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Ito M, Fujita Y, Shinohara A. Positive and negative regulators of RAD51/DMC1 in homologous recombination and DNA replication. DNA Repair (Amst) 2024; 134:103613. [PMID: 38142595 DOI: 10.1016/j.dnarep.2023.103613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023]
Abstract
RAD51 recombinase plays a central role in homologous recombination (HR) by forming a nucleoprotein filament on single-stranded DNA (ssDNA) to catalyze homology search and strand exchange between the ssDNA and a homologous double-stranded DNA (dsDNA). The catalytic activity of RAD51 assembled on ssDNA is critical for the DNA-homology-mediated repair of DNA double-strand breaks in somatic and meiotic cells and restarting stalled replication forks during DNA replication. The RAD51-ssDNA complex also plays a structural role in protecting the regressed/reversed replication fork. Two types of regulators control RAD51 filament formation, stability, and dynamics, namely positive regulators, including mediators, and negative regulators, so-called remodelers. The appropriate balance of action by the two regulators assures genome stability. This review describes the roles of positive and negative RAD51 regulators in HR and DNA replication and its meiosis-specific homolog DMC1 in meiotic recombination. We also provide future study directions for a comprehensive understanding of RAD51/DMC1-mediated regulation in maintaining and inheriting genome integrity.
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Affiliation(s)
- Masaru Ito
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Yurika Fujita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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2
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Cullati SN, Zhang E, Shan Y, Guillen RX, Chen JS, Navarrete-Perea J, Elmore ZC, Ren L, Gygi SP, Gould KL. Fission yeast CK1 promotes DNA double-strand break repair through both homologous recombination and non-homologous end joining. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.538600. [PMID: 37162912 PMCID: PMC10168346 DOI: 10.1101/2023.04.27.538600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The CK1 family are conserved serine/threonine kinases with numerous substrates and cellular functions. The fission yeast CK1 orthologues Hhp1 and Hhp2 were first characterized as regulators of DNA repair, but the mechanism(s) by which CK1 activity promotes DNA repair had not been investigated. Here, we found that deleting Hhp1 and Hhp2 or inhibiting CK1 catalytic activities in yeast or in human cells activated the DNA damage checkpoint due to persistent double-strand breaks (DSBs). The primary pathways to repair DSBs, homologous recombination and non-homologous end joining, were both less efficient in cells lacking Hhp1 and Hhp2 activity. In order to understand how Hhp1 and Hhp2 promote DSB repair, we identified new substrates using quantitative phosphoproteomics. We confirmed that Arp8, a component of the INO80 chromatin remodeling complex, is a bona fide substrate of Hhp1 and Hhp2 that is important for DSB repair. Our data suggest that Hhp1 and Hhp2 facilitate DSB repair by phosphorylating multiple substrates, including Arp8.
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Affiliation(s)
- Sierra N. Cullati
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric Zhang
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Current address: Columbia University Medical Center, New York, NY, USA
| | - Yufan Shan
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rodrigo X. Guillen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Zachary C. Elmore
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Current address: Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
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3
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DNA Repair in Haploid Context. Int J Mol Sci 2021; 22:ijms222212418. [PMID: 34830299 PMCID: PMC8620282 DOI: 10.3390/ijms222212418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/08/2021] [Accepted: 11/14/2021] [Indexed: 12/15/2022] Open
Abstract
DNA repair is a well-covered topic as alteration of genetic integrity underlies many pathological conditions and important transgenerational consequences. Surprisingly, the ploidy status is rarely considered although the presence of homologous chromosomes dramatically impacts the repair capacities of cells. This is especially important for the haploid gametes as they must transfer genetic information to the offspring. An understanding of the different mechanisms monitoring genetic integrity in this context is, therefore, essential as differences in repair pathways exist that differentiate the gamete’s role in transgenerational inheritance. Hence, the oocyte must have the most reliable repair capacity while sperm, produced in large numbers and from many differentiation steps, are expected to carry de novo variations. This review describes the main DNA repair pathways with a special emphasis on ploidy. Differences between Saccharomyces cerevisiae and Schizosaccharomyces pombe are especially useful to this aim as they can maintain a diploid and haploid life cycle respectively.
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4
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Escorcia W, Tripathi VP, Yuan JP, Forsburg SL. A visual atlas of meiotic protein dynamics in living fission yeast. Open Biol 2021; 11:200357. [PMID: 33622106 PMCID: PMC8061692 DOI: 10.1098/rsob.200357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Meiosis is a carefully choreographed dynamic process that re-purposes proteins from somatic/vegetative cell division, as well as meiosis-specific factors, to carry out the differentiation and recombination pathway common to sexually reproducing eukaryotes. Studies of individual proteins from a variety of different experimental protocols can make it difficult to compare details between them. Using a consistent protocol in otherwise wild-type fission yeast cells, this report provides an atlas of dynamic protein behaviour of representative proteins at different stages during normal zygotic meiosis in fission yeast. This establishes common landmarks to facilitate comparison of different proteins and shows that initiation of S phase likely occurs prior to nuclear fusion/karyogamy.
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Affiliation(s)
- Wilber Escorcia
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA.,Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 45207, USA
| | - Vishnu P Tripathi
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Ji-Ping Yuan
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
| | - Susan L Forsburg
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, CA 90089, USA
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5
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Escorcia W, Forsburg SL. Destabilization of the replication fork protection complex disrupts meiotic chromosome segregation. Mol Biol Cell 2017; 28:2978-2997. [PMID: 28855376 PMCID: PMC5662257 DOI: 10.1091/mbc.e17-02-0101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 12/17/2022] Open
Abstract
The replication fork protection complex (FPC) coordinates multiple processes that are crucial for unimpeded passage of the replisome through various barriers and difficult to replicate areas of the genome. We examine the function of Swi1 and Swi3, fission yeast's primary FPC components, to elucidate how replication fork stability contributes to DNA integrity in meiosis. We report that destabilization of the FPC results in reduced spore viability, delayed replication, changes in recombination, and chromosome missegregation in meiosis I and meiosis II. These phenotypes are linked to accumulation and persistence of DNA damage markers in meiosis and to problems with cohesion stability at the centromere. These findings reveal an important connection between meiotic replication fork stability and chromosome segregation, two processes with major implications to human reproductive health.
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Affiliation(s)
- Wilber Escorcia
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089-2910
| | - Susan L Forsburg
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089-2910
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6
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Aronica L, Kasparek T, Ruchman D, Marquez Y, Cipak L, Cipakova I, Anrather D, Mikolaskova B, Radtke M, Sarkar S, Pai CC, Blaikley E, Walker C, Shen KF, Schroeder R, Barta A, Forsburg SL, Humphrey TC. The spliceosome-associated protein Nrl1 suppresses homologous recombination-dependent R-loop formation in fission yeast. Nucleic Acids Res 2015; 44:1703-17. [PMID: 26682798 PMCID: PMC4770224 DOI: 10.1093/nar/gkv1473] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 12/03/2015] [Indexed: 01/07/2023] Open
Abstract
The formation of RNA–DNA hybrids, referred to as R-loops, can promote genome instability and cancer development. Yet the mechanisms by which R-loops compromise genome instability are poorly understood. Here, we establish roles for the evolutionarily conserved Nrl1 protein in pre-mRNA splicing regulation, R-loop suppression and in maintaining genome stability. nrl1Δ mutants exhibit endogenous DNA damage, are sensitive to exogenous DNA damage, and have defects in homologous recombination (HR) repair. Concomitantly, nrl1Δ cells display significant changes in gene expression, similar to those induced by DNA damage in wild-type cells. Further, we find that nrl1Δ cells accumulate high levels of R-loops, which co-localize with HR repair factors and require Rad51 and Rad52 for their formation. Together, our findings support a model in which R-loop accumulation and subsequent DNA damage sequesters HR factors, thereby compromising HR repair at endogenously or exogenously induced DNA damage sites, leading to genome instability.
