleases believed to function as Holliday junction resolvases--MUS81-MMS4, MUS312-SLX1, and GEN--become essential. In contrast, no single resolvase is essential in mutants lacking FANCM, although simultaneous loss of GEN and either of the others is lethal in Fancm mutants. Since Fancm mutants can tolerate loss of a single resolvase, we were able to show that spontaneous mitotic crossovers that occur when FANCM is missing are dependent on MUS312 and either MUS81 or SLX1.
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45
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Abstract
Four-way DNA intermediates, called Holliday junctions (HJs), can form during meiotic and mitotic recombination, and their removal is crucial for chromosome segregation. A group of ubiquitous and highly specialized structure-selective endonucleases catalyze the cleavage of HJs into two disconnected DNA duplexes in a reaction called HJ resolution. These enzymes, called HJ resolvases, have been identified in bacteria and their bacteriophages, archaea, and eukaryotes. In this review, we discuss fundamental aspects of the HJ structure and their interaction with junction-resolving enzymes. This is followed by a brief discussion of the eubacterial RuvABC enzymes, which provide the paradigm for HJ resolvases in other organisms. Finally, we review the biochemical and structural properties of some well-characterized resolvases from archaea, bacteriophage, and eukaryotes.
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Affiliation(s)
- Haley D M Wyatt
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, United Kingdom
| | - Stephen C West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, United Kingdom
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46
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Signon L, Simon MN. The analysis of S. cerevisiae cells deleted for mitotic cyclin Clb2 reveals a novel requirement of Sgs1 DNA helicase and Exonuclease 1 when replication forks break in the presence of alkylation damage. Mutat Res 2014; 769:80-92. [PMID: 25771727 DOI: 10.1016/j.mrfmmm.2014.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 07/19/2014] [Accepted: 07/22/2014] [Indexed: 10/25/2022]
Abstract
In this study, we report the effects of deleting the principal mitotic cyclin, Clb2, in different repair deficient contexts on sensitivity to the alkylating DNA damaging agent, methyl methanesulphonate (MMS). A yeast clb2 mutant is sensitive to MMS and displays synergistic effect when combined with inactivation of numerous genes involved in DNA recombination and replication. In contrast, clb2 has basically no additional effect with deletion of the RecQ helicase SGS1, the exonuclease EXO1 and the protein kinase RAD53 suggesting that Clb2 functions in these pathways. In addition, clb2 increases the viability of the mec1 kinase deficient mutant, suggesting Mec1 inhibits a deleterious Clb2 activity. Interestingly, we found that the rescue by EXO1 deletion of rad53K227 mutant, deficient in checkpoint activation, requires Sgs1, suggesting a role for Rad53, independent of its checkpoint function, in regulating an ordered recruitment of Sgs1 and Exo1 to fork structure. Overall, our data suggest that Clb2 affects recombinant structure of replication fork blocked by alkylating DNA damage at numerous steps and could regulate Sgs1 and Exo1 activity. In addition, we found novel requirement of Sgs1 DNA helicase and Exonuclease 1 when replication forks breaks in the presence of alkylation damage. Models for the functional interactions of mitotic cyclin Clb2, Sgs1 and Exo1 with replication fork stabilization are proposed.
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Affiliation(s)
- Laurence Signon
- Laboratoire d'Ingenierie des Systèmes Macromoléculaires CNRS UPR9027, Aix-Marseille University, 13402 Marseille Cedex 20, France; Université Paris-Sud, CNRS UMR8621, Institut de Génétique et Microbiologie, Bâtiment 400, 91405 Orsay Cedex, France.
| | - Marie Noelle Simon
- Laboratoire d'Ingenierie des Systèmes Macromoléculaires CNRS UPR9027, Aix-Marseille University, 13402 Marseille Cedex 20, France
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47
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Abstract
Double Holliday junctions (dHJS) are important intermediates of homologous recombination. The separate junctions can each be cleaved by DNA structure-selective endonucleases known as Holliday junction resolvases. Alternatively, double Holliday junctions can be processed by a reaction known as "double Holliday junction dissolution." This reaction requires the cooperative action of a so-called "dissolvasome" comprising a Holliday junction branch migration enzyme (Sgs1/BLM RecQ helicase) and a type IA topoisomerase (Top3/TopoIIIα) in complex with its OB (oligonucleotide/oligosaccharide binding) fold containing accessory factor (Rmi1). This review details our current knowledge of the dissolution process and the players involved in catalyzing this mechanistically complex means of completing homologous recombination reactions.
