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Hengel SR, Oppenheimer KG, Smith CM, Schaich MA, Rein HL, Martino J, Darrah KE, Witham M, Ezekwenna OC, Burton KR, Van Houten B, Spies M, Bernstein KA. The human Shu complex promotes RAD51 activity by modulating RPA dynamics on ssDNA. Nat Commun 2024; 15:7197. [PMID: 39169038 PMCID: PMC11339404 DOI: 10.1038/s41467-024-51595-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/09/2024] [Indexed: 08/23/2024] Open
Abstract
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1, SWS1, and SPIDR. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single-molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter Shu complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
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Affiliation(s)
- Sarah R Hengel
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA.
- Tufts University, Department of Biology, Medford, MA, USA.
| | - Katherine G Oppenheimer
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Chelsea M Smith
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
- University of North Carolina at Chapel Hill, Department of Pathology and Laboratory Medicine, Chapel Hill, NC, USA
| | - Matthew A Schaich
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Hayley L Rein
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Julieta Martino
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
- GeneDx, Gaithersburg, MD, USA
| | - Kristie E Darrah
- University of Pennsylvania School of Medicine, Penn Center for Genome Integrity, Department of Biochemistry and Biophysics, 421 Curie Boulevard, Philadelphia, PA, USA
| | - Maggie Witham
- Tufts University, Department of Biology, Medford, MA, USA
| | | | - Kyle R Burton
- Tufts University, Department of Biology, Medford, MA, USA
| | - Bennett Van Houten
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA
| | - Maria Spies
- University of Iowa, Department of Biochemistry and Molecular Biology, Iowa City, IA, USA
| | - Kara A Bernstein
- University of Pittsburgh, School of Medicine, Department of Pharmacology and Chemical Biology, UPMC-Hillman Cancer Center, Pittsburgh, PA, USA.
- University of Pennsylvania School of Medicine, Penn Center for Genome Integrity, Department of Biochemistry and Biophysics, 421 Curie Boulevard, Philadelphia, PA, USA.
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2
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Hengel SR, Oppenheimer K, Smith C, Schaich MA, Rein HL, Martino J, Darrah K, Ezekwenna O, Burton K, Van Houten B, Spies M, Bernstein KA. The human Shu complex promotes RAD51 activity by modulating RPA dynamics on ssDNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580393. [PMID: 38405734 PMCID: PMC10888808 DOI: 10.1101/2024.02.14.580393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1 and SWS1. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter SWS1 complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
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3
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Tire B, Talibova G, Ozturk S. The crosstalk between telomeres and DNA repair mechanisms: an overview to mammalian somatic cells, germ cells, and preimplantation embryos. J Assist Reprod Genet 2024; 41:277-291. [PMID: 38165506 PMCID: PMC10894803 DOI: 10.1007/s10815-023-03008-2] [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: 07/10/2023] [Accepted: 12/12/2023] [Indexed: 01/03/2024] Open
Abstract
Telomeres are located at the ends of linear chromosomes and play a critical role in maintaining genomic stability by preventing premature activation of DNA repair mechanisms. Because of exposure to various genotoxic agents, telomeres can undergo shortening and genetic changes. In mammalian cells, the basic DNA repair mechanisms, including base excision repair, nucleotide excision repair, double-strand break repair, and mismatch repair, function in repairing potential damages in telomeres. If these damages are not repaired correctly in time, the unfavorable results such as apoptosis, cell cycle arrest, and cancerous transition may occur. During lifespan, mammalian somatic cells, male and female germ cells, and preimplantation embryos experience a number of telomeric damages. Herein, we comprehensively reviewed the crosstalk between telomeres and the DNA repair mechanisms in the somatic cells, germ cells, and embryos. Infertility development resulting from possible defects in this crosstalk is also discussed in the light of existing studies.
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Affiliation(s)
- Betul Tire
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey
| | - Gunel Talibova
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey
| | - Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Campus, 07070, Antalya, Turkey.