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Affiliation(s)
- Lucia Aronica
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria Department of Oncology, Stanford University, Stanford 94305, USA
| | - Torben Kasparek
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - David Ruchman
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Yamile Marquez
- Department of Medical Biochemistry, Max F. Perutz Laboratories,Medical University of Vienna, Vienna A-1030, Austria
| | - Lubos Cipak
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Ingrid Cipakova
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Dorothea Anrather
- Max F. Perutz Laboratories, Mass Spectrometry Facility, Vienna A-1030, Austria
| | - Barbora Mikolaskova
- Cancer Research Institute, Slovak Academy of Sciences, Bratislava 81438, Slovakia
| | - Maximilian Radtke
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Sovan Sarkar
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - Chen-Chun Pai
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | | | - Carol Walker
- CRUK/MRC Oxford Institute for Radiation Oncology, Oxford OX37DQ , UK
| | - Kuo-Fang Shen
- University of Southern California, Los Angeles 90089-0911, USA
| | - Renee Schroeder
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, Vienna A-1030, Austria
| | - Andrea Barta
- Department of Medical Biochemistry, Max F. Perutz Laboratories,Medical University of Vienna, Vienna A-1030, Austria
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7
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Campos-Góngora E, Andaluz E, Bellido A, Ruiz-Herrera J, Larriba G. The RAD52 ortholog of Yarrowia lipolytica is essential for nuclear integrity and DNA repair. FEMS Yeast Res 2013; 13:441-52. [PMID: 23566019 DOI: 10.1111/1567-1364.12047] [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: 11/30/2012] [Revised: 03/22/2013] [Accepted: 04/02/2013] [Indexed: 11/27/2022] Open
Abstract
Yarrowia lipolytica (Yl) is a dimorphic fungus that has become a well-established model for a number of biological processes, including secretion of heterologous and chimerical proteins. However, little is known on the recombination machinery responsible for the integration in the genome of the exogenous DNA encoding for those proteins. We have carried out a phenotypic analysis of rad52 deletants of Y. lipolytica. YlRad52 exhibited 20-30% identity with Rad52 homologues of other eukaryotes, including Saccharomyces cerevisiae and Candida albicans. Ylrad52-Δ strains formed colonies on YPD-agar plates which were spinier and smaller than those from wild type, whereas in YPD liquid cultures they exhibited a decreased grow rate and contained cells with aberrant morphology and fragmented chromatin, supporting a role for homologous recombination (HR) in genome stability under nondamaging conditions. In addition, Ylrad52 mutants showed moderate to high sensitivity to UV light, oxidizing agents and compounds that cause single- (SSB) and double-strand breaks (DSB), indicating an important role for Rad52 in DNA repair. These findings extend to Yl previous observations indicating that RAD52 is a crucial gene for DNA repair in other fungi, including S. cerevisiae, C. albicans and Schizosaccharomyces pombe.
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Affiliation(s)
- Eduardo Campos-Góngora
- Centro de Investigación en Nutrición y Salud Pública, Universidad Autónoma de Nuevo León, Monterrey, NL, México
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8
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Fission yeast Pot1 and RecQ helicase are required for efficient chromosome segregation. Mol Cell Biol 2010; 31:495-506. [PMID: 21098121 DOI: 10.1128/mcb.00613-10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pot1 is a single-stranded telomere-binding protein that is conserved from fission yeast to mammals. Deletion of Schizosaccharomyces pombe pot1(+) causes immediate telomere loss. S. pombe Rqh1 is a homolog of the human RecQ helicase WRN, which plays essential roles in the maintenance of genomic stability. Here, we demonstrate that a pot1Δ rqh1-hd (helicase-dead) double mutant maintains telomeres that are dependent on Rad51-mediated homologous recombination. Interestingly, the pot1Δ rqh1-hd double mutant displays a "cut" (cell untimely torn) phenotype and is sensitive to the antimicrotubule drug thiabendazole (TBZ). Moreover, the chromosome ends of the double mutant do not enter the pulsed-field electrophoresis gel. These results suggest that the entangled chromosome ends in the pot1Δ rqh1-hd double mutant inhibit chromosome segregation, signifying that Pot1 and Rqh1 are required for efficient chromosome segregation. We also found that POT1 knockdown, WRN-deficient human cells are sensitive to the antimicrotubule drug vinblastine, implying that some of the functions of S. pombe Pot1 and Rqh1 may be conserved in their respective human counterparts POT1 and WRN.
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9
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Hyppa RW, Smith GR. Crossover invariance determined by partner choice for meiotic DNA break repair. Cell 2010; 142:243-55. [PMID: 20655467 PMCID: PMC2911445 DOI: 10.1016/j.cell.2010.05.041] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 03/23/2010] [Accepted: 05/18/2010] [Indexed: 11/21/2022]
Abstract
Crossovers between meiotic homologs are crucial for their proper segregation, and crossover number and position are carefully controlled. Crossover homeostasis in budding yeast maintains crossovers at the expense of noncrossovers when double-strand DNA break (DSB) frequency is reduced. The mechanism of maintaining constant crossover levels in other species has been unknown. Here we investigate in fission yeast a different aspect of crossover control--the near invariance of crossover frequency per kb of DNA despite large variations in DSB intensity across the genome. Crossover invariance involves the choice of sister chromatid versus homolog for DSB repair. At strong DSB hotspots, intersister repair outnumbers interhomolog repair approximately 3:1, but our genetic and physical data indicate the converse in DSB-cold regions. This unanticipated mechanism of crossover control may operate in many species and explain, for example, the large excess of DSBs over crossovers and the repair of DSBs on unpaired chromosomes in diverse species.
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Affiliation(s)
- Randy W. Hyppa
- Fred Hutchinson Cancer Research Center Division of Basic Sciences Seattle, WA 98109 USA
| | - Gerald R. Smith
- Fred Hutchinson Cancer Research Center Division of Basic Sciences Seattle, WA 98109 USA
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10
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Tinline-Purvis H, Savory AP, Cullen JK, Davé A, Moss J, Bridge WL, Marguerat S, Bähler J, Ragoussis J, Mott R, Walker CA, Humphrey TC. Failed gene conversion leads to extensive end processing and chromosomal rearrangements in fission yeast. EMBO J 2009; 28:3400-12. [PMID: 19798055 DOI: 10.1038/emboj.2009.265] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 08/17/2009] [Indexed: 01/06/2023] Open
Abstract
Loss of heterozygosity (LOH), a causal event in cancer and human genetic diseases, frequently encompasses multiple genetic loci and whole chromosome arms. However, the mechanisms by which such extensive LOH arises, and how it is suppressed in normal cells is poorly understood. We have developed a genetic system to investigate the mechanisms of DNA double-strand break (DSB)-induced extensive LOH, and its suppression, using a non-essential minichromosome, Ch(16), in fission yeast. We find extensive LOH to arise from a new break-induced mechanism of isochromosome formation. Our data support a model in which Rqh1 and Exo1-dependent end processing from an unrepaired DSB leads to removal of the broken chromosome arm and to break-induced replication of the intact arm from the centromere, a considerable distance from the initial lesion. This process also promotes genome-wide copy number variation. A genetic screen revealed Rhp51, Rhp55, Rhp57 and the MRN complex to suppress both isochromosome formation and chromosome loss, in accordance with these events resulting from extensive end processing associated with failed homologous recombination repair.