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Affiliation(s)
- Anna H Bizard
- Nordea Center for Healthy Aging, Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Nordea Center for Healthy Aging, Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, 2200 Copenhagen N, Denmark
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48
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Dangel NJ, Knoll A, Puchta H. MHF1 plays Fanconi anaemia complementation group M protein (FANCM)-dependent and FANCM-independent roles in DNA repair and homologous recombination in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:822-833. [PMID: 24635147 DOI: 10.1111/tpj.12507] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 02/28/2014] [Accepted: 03/06/2014] [Indexed: 06/03/2023]
Abstract
Fanconi anaemia complementation group M protein (FANCM), a component of the human Fanconi anemia pathway, acts as DNA translocase that is essential during the repair of DNA interstrand cross-links. The DNA-damage-binding function of FANCM is strongly enhanced by the histone fold-containing FANCM-associated protein MHF1. We identified a single homologue of MHF1 in the genome of Arabidopsis thaliana. Similar to the loss of AtFANCM, the loss of AtMHF1 leads to several meiotic defects, such as chromosome bridges between bivalents and an unequal distribution of chromosomes. Moreover, MHF1, together with FANCM, is involved in interstrand cross-link repair in plants. This phenotype is detectable only in double mutants of the RecQ helicase and BLM homologue RECQ4A, which appears to function in a parallel pathway to the FANCM/MHF1 complex. However, in somatic cells, FANCM has an MHF1-independent function in replicative repair in a parallel pathway to the endonuclease MUS81. Furthermore, MHF1 is required for efficient somatic homologous recombination (HR) - a role antagonistic to FANCM. FANCM and RECQ4A define two parallel pathways of HR suppression in Arabidopsis. Hyperrecombination in the fancm but not the recq4A mutant can be abolished by MHF1 mutations. This finding indicates that MHF1 and FANCM act at different steps of a single, common, HR pathway.
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Affiliation(s)
- Natalie J Dangel
- Botanical Institute II, Karlsruhe Institute of Technology, Hertzstr. 16, Karlsruhe, 76187, Germany
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Pepe A, West SC. MUS81-EME2 promotes replication fork restart. Cell Rep 2014; 7:1048-55. [PMID: 24813886 PMCID: PMC5092538 DOI: 10.1016/j.celrep.2014.04.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/04/2014] [Accepted: 04/04/2014] [Indexed: 12/11/2022] Open
Abstract
Replication forks frequently stall at regions of the genome that are difficult to replicate or contain lesions that cause replication blockage. An important mechanism for the restart of a stalled fork involves endonucleolytic cleavage that can lead to fork restoration and replication progression. Here, we show that the structure-selective endonuclease MUS81-EME2 is responsible for fork cleavage and restart in human cells. The MUS81-EME2 protein, whose actions are restricted to S phase, is also responsible for telomere maintenance in telomerase-negative ALT (Alternative Lengthening of Telomeres) cells. In contrast, the G2/M functions of MUS81, such as the cleavage of recombination intermediates and fragile site expression, are promoted by MUS81-EME1. These results define distinct and temporal roles for MUS81-EME1 and MUS81-EME2 in the maintenance of genome stability.
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Affiliation(s)
- Alessandra Pepe
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
| | - Stephen C West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK.
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50
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Blanco MG, Matos J, West SC. Dual control of Yen1 nuclease activity and cellular localization by Cdk and Cdc14 prevents genome instability. Mol Cell 2014; 54:94-106. [PMID: 24631285 PMCID: PMC3988869 DOI: 10.1016/j.molcel.2014.02.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/04/2014] [Accepted: 02/03/2014] [Indexed: 02/01/2023]
Abstract
The careful orchestration of cellular events such as DNA replication, repair, and segregation is essential for equal distribution of the duplicated genome into two daughter cells. To ensure that persistent recombination intermediates are resolved prior to cell division, the Yen1 Holliday junction resolvase is activated at anaphase. Here, we show that the master cell-cycle regulators, cyclin-dependent kinase (Cdk) and Cdc14 phosphatase, control the actions of Yen1. During S phase, Cdk-mediated phosphorylation of Yen1 promotes its nuclear exclusion and inhibits catalytic activity by reducing the efficiency of DNA binding. Later in the cell cycle, at anaphase, Cdc14 drives Yen1 dephosphorylation, leading to its nuclear relocalization and enzymatic activation. Using a constitutively activated form of Yen1, we show that uncontrolled Yen1 activity is detrimental to the cell: spatial and temporal restriction of Yen1 protects against genotoxic stress and, by avoiding competition with the noncrossover-promoting repair pathways, prevents loss of heterozygosity.
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Affiliation(s)
- Miguel G Blanco
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
| | - Joao Matos
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
| | - Stephen C West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK.
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