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4
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Guh CL, Lei KH, Chen YA, Jiang YZ, Chang HY, Liaw H, Li HW, Yen HY, Chi P. RAD51 paralogs synergize with RAD51 to protect reversed forks from cellular nucleases. Nucleic Acids Res 2023; 51:11717-11731. [PMID: 37843130 PMCID: PMC10681713 DOI: 10.1093/nar/gkad856] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 09/12/2023] [Accepted: 09/23/2023] [Indexed: 10/17/2023] Open
Abstract
Fork reversal is a conserved mechanism to prevent stalled replication forks from collapsing. Formation and protection of reversed forks are two crucial steps in ensuring fork integrity and stability. Five RAD51 paralogs, namely, RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3, which share sequence and structural similarity to the recombinase RAD51, play poorly defined mechanistic roles in these processes. Here, using purified BCDX2 (RAD51BCD-XRCC2) and CX3 (RAD51C-XRCC3) complexes and in vitro reconstituted biochemical systems, we mechanistically dissect their functions in forming and protecting reversed forks. We show that both RAD51 paralog complexes lack fork reversal activities. Whereas CX3 exhibits modest fork protection activity, BCDX2 significantly synergizes with RAD51 to protect DNA against attack by the nucleases MRE11 and EXO1. DNA protection is contingent upon the ability of RAD51 to form a functional nucleoprotein filament on DNA. Collectively, our results provide evidence for a hitherto unknown function of RAD51 paralogs in synergizing with RAD51 nucleoprotein filament to prevent degradation of stressed replication forks.
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Affiliation(s)
- Chia-Lun Guh
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Kai-Hang Lei
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Yi-An Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yi-Zhen Jiang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Hao-Yen Chang
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Hungjiun Liaw
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Hsin-Yung Yen
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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5
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Anwaar A, Varma AK, Baruah R. In Silico-Based Structural Evaluation to Categorize the Pathogenicity of Mutations Identified in the RAD Class of Proteins. ACS OMEGA 2023; 8:10266-10277. [PMID: 36969410 PMCID: PMC10034773 DOI: 10.1021/acsomega.2c07802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
RAD genes, known as double-strand break repair proteins, play a major role in maintaining the genomic integrity of a cell by carrying out essential DNA repair functions via double-strand break repair pathways. Mutations in the RAD class of proteins show high susceptibility to breast and ovarian cancers; however, adequate research on the mutations identified in these genes has not been extensively reported for their deleterious effects. Changes in the folding pattern of RAD proteins play an important role in protein-protein interactions and also functions. Missense mutations identified from four cancer databases, cBioPortal, COSMIC, ClinVar, and gnomAD, cause aberrant conformations, which may lead to faulty DNA repair mechanisms. It is therefore necessary to evaluate the effects of pathogenic mutations of RAD proteins and their subsequent role in breast and ovarian cancers. In this study, we have used eight computational prediction servers to analyze pathogenic mutations and understand their effects on the protein structure and function. A total of 5122 missense mutations were identified from four different cancer databases, of which 1165 were predicted to be pathogenic using at least five pathogenicity prediction servers. These mutations were characterized as high-risk mutations based on their location in the conserved domains and subsequently subjected to structural stability characterization. The mutations included in the present study were selected from clinically relevant mutants in breast cancer pedigrees. Comparative folding patterns and intra-atomic interaction results showed alterations in the structural behavior of RAD proteins, specifically RAD51C triggered by mutations G125V and L138F and RAD51D triggered by mutations S207L and E233G.