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Affiliation(s)
- Helen Tinline-Purvis
- CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, Oxfordshire, UK
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11
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Khasanov FK, Salakhova AF, Khasanova OS, Grishchuk AL, Chepurnaja OV, Korolev VG, Kohli J, Bashkirov VI. Genetic analysis reveals different roles of Schizosaccharomyces pombe sfr1/dds20 in meiotic and mitotic DNA recombination and repair. Curr Genet 2008; 54:197-211. [PMID: 18769921 DOI: 10.1007/s00294-008-0212-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 08/15/2008] [Indexed: 11/26/2022]
Abstract
DNA double-strand break (DSB) repair mediated by the Rad51 pathway of homologous recombination is conserved in eukaryotes. In yeast, Rad51 paralogs, Saccharomyces cerevisiae Rad55-Rad57 and Schizosaccharomyces pombe Rhp55-Rhp57, are mediators of Rad51 nucleoprotein formation. The recently discovered S. pombe Sfr1/Dds20 protein has been shown to interact with Rad51 and to operate in the Rad51-dependent DSB repair pathway in parallel to the paralog-mediated pathway. Here we show that Sfr1 is a nuclear protein and acts downstream of Rad50 in DSB processing. sfr1Delta is epistatic to rad18 (-) and rad60 (-), and Sfr1 is a high-copy suppressor of the replication and repair defects of a rad60 mutant. Sfr1 functions in a Cds1-independent UV damage tolerance mechanism. In contrast to mitotic recombination, meiotic recombination is significantly reduced in sfr1Delta strains. Our data indicate that Sfr1 acts in DSB repair mainly outside of S-phase, and is required for wild-type levels of meiotic recombination. We suggest that Sfr1 acts early in recombination and has a specific role in Rad51 filament assembly, distinct from that of the Rad51 paralogs.
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Affiliation(s)
- Fuat K Khasanov
- Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
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12
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The Rad52 homologs Rad22 and Rti1 of Schizosaccharomyces pombe are not essential for meiotic interhomolog recombination, but are required for meiotic intrachromosomal recombination and mating-type-related DNA repair. Genetics 2008; 178:2399-412. [PMID: 18430957 DOI: 10.1534/genetics.107.085696] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteins of the RAD52 epistasis group play an essential role in repair of some types of DNA damage and genetic recombination. In Schizosaccharomyces pombe, Rad22 (a Rad52 ortholog) has been shown to be as necessary for repair and recombination events during vegetative growth as its Saccharomyces cerevisiae counterpart. This finding contrasts with previous reports where, due to suppressor mutations in the fbh1 gene, rad22 mutants did not display a severe defect. We have analyzed the roles of Rad22 and Rti1, another Rad52 homolog, during meiotic recombination and meiosis in general. Both proteins play an important role in spore viability. During meiotic prophase I, they partially colocalize and partially localize to Rad51 foci and linear elements. Genetic analysis showed that meiotic interchromosomal crossover and conversion events were unexpectedly not much affected by deletion of either or both genes. A strong decrease of intrachromosomal recombination assayed by a gene duplication construct was observed. Therefore, we propose that the most important function of Rad22 and Rti1 in S. pombe meiosis is repair of double-strand breaks with involvement of the sister chromatids. In addition, a novel mating-type-related repair function of Rad22 specific to meiosis and spore germination is described.
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13
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Radiation induction of delayed recombination in Schizosaccharomyces pombe. DNA Repair (Amst) 2008; 7:1250-61. [PMID: 18547878 DOI: 10.1016/j.dnarep.2008.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 02/15/2008] [Accepted: 04/05/2008] [Indexed: 11/24/2022]
Abstract
Ionizing radiation is known to induce delayed chromosome and gene mutations in the descendants of the irradiated tissue culture cells. Molecular mechanisms of such delayed mutations are yet to be elucidated, since high genomic complexity of mammalian cells makes it difficult to analyze. We now tested radiation induction of delayed recombination in the fission yeast Schizosaccharomyces pombe by monitoring the frequency of homologous recombination after X-irradiation. A reporter with 200 bp tandem repeats went through spontaneous recombination at a frequency of 1.0 x 10(-4), and the frequency increased dose-dependently to around 10 x 10(-4) at 500 Gy of X-irradiation. Although the repair of initial DNA damage was thought to be completed before the restart of cell division cycle, the elevation of the recombination frequency persisted for 8-10 cell generations after irradiation (delayed recombination). The delayed recombination suggests that descendants of the irradiated cells keep a memory of the initial DNA damage which upregulates recombination machinery for 8-10 generations even in the absence of DNA double-strand breaks (DSBs). Since radical scavengers were ineffective in inhibiting the delayed recombination, a memory by continuous production of DNA damaging agents such as reactive oxygen species (ROS) was excluded. Recombination was induced in trans in a reporter on chromosome III by a DNA DSB at a site on chromosome I, suggesting the untargeted nature of delayed recombination. Interestingly, Rad22 foci persisted in the X-irradiated population in parallel with the elevation of the recombination frequency. These results suggest that the epigenetic damage memory induced by DNA DSB upregulates untargeted and delayed recombination in S. pombe.
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14
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Decottignies A. Microhomology-mediated end joining in fission yeast is repressed by pku70 and relies on genes involved in homologous recombination. Genetics 2007; 176:1403-15. [PMID: 17483423 PMCID: PMC1931558 DOI: 10.1534/genetics.107.071621] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Two DNA repair pathways are known to mediate DNA double-strand-break (DSB) repair: homologous recombination (HR) and nonhomologous end joining (NHEJ). In addition, a nonconservative backup pathway showing extensive nucleotide loss and relying on microhomologies at repair junctions was identified in NHEJ-deficient cells from a variety of organisms and found to be involved in chromosomal translocations. Here, an extrachromosomal assay was used to characterize this microhomology-mediated end-joining (MMEJ) mechanism in fission yeast. MMEJ was found to require at least five homologous nucleotides and its efficiency was decreased by the presence of nonhomologous nucleotides either within the overlapping sequences or at DSB ends. Exo1 exonuclease and Rad22, a Rad52 homolog, were required for repair, suggesting that MMEJ is related to the single-strand-annealing (SSA) pathway of HR. In addition, MMEJ-dependent repair of DSBs with discontinuous microhomologies was strictly dependent on Pol4, a PolX DNA polymerase. Although not strictly required, Msh2 and Pms1 mismatch repair proteins affected the pattern of MMEJ repair. Strikingly, Pku70 inhibited MMEJ and increased the minimal homology length required for efficient MMEJ. Overall, this study strongly suggests that MMEJ does not define a distinct DSB repair mechanism but reflects "micro-SSA."
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Affiliation(s)
- Anabelle Decottignies
- Cellular Genetics, Christian de Duve Institute of Cellular Pathology, Catholic University of Louvain, 1200 Brussels, Belgium.
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15
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Raji H, Hartsuiker E. Double-strand break repair and homologous recombination in Schizosaccharomyces pombe. Yeast 2007; 23:963-76. [PMID: 17072889 DOI: 10.1002/yea.1414] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The study of double-strand break repair and homologous recombination in Saccharomyces cerevisiae meiosis has provided important information about the mechanisms involved. However, it has become clear that the resulting recombination models are only partially applicable to repair in mitotic cells, where crossover formation is suppressed. In recent years our understanding of double-strand break repair and homologous recombination in Schizosaccharomyces pombe has increased significantly, and the identification of novel pathways and genes with homologues in higher eukaryotes has increased its value as a model organism for double-strand break repair. In this review we will focus on the involvement of homologous recombination and repair in different aspects of genome stability in Sz. pombe meiosis, replication and telomere maintenance. We will also discuss anti-recombination pathways (that suppress crossover formation), non-homologous end-joining, single-strand annealing and factors that influence the choice and prevalence of the different repair pathways in Sz. pombe.
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Affiliation(s)
- Hayatu Raji
- Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK
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16
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de Vries FAT, Zonneveld JBM, de Groot AJ, Koning RI, van Zeeland AA, Pastink A. Schizosaccharomyces pombe Rad22A and Rad22B have similar biochemical properties and form multimeric structures. Mutat Res 2006; 615:143-52. [PMID: 17208257 DOI: 10.1016/j.mrfmmm.2006.11.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 11/10/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
The Saccharomyces cerevisiae Rad52 protein has a crucial role in the repair of DNA double-strand breaks by homologous recombination. In vitro, Rad52 displays DNA binding and strand annealing activities and promotes Rad51-mediated strand exchange. Schizosaccharomyces pombe has two Rad52 homologues, Rad22A and Rad22B. Whereas rad22A deficient strains exhibit severe defects in repair and recombination, rad22B mutants have a much less severe phenotype. To better understand the role of Rad22A and Rad22B in double-strand break repair, both proteins were purified to near homogeneity. Using gel retardation and filter binding assays, binding of Rad22A and Rad22B to short single-stranded DNAs was demonstrated. Binding of Rad22A to double-stranded oligonucleotides or linearized plasmid molecules containing blunt ends or short single-stranded overhangs could not be detected. Rad22B also does not bind efficiently to short duplex oligonucleotides but binds readily to DNA fragments containing 3'-overhangs. Rad22A as well as Rad22B efficiently promote annealing of complementary single-stranded DNAs. In the presence of Rad22A annealing of complementary DNAs is almost 90%. Whereas in reactions containing Rad22B the maximum level of annealing is 60%, most likely due to inhibition of the reaction by duplex DNA. Gel-filtration experiments and electron microscopic analyses indicate self-association of Rad22A and Rad22B and the formation of multimeric structures as has been observed for Rad52 in yeast and man.
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Affiliation(s)
- Femke A T de Vries
- Department of Toxicogenetics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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17
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Andaluz E, Ciudad T, Gómez-Raja J, Calderone R, Larriba G. Rad52 depletion in Candida albicans triggers both the DNA-damage checkpoint and filamentation accompanied by but independent of expression of hypha-specific genes. Mol Microbiol 2006; 59:1452-72. [PMID: 16468988 DOI: 10.1111/j.1365-2958.2005.05038.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have analysed the effect of RAD52 deletion in several aspects of the cell biology of Candida albicans. Cultures of rad52Delta strains exhibited slow growth and contained abundant cells with a filamentous morphology. Filamentation with polarization of actin patches was accompanied by the induction of the hypha-specific genes (HSG) ECE1, HWP1 and HGC1. However, filament formation occurred in the absence of the transcription factors Efg1 and Cph1, even though disruption of EFG1 prevented expression of HSG. Therefore, expression of HSG genes accompanies but is dispensable for rad52Delta filamentation. However, deletion of adenylate cyclase severely impaired filamentation, this effect being largely reverted by the addition of exogenous cAMP. Filaments resembled elongated pseudohyphae, but some of them looked like true hyphae. Following depletion of Rad52, many cells arrested at the G2/M phase of the cell cycle with a single nucleus suggesting the early induction of the DNA-damage checkpoint. Filaments formed later, preferentially from G2/M cells. The filamentation process was accompanied by the uncoupling of several landmark events of the cell cycle and was partially dependent on the action of the cell cycle modulator Swe1. Hyphae were still induced by serum, but a large number of rad52 cells myceliated in G2/M.
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Affiliation(s)
- Encarnación Andaluz
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
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18
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Coulon S, Noguchi E, Noguchi C, Du LL, Nakamura TM, Russell P. Rad22Rad52-dependent repair of ribosomal DNA repeats cleaved by Slx1-Slx4 endonuclease. Mol Biol Cell 2006; 17:2081-90. [PMID: 16467377 PMCID: PMC1415312 DOI: 10.1091/mbc.e05-11-1006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Slx1 and Slx4 are subunits of a structure-specific DNA endonuclease that is found in Saccharomyces cerevisiae, Schizosaccharomyces pombe, and other eukaryotic species. It is thought to initiate recombination events or process recombination structures that occur during the replication of the tandem repeats of the ribosomal DNA (rDNA) locus. Here, we present evidence that fission yeast Slx1-Slx4 initiates homologous recombination events in the rDNA repeats that are processed by a mechanism that requires Rad22 (Rad52 homologue) but not Rhp51 (Rad51 homologue). Slx1 is required to generate approximately 50% of the spontaneous Rad22 DNA repair foci that occur in cycling cells. Most of these foci colocalize with the nucleolus, which contains the rDNA repeats. The increased fork pausing at the replication fork barriers in the rDNA repeats in a strain that lacks Rqh1 DNA helicase is further increased by expression of a dominant negative form of Slx1. These data suggest that Slx1-Slx4 cleaves paused replication forks in the rDNA, leading to Rad22-dependent homologous recombination that is used to maintain rDNA copy number.
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Affiliation(s)
- Stéphane Coulon
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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19
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Osman F, Dixon J, Barr AR, Whitby MC. The F-Box DNA helicase Fbh1 prevents Rhp51-dependent recombination without mediator proteins. Mol Cell Biol 2005; 25:8084-96. [PMID: 16135800 PMCID: PMC1234329 DOI: 10.1128/mcb.25.18.8084-8096.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A key step in homologous recombination is the loading of Rad51 onto single-stranded DNA to form a nucleoprotein filament that promotes homologous DNA pairing and strand exchange. Mediator proteins, such as Rad52 and Rad55-Rad57, are thought to aid filament assembly by overcoming an inhibitory effect of the single-stranded-DNA-binding protein replication protein A. Here we show that mediator proteins are also required to enable fission yeast Rad51 (called Rhp51) to function in the presence of the F-box DNA helicase Fbh1. In particular, we show that the critical function of Rad22 (an orthologue of Rad52) in promoting Rhp51-dependent recombination and DNA repair can be mostly circumvented by deleting fbh1. Similarly, the reduced growth/viability and DNA damage sensitivity of an fbh1(-) mutant are variously suppressed by deletion of any one of the mediators Rad22, Rhp55, and Swi5. From these data we propose that Rhp51 action is controlled through an interplay between Fbh1 and the mediator proteins. Colocalization of Fbh1 with Rhp51 damage-induced foci suggests that this interplay occurs at the sites of nucleoprotein filament assembly. Furthermore, analysis of different fbh1 mutant alleles suggests that both the F-box and helicase activities of Fbh1 contribute to controlling Rhp51.
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Affiliation(s)
- Fekret Osman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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20
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de Vries FAT, Zonneveld JBM, van Duijn-Goedhart A, Roodbergen M, Boei J, van Buul PPW, Essers J, van Steeg H, van Zeeland AA, van Benthem J, Pastink A. Inactivation of RAD52 aggravates RAD54 defects in mice but not in Schizosaccharomyces pombe. DNA Repair (Amst) 2005; 4:1121-8. [PMID: 16009599 DOI: 10.1016/j.dnarep.2005.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Revised: 05/12/2005] [Accepted: 06/02/2005] [Indexed: 01/09/2023]
Abstract
RAD52 and RAD54 genes from Saccharomyces cerevisiae are required for double-strand break repair through homologous recombination and show epistatic interactions i.e., single and double mutant strains are equally sensitive to DNA damaging agents. In here we combined mutations in RAD52 and RAD54 homologs in Schizosaccharomyces pombe and mice. The analysis of mutant strains in S. pombe demonstrated nearly identical sensitivities of rhp54, rad22A and rad22B double and triple mutants to X-rays, cis-diamminedichloroplatinum and hydroxyurea. In this respect, the fission yeast homologs of RAD54 and RAD52 closely resemble their counterparts in S. cerevisiae. To verify if inactivation of RAD52 affects the DNA damage sensitivities of RAD54 deficient mice, several endpoints were studied in double mutant mice and in bone marrow cells derived from these animals. Haemopoietic depression in bone marrow and the formation of micronuclei after in vivo exposure to mitomycine C (MMC) was not increased in either single or double mutant mice in comparison to wildtype animals. The induction of sister chromatid exchanges in splenocytes was slightly reduced in the RAD54 mutant. A similar reduction was detected in the double mutant. However, a deficiency of RAD52 exacerbates the MMC survival of RAD54 mutant mice and also has a distinct effect on the survival of bone marrow cells after exposure to ionizing radiation. These findings may be explained by additive defects in HR in the double mutant but may also indicate a more prominent role for single-strand annealing in the absence of Rad54.