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Affiliation(s)
- Aaliya Anwaar
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
| | - Ashok K. Varma
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
- Homi
Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra, India
| | - Reshita Baruah
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
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6
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RAD51 and RAD51B Play Diverse Roles in the Repair of DNA Double Strand Breaks in Physcomitrium patens. Genes (Basel) 2023; 14:genes14020305. [PMID: 36833232 PMCID: PMC9956106 DOI: 10.3390/genes14020305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
RAD51 is involved in finding and invading homologous DNA sequences for accurate homologous recombination (HR). Its paralogs have evolved to regulate and promote RAD51 functions. The efficient gene targeting and high HR rates are unique in plants only in the moss Physcomitrium patens (P. patens). In addition to two functionally equivalent RAD51 genes (RAD1-1 and RAD51-2), other RAD51 paralogues were also identified in P. patens. For elucidation of RAD51's involvement during DSB repair, two knockout lines were constructed, one mutated in both RAD51 genes (Pprad51-1-2) and the second with mutated RAD51B gene (Pprad51B). Both lines are equally hypersensitive to bleomycin, in contrast to their very different DSB repair efficiency. Whereas DSB repair in Pprad51-1-2 is even faster than in WT, in Pprad51B, it is slow, particularly during the second phase of repair kinetic. We interpret these results as PpRAD51-1 and -2 being true functional homologs of ancestral RAD51 involved in the homology search during HR. Absence of RAD51 redirects DSB repair to the fast NHEJ pathway and leads to a reduced 5S and 18S rDNA copy number. The exact role of the RAD51B paralog remains unclear, though it is important in damage recognition and orchestrating HR response.
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Li Z, Wang B, Luo W, Xu Y, Wang J, Xue Z, Niu Y, Cheng Z, Ge S, Zhang W, Zhang J, Li Q, Chong K. Natural variation of codon repeats in COLD11 endows rice with chilling resilience. SCIENCE ADVANCES 2023; 9:eabq5506. [PMID: 36608134 PMCID: PMC9821855 DOI: 10.1126/sciadv.abq5506] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 12/06/2022] [Indexed: 06/07/2023]
Abstract
Abnormal temperature caused by global climate change threatens the rice production. Defense signaling network for chilling has been uncovered in plants. However, less is known about repairing DNA damage produced from overwhelmed defense and its evolution during domestication. Here, we genetically identified a major QTL, COLD11, using the data-merging genome-wide association study based on an algorithm combining polarized data from two subspecies, indica and japonica, into one system. Rice loss-of-function mutations of COLD11 caused reduced chilling tolerance. Genome evolution analysis of representative rice germplasms suggested that numbers of GCG sequence repeats in the first exon of COLD11 were subjected to strong domestication selection during the northern expansion of rice planting. The repeat numbers affected the biochemical activity of DNA repair protein COLD11/RAD51A1 in renovating DNA damage under chilling stress. Our findings highlight a potential way to finely manipulate key genes in rice genome and effectively improve chilling tolerance through molecular designing.
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Affiliation(s)
- Zhitao Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Luo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunyuan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinjuan Wang
- School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, 100181, China
| | - Zhihui Xue
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yuda Niu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhukuan Cheng
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Song Ge
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Wei Zhang
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
| | - Jingyu Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qizhai Li
- University of Chinese Academy of Sciences, Beijing 100049, China
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Sanoguera-Miralles L, Valenzuela-Palomo A, Bueno-Martínez E, Llovet P, Díez-Gómez B, Caloca MJ, Pérez-Segura P, Fraile-Bethencourt E, Colmena M, Carvalho S, Allen J, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. Comprehensive Functional Characterization and Clinical Interpretation of 20 Splice-Site Variants of the RAD51C Gene. Cancers (Basel) 2020; 12:E3771. [PMID: 33333735 PMCID: PMC7765170 DOI: 10.3390/cancers12123771] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary breast and/or ovarian cancer is a highly heterogeneous disease with more than 10 known disease-associated genes. In the framework of the BRIDGES project (Breast Cancer Risk after Diagnostic Gene Sequencing), the RAD51C gene has been sequenced in 60,466 breast cancer patients and 53,461 controls. We aimed at functionally characterizing all the identified genetic variants that are predicted to disrupt the splicing process. Forty RAD51C variants of the intron-exon boundaries were bioinformatically analyzed, 20 of which were selected for splicing functional assays. To test them, a splicing reporter minigene with exons 2 to 8 was designed and constructed. This minigene generated a full-length transcript of the expected size (1062 nucleotides), sequence, and structure (Vector exon V1- RAD51C exons_2-8- Vector exon V2). The 20 candidate variants were genetically engineered into the wild type minigene and functionally assayed in MCF-7 cells. Nineteen variants (95%) impaired splicing, while 18 of them produced severe splicing anomalies. At least 35 transcripts were generated by the mutant minigenes: 16 protein-truncating, 6 in-frame, and 13 minor uncharacterized isoforms. According to ACMG/AMP-based standards, 15 variants could be classified as pathogenic or likely pathogenic variants: c.404G > A, c.405-6T > A, c.571 + 4A > G, c.571 + 5G > A, c.572-1G > T, c.705G > T, c.706-2A > C, c.706-2A > G, c.837 + 2T > C, c.905-3C > G, c.905-2A > C, c.905-2_905-1del, c.965 + 5G > A, c.1026 + 5_1026 + 7del, and c.1026 + 5G > T.