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Affiliation(s)
- Femke A T de Vries
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL, Leiden, The Netherlands
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21
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Young JA, Hyppa RW, Smith GR. Conserved and nonconserved proteins for meiotic DNA breakage and repair in yeasts. Genetics 2005; 167:593-605. [PMID: 15238514 PMCID: PMC1470912 DOI: 10.1534/genetics.103.023762] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During meiosis DNA double-strand breaks initiate recombination in the distantly related budding and fission yeasts and perhaps in most eukaryotes. Repair of broken meiotic DNA is essential for formation of viable gametes. We report here distinct but overlapping sets of proteins in these yeasts required for formation and repair of double-strand breaks. Meiotic DNA breakage in Schizosaccharomyces pombe did not require Rad50 or Rad32, although the homologs Rad50 and Mre11 are required in Saccharomyces cerevisiae; these proteins are required for meiotic DNA break repair in both yeasts. DNA breakage required the S. pombe midmeiosis transcription factor Mei4, but the structurally unrelated midmeiosis transcription factor Ndt80 is not required for breakage in S. cerevisiae. Rhp51, Swi5, and Rad22 + Rti1 were required for full levels of DNA repair in S. pombe, as are the related S. cerevisiae proteins Rad51, Sae3, and Rad52. Dmc1 was not required for repair in S. pombe, but its homolog Dmc1 is required in the well-studied strain SK1 of S. cerevisiae. Additional proteins required in one yeast have no obvious homologs in the other yeast. The occurrence of conserved and nonconserved proteins indicates potential diversity in the mechanism of meiotic recombination and divergence of the machinery during the evolution of eukaryotes.
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Affiliation(s)
- Jennifer A Young
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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22
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Hope JC, Maftahi M, Freyer GA. A postsynaptic role for Rhp55/57 that is responsible for cell death in Deltarqh1 mutants following replication arrest in Schizosaccharomyces pombe. Genetics 2005; 170:519-31. [PMID: 15802523 PMCID: PMC1450410 DOI: 10.1534/genetics.104.037598] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Following replication arrest, multiple cellular responses are triggered to maintain genomic integrity. In fission yeast, the RecQ helicase, Rqh1, plays a critical role in this process. This is demonstrated in Deltarqh1 cells that, following treatment with hydroxyurea (HU), undergo an aberrant mitosis leading to cell death. Previous data suggest that Rqh1 functions with homologous recombination (HR) in recovery from replication arrest. We have found that loss of the HR genes rhp55(+) or rhp57(+), but not rhp51(+) or rhp54(+), suppresses the HU sensitivity of Deltarqh1 cells. Much of this suppression requires Rhp51 and Rhp54. In addition, this suppression is partially dependent on swi5(+). In budding yeast, overexpressing Rad51 (the Rhp51 homolog) minimized the need for Rad55/57 (Rhp55/57) in nucleoprotein filament formation. We overexpressed Rhp51 in Schizosaccharomyces pombe and found that it greatly reduced the requirement for Rhp55/57 in recovery from DNA damage. However, overexpressing Rhp51 did not change the Deltarhp55 suppression of the HU sensitivity of Deltarqh1, supporting an Rhp55/57 function during HR independent of nucleoprotein filament formation. These results are consistent with Rqh1 playing a role late in HR following replication arrest and provide evidence for a postsynaptic function for Rhp55/57.
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Affiliation(s)
- Justin C Hope
- Graduate Program in Anatomy and Cell Biology, Department of Anatomy and Cell Biology, Columbia University, New York, NY 10032, USA
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23
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Ferreira MG, Cooper JP. Two modes of DNA double-strand break repair are reciprocally regulated through the fission yeast cell cycle. Genes Dev 2004; 18:2249-54. [PMID: 15371339 PMCID: PMC517518 DOI: 10.1101/gad.315804] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Several considerations suggest that levels of the two major modes of double-strand break (DSB) repair, homologous recombination (HR), and nonhomologous end joining (NHEJ), are regulated through the cell cycle. However, this idea has not been explicitly tested. In the absence of the telomere-binding protein Taz1, fission yeast undergo lethal telomere fusions via NHEJ. These fusions occur only during periods of nitrogen starvation and fail to accumulate during logarithmic growth, when the majority of cells are in G2. We show that G1 arrest is the specific nitrogen starvation-induced event that promotes NHEJ between taz1(-) telomeres. Furthermore, the general levels of NHEJ and HR are reciprocally regulated through the cell cycle, so that NHEJ is 10-fold higher in early G1 than in other cell cycle stages; the reverse is true for HR. Whereas NHEJ is known to be dispensable for survival of DSBs in cycling cells, we find that it is critical for repair and survival of DSBs arising during G1.
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24
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Malik M, Nitiss JL. DNA repair functions that control sensitivity to topoisomerase-targeting drugs. EUKARYOTIC CELL 2004; 3:82-90. [PMID: 14871939 PMCID: PMC329506 DOI: 10.1128/ec.3.1.82-90.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DNA topoisomerases play critical roles in a wide range of cellular processes by altering DNA topology to facilitate replication, transcription, and chromosome segregation. Topoisomerases alter DNA topology by introducing transient DNA strand breaks that involve a covalent protein DNA intermediate. Many agents have been found to prevent the religation of DNA strand breaks induced by the enzymes, thereby converting the enzymes into DNA-damaging agents. Repair of the DNA damage induced by topoisomerases is significant in understanding drug resistance arising following treatment with topoisomerase-targeting drugs. We have used the fission yeast Schizosaccharomyces pombe to identify DNA repair pathways that are important for cell survival following drug treatment. S. pombe strains carrying mutations in genes required for homologous recombination such as rad22A or rad32 (homologues of RAD52 and MRE11) are hypersensitive to drugs targeting either topoisomerase I or topoisomerase II. In contrast to results observed with Saccharomyces cerevisiae, S. pombe strains defective in nucleotide excision repair are also hypersensitive to topoisomerase-targeting agents. The loss of DNA replication or DNA damage checkpoints also sensitizes cells to both topoisomerase I and topoisomerase II inhibitors. Finally, repair genes (such as the S. pombe rad8+ gene) with no obvious homologs in other systems also play important roles in causing sensitivity to topoisomerase drugs. Since the pattern of sensitivity is distinct from that seen with other systems (such as the S. cerevisiae system), our results highlight the usefulness of S. pombe in understanding how cells deal with the unique DNA damage induced by topoisomerases.
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Affiliation(s)
- Mobeen Malik
- Department of Molecular Pharmacology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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25
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Doe CL, Osman F, Dixon J, Whitby MC. DNA repair by a Rad22-Mus81-dependent pathway that is independent of Rhp51. Nucleic Acids Res 2004; 32:5570-81. [PMID: 15486206 PMCID: PMC524275 DOI: 10.1093/nar/gkh853] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In budding yeast most Rad51-dependent and -independent recombination depends on Rad52. In contrast, its homologue in fission yeast, Rad22, was assumed to play a less critical role possibly due to functional redundancy with another Rad52-like protein Rti1. We show here that this is not the case. Rad22 like Rad52 plays a central role in recombination being required for both Rhp51-dependent and -independent events. Having established this we proceed to investigate the involvement of the Mus81-Eme1 endonuclease in these pathways. Mus81 plays a relatively minor role in the Rhp51-dependent repair of DNA damage induced by ultraviolet light. In contrast Mus81 has a key role in the Rad22-dependent (Rhp51-independent) repair of damage induced by camptothecin, hydroxyurea and methyl-methanesulfonate. Furthermore, spontaneous intrachromosomal recombination that gives rise to deletion recombinants is impaired in a mus81 mutant. From these data we propose that a Rad22-Mus81-dependent (Rhp51-independent) pathway is an important mechanism for the repair of DNA damage in fission yeast. Consistent with this we show that in vitro Rad22 can promote strand invasion to form a D-loop that can be cleaved by Mus81.
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Affiliation(s)
- Claudette L Doe
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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26
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Ciudad T, Andaluz E, Steinberg-Neifach O, Lue NF, Gow NAR, Calderone RA, Larriba G. Homologous recombination in Candida albicans: role of CaRad52p in DNA repair, integration of linear DNA fragments and telomere length. Mol Microbiol 2004; 53:1177-94. [PMID: 15306020 DOI: 10.1111/j.1365-2958.2004.04197.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chromosomal rearrangements are common in both clinical isolates and spontaneous mutants of Candida albicans. It appears that many of these rearrangements are caused by translocations around the major sequence repeat (MSR) that is present in all chromosomes except chromosome 3, suggesting that homologous recombination (HR) may play an important role in the survival of this organism. In order to gain information on these processes, we have cloned the homologue of RAD52, which in Saccharomyces cerevisiae is the only gene required for all HR events. CaRAD52 complemented poorly a rad52 mutant of S. cerevisiae. Two null Carad52Delta/Carad52Delta mutants were constructed by sequential deletion of both alleles and two reconstituted strains were obtained by reintegration of the gene. Characterization of these mutants indicated that HR plays an essential role in the repair of DNA lesions caused by both UV light and the radiomimetic compound methyl-methane-sulphonate (MMS), whereas the non-homologous end-joining pathway (NHEJ) is used only in the absence of Rad52p or after extensive DNA damage. Repair by HR is more efficient in exponentially growing than in stationary cells, probably because a larger number of cells are in late S or G2 phases of the cell cycle (and therefore, can use a sister chromatid as a substrate for recombinational repair), whereas stationary phase cells are mainly in G0 or G1, and only can be repaired using the chromosomal homologue. In addition, CaRad52p is absolutely required for the integration of linear DNA with long flanking homologous sequences. Finally, the absence of CaRad52p results in the lengthening of telomeres, even in the presence of an active telomerase, an observation not described in any other organism. This raises the possibility that both telomerase and homologous recombination may function simultaneously at C. albicans telomeres.
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Affiliation(s)
- Toni Ciudad
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
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27
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Nakamura TM, Du LL, Redon C, Russell P. Histone H2A phosphorylation controls Crb2 recruitment at DNA breaks, maintains checkpoint arrest, and influences DNA repair in fission yeast. Mol Cell Biol 2004; 24:6215-30. [PMID: 15226425 PMCID: PMC434244 DOI: 10.1128/mcb.24.14.6215-6230.2004] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Revised: 04/20/2004] [Accepted: 04/26/2004] [Indexed: 11/20/2022] Open
Abstract
Mammalian ATR and ATM checkpoint kinases modulate chromatin structures near DNA breaks by phosphorylating a serine residue in the carboxy-terminal tail SQE motif of histone H2AX. Histone H2A is similarly regulated in Saccharomyces cerevisiae. The phosphorylated forms of H2AX and H2A, known as gamma-H2AX and gamma-H2A, are thought to be important for DNA repair, although their evolutionarily conserved roles are unknown. Here, we investigate gamma-H2A in the fission yeast Schizosaccharomyces pombe. We show that formation of gamma-H2A redundantly requires the ATR/ATM-related kinases Rad3 and Tel1. Mutation of the SQE motif to AQE (H2A-AQE) in the two histone H2A genes caused sensitivity to a wide range of genotoxic agents, increased spontaneous DNA damage, and impaired checkpoint maintenance. The H2A-AQE mutations displayed a striking synergistic interaction with rad22Delta (Rad52 homolog) in ionizing radiation (IR) survival. These phenotypes correlated with defective phosphorylation of the checkpoint proteins Crb2 and Chk1 and a failure to recruit large amounts of Crb2 to damaged DNA. Surprisingly, the H2A-AQE mutations substantially suppressed the IR hypersensitivity of crb2Delta cells by a mechanism that required the RecQ-like DNA helicase Rqh1. We propose that gamma-H2A modulates checkpoint and DNA repair through large-scale recruitment of Crb2 to damaged DNA. This function correlates with evidence that gamma-H2AX regulates recruitment of several BRCA1 carboxyl terminus domain-containing proteins (NBS1, 53BP1, MDC1/NFBD1, and BRCA1) in mammals.
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Affiliation(s)
- Toru M Nakamura
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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28
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Dudás A, Chovanec M. DNA double-strand break repair by homologous recombination. Mutat Res 2004; 566:131-67. [PMID: 15164978 DOI: 10.1016/j.mrrev.2003.07.001] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2003] [Revised: 07/29/2003] [Accepted: 07/30/2003] [Indexed: 01/06/2023]
Abstract
DNA double-strand breaks (DSB) are presumed to be the most deleterious DNA lesions as they disrupt both DNA strands. Homologous recombination (HR), single-strand annealing, and non-homologous end-joining are considered to be the pathways for repairing DSB. In this review, we focus on DSB repair by HR. The proteins involved in this process as well as the interactions among them are summarized and characterized. The main emphasis is on eukaryotic cells, particularly the budding yeast Saccharomyces cerevisiae and mammals. Only the RAD52 epistasis group proteins are included.
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Affiliation(s)
- Andrej Dudás
- Laboratory of Molecular Genetics, Cancer Research Institute, Slovak Academy of Sciences, Vlárska 7, 833 91 Bratislava 37, Slovak Republic
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29
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van Waardenburg RC, de Jong LA, van Delft F, van Eijndhoven MA, Bohlander M, Bjornsti MA, Brouwer J, Schellens JH. Homologous recombination is a highly conserved determinant of the synergistic cytotoxicity between cisplatin and DNA topoisomerase I poisons. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.393.3.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Phase I and II clinical trails are currently investigating the antitumor activity of cisplatin and camptothecins (CPTs; DNA topoisomerase I poisons), based on the dramatic synergistic cytotoxicity of these agents in some preclinical models. However, the mechanistic basis for this synergism is poorly understood. By exploiting the evolutionary conservation of DNA repair pathways from genetically tractable organisms such as budding and fission yeasts to mammalian cells, we demonstrate that the synergism of CPT and cisplatin requires homologous recombination. In yeast and mammalian cell lines defective for RAD52 and XRCC2/3, respectively, the combination of these agents proved antagonistic, while greater than additive activity was evident in isogenic wild-type cells. Homologous recombination appears to mediate a similar interaction of X-rays and CPT, but antagonizes the synergism of cytarabine (Ara-C) with CPT. These findings suggest that homologous recombination comprises an evolutionarily conserved determinant of cellular sensitivity when CPTs are used in combination with other therapeutics.
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Affiliation(s)
| | - Laurina A. de Jong
- 1Department of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Foke van Delft
- 1Department of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Melanie Bohlander
- 1Department of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Mary-Ann Bjornsti
- 3Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN
| | - Jaap Brouwer
- 2Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Jan H.M. Schellens
- 1Department of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- 4Faculty Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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30
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Du LL, Nakamura TM, Moser BA, Russell P. Retention but not recruitment of Crb2 at double-strand breaks requires Rad1 and Rad3 complexes. Mol Cell Biol 2003; 23:6150-8. [PMID: 12917337 PMCID: PMC180945 DOI: 10.1128/mcb.23.17.6150-6158.2003] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The fission yeast checkpoint protein Crb2, related to budding yeast Rad9 and human 53BP1 and BRCA1, has been suggested to act as an adapter protein facilitating the phosphorylation of specific substrates by Rad3-Rad26 kinase. To further understand its role in checkpoint signaling, we examined its localization in live cells by using fluorescence microscopy. In response to DNA damage, Crb2 localizes to distinct nuclear foci, which represent sites of DNA double-strand breaks (DSBs). Crb2 colocalizes with Rad22 at persistent foci, suggesting that Crb2 is retained at sites of DNA damage during repair. Damage-induced Crb2 foci still form in cells defective in Rad1, Rad3, and Rad17 complexes, but these foci do not persist as long as in wild-type cells. Our results suggest that Crb2 functions at the sites of DNA damage, and its regulated persistent localization at damage sites may be involved in facilitating DNA repair and/or maintaining the checkpoint arrest while DNA repair is under way.