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Affiliation(s)
- Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Patricia Llovet
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - María José Caloca
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain;
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
- Knight Cancer Research Building, 2720 S Moody Ave, Portland, OR 97201, USA
| | - Marta Colmena
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Douglas F. Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Peter Devilee
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Maaike P. G. Vreeswijk
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
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9
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Zhang F, Shen Y, Miao C, Cao Y, Shi W, Du G, Tang D, Li Y, Luo Q, Cheng Z. OsRAD51D promotes homologous pairing and recombination by preventing nonhomologous interactions in rice meiosis. THE NEW PHYTOLOGIST 2020; 227:824-839. [PMID: 32275774 DOI: 10.1111/nph.16595] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
Homologous recombination is carefully orchestrated to maintain genome integrity. RAD51D has been previously shown to be essential for double-strand break repair in mammalian somatic cells. However, the function of RAD51D during meiosis is largely unknown. Here, through detailed analyses of Osrad51d single and double mutants, we pinpoint the specific function of OsRAD51D in coordinating homologous pairing and recombination by preventing nonhomologous interactions during meiosis. OsRAD51D is associated with telomeres in both meiocytes and somatic cells. Loss of OsRAD51D leads to significant induction of nonhomologous pairing and chromosome entanglements, suggesting its role in suppressing nonhomologous interactions. The failed localization of OsRAD51 and OsDMC1 in Osrad51d, together with the genetic analysis of Osrad51d Osdmc1a Osdmc1b, indicates that OsRAD51D acts at a very early stage of homologous recombination. Observations from the Osrad51d pair1 and Osrad51d ku70 double mutants further demonstrate that nonhomologous interactions require double-strand break formation but do not depend on the KU70-mediated repair pathway. Moreover, the interplay between OsRAD51D and OsRAD51C indicates both conservation and divergence of their functions in meiosis. Altogether, this work reveals that OsRAD51D plays an essential role in the inhibition of nonhomologous connections, thus guaranteeing faithful pairing and recombination during meiosis.
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Affiliation(s)
- Fanfan Zhang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yi Shen
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Chunbo Miao
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yiwei Cao
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Wenqing Shi
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Guijie Du
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Ding Tang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yafei Li
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
| | - Qiong Luo
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Ministry of Education Key Laboratory of Agriculture Biodiversity for Plant Disease Management, Yunnan Agricultural University, Kunming, 650201, China
| | - Zhukuan Cheng
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101, Beijing, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou, 225009, China
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10
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Sequential role of RAD51 paralog complexes in replication fork remodeling and restart. Nat Commun 2020; 11:3531. [PMID: 32669601 PMCID: PMC7363682 DOI: 10.1038/s41467-020-17324-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 06/16/2020] [Indexed: 12/19/2022] Open
Abstract
Homologous recombination (HR) factors were recently implicated in DNA replication fork remodeling and protection. While maintaining genome stability, HR-mediated fork remodeling promotes cancer chemoresistance, by as-yet elusive mechanisms. Five HR cofactors – the RAD51 paralogs RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3 – recently emerged as crucial tumor suppressors. Albeit extensively characterized in DNA repair, their role in replication has not been addressed systematically. Here, we identify all RAD51 paralogs while screening for modulators of RAD51 recombinase upon replication stress. Single-molecule analysis of fork progression and architecture in isogenic cellular systems shows that the BCDX2 subcomplex restrains fork progression upon stress, promoting fork reversal. Accordingly, BCDX2 primes unscheduled degradation of reversed forks in BRCA2-defective cells, boosting genomic instability. Conversely, the CX3 subcomplex is dispensable for fork reversal, but mediates efficient restart of reversed forks. We propose that RAD51 paralogs sequentially orchestrate clinically relevant transactions at replication forks, cooperatively promoting fork remodeling and restart. Replication stress has been associated with transient remodelling of replication intermediates into reversed forks, followed by efficient fork restart. Here the authors systematically analyse the role of RAD51 paralogs in these transactions, providing insights on the mechanistic role of different complexes of these proteins.