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Affiliation(s)
- Li-Lin Du
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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31
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Prudden J, Evans JS, Hussey SP, Deans B, O’Neill P, Thacker J, Humphrey T. Pathway utilization in response to a site-specific DNA double-strand break in fission yeast. EMBO J 2003; 22:1419-30. [PMID: 12628934 PMCID: PMC151045 DOI: 10.1093/emboj/cdg119] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have examined the genetic requirements for efficient repair of a site-specific DNA double-strand break (DSB) in Schizosaccharomyces pombe. Tech nology was developed in which a unique DSB could be generated in a non-essential minichromosome, Ch(16), using the Saccharomyces cerevisiae HO-endonuclease and its target site, MATa. DSB repair in this context was predominantly through interchromosomal gene conversion. We found that the homologous recombination (HR) genes rhp51(+), rad22A(+), rad32(+) and the nucleotide excision repair gene rad16(+) were required for efficient interchromosomal gene conversion. Further, DSB-induced cell cycle delay and efficient HR required the DNA integrity checkpoint gene rad3(+). Rhp55 was required for interchromosomal gene conversion; however, an alternative DSB repair mechanism was used in an rhp55Delta background involving ku70(+) and rhp51(+). Surprisingly, DSB-induced minichromosome loss was significantly reduced in ku70Delta and lig4Delta non-homologous end joining (NHEJ) mutant backgrounds compared with wild type. Furthermore, roles for Ku70 and Lig4 were identified in suppressing DSB-induced chromosomal rearrangements associated with gene conversion. These findings are consistent with both competitive and cooperative interactions between components of the HR and NHEJ pathways.
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Affiliation(s)
| | | | | | | | | | | | - Tim Humphrey
- MRC Radiation and Genome Stability Unit, Harwell, Didcot, Oxon OX11 0RD, UK
Corresponding author e-mail:
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Symington LS. Role of RAD52 epistasis group genes in homologous recombination and double-strand break repair. Microbiol Mol Biol Rev 2002; 66:630-70, table of contents. [PMID: 12456786 PMCID: PMC134659 DOI: 10.1128/mmbr.66.4.630-670.2002] [Citation(s) in RCA: 790] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The process of homologous recombination is a major DNA repair pathway that operates on DNA double-strand breaks, and possibly other kinds of DNA lesions, to promote error-free repair. Central to the process of homologous recombination are the RAD52 group genes (RAD50, RAD51, RAD52, RAD54, RDH54/TID1, RAD55, RAD57, RAD59, MRE11, and XRS2), most of which were identified by their requirement for the repair of ionizing-radiation-induced DNA damage in Saccharomyces cerevisiae. The Rad52 group proteins are highly conserved among eukaryotes, and Rad51, Mre11, and Rad50 are also conserved in prokaryotes and archaea. Recent studies showing defects in homologous recombination and double-strand break repair in several human cancer-prone syndromes have emphasized the importance of this repair pathway in maintaining genome integrity. Although sensitivity to ionizing radiation is a universal feature of rad52 group mutants, the mutants show considerable heterogeneity in different assays for recombinational repair of double-strand breaks and spontaneous mitotic recombination. Herein, I provide an overview of recent biochemical and structural analyses of the Rad52 group proteins and discuss how this information can be incorporated into genetic studies of recombination.
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Affiliation(s)
- Lorraine S Symington
- Department of Microbiology and Institute of Cancer Research, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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Segurado M, Gómez M, Antequera F. Increased recombination intermediates and homologous integration hot spots at DNA replication origins. Mol Cell 2002; 10:907-16. [PMID: 12419233 DOI: 10.1016/s1097-2765(02)00684-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have studied the relationship between DNA replication and recombination in Schizosaccharomyces pombe using two-dimensional gel electrophoresis and functional analysis. Our results indicate that the activation of replication origins (ORIs) during the mitotic cell cycle is associated with the generation of joint DNA molecules between sister chromatids. The frequency of integration by homologous recombination was up to 50-fold higher than the genomic average within a narrow window overlapping the ars1 replication initiation site. The S. pombe rad22Delta, rhp51Delta, and rhp54Delta mutants, deficient in mitotic recombination, activate ORIs very inefficiently and accumulate abnormal replication intermediates. These results focus on the general link between replication and recombination previously found in several systems and suggest a role for recombination in the initiation of eukaryotic DNA replication.
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Affiliation(s)
- Mónica Segurado
- Instituto de Microbiología Bioquímica, CSIC/Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain
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Kim WJ, Park EJ, Lee H, Seong RH, Park SD. Physical interaction between recombinational proteins Rhp51 and Rad22 in Schizosaccharomyces pombe. J Biol Chem 2002; 277:30264-70. [PMID: 12050150 DOI: 10.1074/jbc.m202517200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In eukaryotes, Rad51 and Rad52 are two key components of homologous recombination and recombinational repair. These two proteins interact with each other. Here we investigated the role of interaction between Rhp51 and Rad22, the fission yeast homologs of Rad51 and Rad52, respectively, on the function of each protein. We identified a direct association between the two proteins and their self-interactions both in vivo and in vitro. We also determined the binding domains of each protein that mediate these interactions. To characterize the role of Rhp51-Rad22 interaction, we used random mutagenesis to identify the mutants Rhp51 and Rad22, which cannot interact each other. Interestingly, we found that mutant Rhp51 protein, which cannot interact with either Rad22 or Rti1 (G282D), lost its DNA repair ability. In contrast, mutant Rad22 proteins, which cannot specifically bind to Rhp51 (S379L and P381L), maintained their DNA repair ability. These results suggest that the interaction between Rhp51 and Rad22 is crucial for the recombinational repair function of Rhp51. However, the significance of this interaction on the function of Rad22 remains to be characterized further.
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Affiliation(s)
- Woo Jae Kim
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea
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Kagawa W, Kurumizaka H, Ishitani R, Fukai S, Nureki O, Shibata T, Yokoyama S. Crystal structure of the homologous-pairing domain from the human Rad52 recombinase in the undecameric form. Mol Cell 2002; 10:359-71. [PMID: 12191481 DOI: 10.1016/s1097-2765(02)00587-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The human Rad52 protein forms a heptameric ring that catalyzes homologous pairing. The N-terminal half of Rad52 is the catalytic domain for homologous pairing, and the ring formed by the domain fragment was reported to be approximately decameric. Splicing variants of Rad52 and a yeast homolog (Rad59) are composed mostly of this domain. In this study, we determined the crystal structure of the homologous-pairing domain of human Rad52 and revealed that the domain forms an undecameric ring. Each monomer has a beta-beta-beta-alpha fold, which consists of highly conserved amino acid residues among Rad52 homologs. A mutational analysis revealed that the amino acid residues located between the beta-beta-beta-alpha fold and the characteristic hairpin loop are essential for ssDNA and dsDNA binding.
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Affiliation(s)
- Wataru Kagawa
- RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Japan
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van den Bosch M, Lohman PHM, Pastink A. DNA double-strand break repair by homologous recombination. Biol Chem 2002; 383:873-92. [PMID: 12222678 DOI: 10.1515/bc.2002.095] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The induction of double-strand breaks (DSBs) in DNA by exposure to DNA damaging agents, or as intermediates in normal cellular processes, constitutes a severe threat for the integrity of the genome. If not properly repaired, DSBs may result in chromosomal aberrations, which, in turn, can lead to cell death or to uncontrolled cell growth. To maintain the integrity of the genome, multiple pathways for the repair of DSBs have evolved during evolution: homologous recombination (HR), non-homologous end joining (NHEJ) and single-strand annealing (SSA). HR has the potential to lead to accurate repair of DSBs, whereas NHEJ and SSA are essentially mutagenic. In yeast, DSBs are primarily repaired via high-fidelity repair of DSBs mediated by HR, whereas in higher eukaryotes, both HR and NHEJ are important. In this review, we focus on the functional conservation of HR from fungi to mammals and on the role of the individual proteins in this process.
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Affiliation(s)
- Michael van den Bosch
- Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Center, The Netherlands
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van den Bosch M, Zonneveld JBM, Vreeken K, de Vries FAT, Lohman PHM, Pastink A. Differential expression and requirements for Schizosaccharomyces pombe RAD52 homologs in DNA repair and recombination. Nucleic Acids Res 2002; 30:1316-24. [PMID: 11884628 PMCID: PMC101351 DOI: 10.1093/nar/30.6.1316] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In fission yeast two RAD52 homologs have been identified, rad22A(+) and rad22B(+). Two-hybrid experiments and GST pull-down assays revealed physical interaction between Rad22A and Rad22B, which is dependent on the N-terminal regions. Interaction with Rhp51 is dependent on the C-terminal parts of either protein. Both Rad22A and Rad22B also interact with RPA. The expression of rad22B(+) in mitotically dividing cells is very low in comparison with rad22A(+) but is strongly enhanced after induction of meiosis, in contrast to rad22A(+). Rad22B mutant cells are not hypersensitive to DNA-damaging agents (X-rays, UV and cisplatin) and display normal levels of recombination. In these respects the Schizosaccharomyces pombe rad22B mutant resembles the weak phenotype of vertebrate cells deficient for RAD52. Mutation of rad22A(+) leads to severe sensitivity to DNA-damaging agents and to defects in recombination. In a rad22Arad22B double mutant a further increase in sensitivity to DNA-damaging agents and additional mitotic recombination defects were observed. The data presented here indicate that Rad22A and Rad22B have overlapping roles in repair and recombination, although specialized functions for each protein cannot be excluded.
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Affiliation(s)
- Michael van den Bosch
- MGC Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
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Ho JC, Warr NJ, Shimizu H, Watts FZ. SUMO modification of Rad22, the Schizosaccharomyces pombe homologue of the recombination protein Rad52. Nucleic Acids Res 2001; 29:4179-86. [PMID: 11600706 PMCID: PMC60211 DOI: 10.1093/nar/29.20.4179] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Schizosaccharomyces pombe rad31 and hus5 genes are required for the DNA damage response, as mutants defective in these genes are sensitive to DNA damaging agents, such as UV and ionising radiation and to the DNA synthesis inhibitor hydroxyurea (HU). Sequence analysis has suggested that rad31 and hus5 encode components of the Pmt3 (SUMO) modification process in S.pombe. We show here that the rad31 null and hus5.62 mutants display reduced levels of Pmt3 modification. We have initiated a search for proteins required for the DNA damage response, which may be modified by Pmt3 and have identified Rad22, the fission yeast homologue of the recombination protein Rad52. Purification of myc + His-tagged Rad22 protein from cells expressing HA-tagged Pmt3 identifies an 83 kDa species which cross-reacts with anti-HA antisera. We show here that Rad22 interacts with Rhp51 and Rpa70 (the fission yeast homologues of Rad51 and the large subunit of RPA, respectively), but that neither of these proteins appears to be responsible for the 83 kDa species. The 83 kDa species is observed when extracts are prepared under both native and denaturing conditions, and is also observed when myc + His-tagged Rad22 and Pmt3 are expressed at wild type levels, suggesting that Rad22 is modified by Pmt3 in vivo. We have established an S.pombe in vitro Pmt3 modification system and have shown that Rad22 and Rhp51 are modified in vitro, but that Rpa70 is not.
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Affiliation(s)
- J C Ho
- Department of Biochemistry, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
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Davis AP, Symington LS. The yeast recombinational repair protein Rad59 interacts with Rad52 and stimulates single-strand annealing. Genetics 2001; 159:515-25. [PMID: 11606529 PMCID: PMC1461847 DOI: 10.1093/genetics/159.2.515] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The yeast RAD52 gene is essential for homology-dependent repair of DNA double-strand breaks. In vitro, Rad52 binds to single- and double-stranded DNA and promotes annealing of complementary single-stranded DNA. Genetic studies indicate that the Rad52 and Rad59 proteins act in the same recombination pathway either as a complex or through overlapping functions. Here we demonstrate physical interaction between Rad52 and Rad59 using the yeast two-hybrid system and co-immunoprecipitation from yeast extracts. Purified Rad59 efficiently anneals complementary oligonucleotides and is able to overcome the inhibition to annealing imposed by replication protein A (RPA). Although Rad59 has strand-annealing activity by itself in vitro, this activity is insufficient to promote strand annealing in vivo in the absence of Rad52. The rfa1-D288Y allele partially suppresses the in vivo strand-annealing defect of rad52 mutants, but this is independent of RAD59. These results suggest that in vivo Rad59 is unable to compete with RPA for single-stranded DNA and therefore is unable to promote single-strand annealing. Instead, Rad59 appears to augment the activity of Rad52 in strand annealing.
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Affiliation(s)
- A P Davis
- Department of Microbiology and Institute of Cancer Research, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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Tsutsui Y, Khasanov FK, Shinagawa H, Iwasaki H, Bashkirov VI. Multiple interactions among the components of the recombinational DNA repair system in Schizosaccharomyces pombe. Genetics 2001; 159:91-105. [PMID: 11560889 PMCID: PMC1461803 DOI: 10.1093/genetics/159.1.91] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schizosaccharomyces pombe Rhp55 and Rhp57 are RecA-like proteins involved in double-strand break (DSB) repair. Here we demonstrate that Rhp55 and Rhp57 proteins strongly interact in vivo, similar to Saccharomyces cerevisiae Rad55p and Rad57p. Mutations in the conserved ATP-binding/hydrolysis folds of both the Rhp55 and Rhp57 proteins impaired their function in DNA repair but not in cell proliferation. However, when combined, ATPase fold mutations in Rhp55p and Rhp57p resulted in severe defects of both functions, characteristic of the deletion mutants. Yeast two-hybrid analysis also revealed other multiple in vivo interactions among S. pombe proteins involved in recombinational DNA repair. Similar to S. cerevisiae Rad51p-Rad54p, S. pombe Rhp51p and Rhp54p were found to interact. Both putative Rad52 homologs in S. pombe, Rad22p and Rti1p, were found to interact with the C-terminal region of Rhp51 protein. Moreover, Rad22p and Rti1p exhibited mutual, as well as self-, interactions. In contrast to the S. cerevisiae interacting pair Rad51p-Rad55p, S. pombe Rhp51 protein strongly interacted with Rhp57 but not with Rhp55 protein. In addition, the Rti1 and Rad22 proteins were found to form a complex with the large subunit of S. pombe RPA. Our data provide compelling evidence that most, but not all, of the protein-protein interactions found in S. cerevisiae DSB repair are evolutionarily conserved.
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Affiliation(s)
- Y Tsutsui
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
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Lisby M, Rothstein R, Mortensen UH. Rad52 forms DNA repair and recombination centers during S phase. Proc Natl Acad Sci U S A 2001; 98:8276-82. [PMID: 11459964 PMCID: PMC37432 DOI: 10.1073/pnas.121006298] [Citation(s) in RCA: 354] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maintenance of genomic integrity and stable transmission of genetic information depend on a number of DNA repair processes. Failure to faithfully perform these processes can result in genetic alterations and subsequent development of cancer and other genetic diseases. In the eukaryote Saccharomyces cerevisiae, homologous recombination is the major pathway for repairing DNA double-strand breaks. The key role played by Rad52 in this pathway has been attributed to its ability to seek out and mediate annealing of homologous DNA strands. In this study, we find that S. cerevisiae Rad52 fused to green fluorescent protein (GFP) is fully functional in DNA repair and recombination. After induction of DNA double-strand breaks by gamma-irradiation, meiosis, or the HO endonuclease, Rad52-GFP relocalizes from a diffuse nuclear distribution to distinct foci. Interestingly, Rad52 foci are formed almost exclusively during the S phase of mitotic cells, consistent with coordination between recombinational repair and DNA replication. This notion is further strengthened by the dramatic increase in the frequency of Rad52 focus formation observed in a pol12-100 replication mutant and a mec1 DNA damage checkpoint mutant. Furthermore, our data indicate that each Rad52 focus represents a center of recombinational repair capable of processing multiple DNA lesions.
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Affiliation(s)
- M Lisby
- Department of Genetics and Development, Columbia University, College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032-2704, USA
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Current Awareness. Yeast 2001. [DOI: 10.1002/yea.686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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