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11
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Sun Y, McCorvie TJ, Yates LA, Zhang X. Structural basis of homologous recombination. Cell Mol Life Sci 2020; 77:3-18. [PMID: 31748913 PMCID: PMC6957567 DOI: 10.1007/s00018-019-03365-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/10/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022]
Abstract
Homologous recombination (HR) is a pathway to faithfully repair DNA double-strand breaks (DSBs). At the core of this pathway is a DNA recombinase, which, as a nucleoprotein filament on ssDNA, pairs with homologous DNA as a template to repair the damaged site. In eukaryotes Rad51 is the recombinase capable of carrying out essential steps including strand invasion, homology search on the sister chromatid and strand exchange. Importantly, a tightly regulated process involving many protein factors has evolved to ensure proper localisation of this DNA repair machinery and its correct timing within the cell cycle. Dysregulation of any of the proteins involved can result in unchecked DNA damage, leading to uncontrolled cell division and cancer. Indeed, many are tumour suppressors and are key targets in the development of new cancer therapies. Over the past 40 years, our structural and mechanistic understanding of homologous recombination has steadily increased with notable recent advancements due to the advances in single particle cryo electron microscopy. These have resulted in higher resolution structural models of the signalling proteins ATM (ataxia telangiectasia mutated), and ATR (ataxia telangiectasia and Rad3-related protein), along with various structures of Rad51. However, structural information of the other major players involved, such as BRCA1 (breast cancer type 1 susceptibility protein) and BRCA2 (breast cancer type 2 susceptibility protein), has been limited to crystal structures of isolated domains and low-resolution electron microscopy reconstructions of the full-length proteins. Here we summarise the current structural understanding of homologous recombination, focusing on key proteins in recruitment and signalling events as well as the mediators for the Rad51 recombinase.
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Affiliation(s)
- Yueru Sun
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Thomas J McCorvie
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Luke A Yates
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK.
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12
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Garcin EB, Gon S, Sullivan MR, Brunette GJ, Cian AD, Concordet JP, Giovannangeli C, Dirks WG, Eberth S, Bernstein KA, Prakash R, Jasin M, Modesti M. Differential Requirements for the RAD51 Paralogs in Genome Repair and Maintenance in Human Cells. PLoS Genet 2019; 15:e1008355. [PMID: 31584931 PMCID: PMC6795472 DOI: 10.1371/journal.pgen.1008355] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 10/16/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022] Open
Abstract
Deficiency in several of the classical human RAD51 paralogs [RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3] is associated with cancer predisposition and Fanconi anemia. To investigate their functions, isogenic disruption mutants for each were generated in non-transformed MCF10A mammary epithelial cells and in transformed U2OS and HEK293 cells. In U2OS and HEK293 cells, viable ablated clones were readily isolated for each RAD51 paralog; in contrast, with the exception of RAD51B, RAD51 paralogs are cell-essential in MCF10A cells. Underlining their importance for genomic stability, mutant cell lines display variable growth defects, impaired sister chromatid recombination, reduced levels of stable RAD51 nuclear foci, and hyper-sensitivity to mitomycin C and olaparib, with the weakest phenotypes observed in RAD51B-deficient cells. Altogether these observations underscore the contributions of RAD51 paralogs in diverse DNA repair processes, and demonstrate essential differences in different cell types. Finally, this study will provide useful reagents to analyze patient-derived mutations and to investigate mechanisms of chemotherapeutic resistance deployed by cancers.
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Affiliation(s)
- Edwige B. Garcin
- Cancer Research Center of Marseille; CNRS; Inserm; Institut Paoli-Calmettes; Aix-Marseille Université, Marseille, France
| | - Stéphanie Gon
- Cancer Research Center of Marseille; CNRS; Inserm; Institut Paoli-Calmettes; Aix-Marseille Université, Marseille, France
| | - Meghan R. Sullivan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Gregory J. Brunette
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Anne De Cian
- Museum National d'Histoire Naturelle, Inserm U1154, CNRS UMR 7196, Sorbonne Universités, Paris, France
| | - Jean-Paul Concordet
- Museum National d'Histoire Naturelle, Inserm U1154, CNRS UMR 7196, Sorbonne Universités, Paris, France
| | - Carine Giovannangeli
- Museum National d'Histoire Naturelle, Inserm U1154, CNRS UMR 7196, Sorbonne Universités, Paris, France
| | - Wilhelm G. Dirks
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German, Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sonja Eberth
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German, Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Kara A. Bernstein
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Mauro Modesti
- Cancer Research Center of Marseille; CNRS; Inserm; Institut Paoli-Calmettes; Aix-Marseille Université, Marseille, France
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13
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Abstract
XRCC2 is one of five somatic RAD51 paralogs, all of which have Walker A and B ATPase motifs. Each of the paralogs, including XRCC2, has a function in DNA double-strand break repair by homologous recombination (HR). However, their individual roles are not as well understood as that of RAD51 itself. The XRCC2 protein forms a complex (BCDX2) with three other RAD51 paralogs, RAD51B, RAD51C and RAD51D. It is believed that the BCDX2 complex mediates HR downstream of BRCA2 but upstream of RAD51, as XRCC2 is involved in the assembly of RAD51 into DNA damage foci. XRCC2 can bind DNA and, along with RAD51D, can promote homologous pairing in vitro. Consistent with its role in HR, XRCC2-deficient cells have increased levels of spontaneous chromosome instability, and exhibit hypersensitivity to DNA interstrand crosslinking agents such as mitomycin C and cisplatin as well as ionizing radiation, alkylating agents and aldehydes. XRCC2 also functions in promoting DNA replication and chromosome segregation. Biallelic mutation of XRCC2 (FANCU) causes the FA-U subtype of FA, while heterozygosity for deleterious mutations in XRCC2 may be associated with an increased breast cancer risk. XRCC2 appears to function 'downstream' in the FA pathway, since it is not required for FANCD2 monoubiquitination, which is the central step in the FA pathway. Clinically, the only known FA-U patient in the world exhibits severe congenital abnormalities, but had not developed, by seven years of age, the bone marrow failure and cancer that are often seen in patients from other FA complementation groups.
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Affiliation(s)
- Paul R Andreassen
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; (PRA); Department of Pediatrics III, University Children's Hospital Essen, University Duisburg-Essen, Essen Germany; (HH)
| | - Helmut Hanenberg
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; (PRA); Department of Pediatrics III, University Children's Hospital Essen, University Duisburg-Essen, Essen Germany; (HH)
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14
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Reilly NM, Yard BD, Pittman DL. Homologous Recombination-Mediated DNA Repair and Implications for Clinical Treatment of Repair Defective Cancers. Methods Mol Biol 2019; 1999:3-29. [PMID: 31127567 DOI: 10.1007/978-1-4939-9500-4_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Double-strand DNA breaks (DSBs) are generated by ionizing radiation and as intermediates during the processing of DNA, such as repair of interstrand cross-links and collapsed replication forks. These potentially deleterious DSBs are repaired primarily by the homologous recombination (HR) and nonhomologous end joining (NHEJ) DNA repair pathways. HR utilizes a homologous template to accurately restore damaged DNA, whereas NHEJ utilizes microhomology to join breaks in close proximity. The pathway available for DSB repair is dependent upon the cell cycle stage; for example, HR primarily functions during the S/G2 stages while NHEJ can repair DSBs at any cell cycle stage. Posttranslational modifications (PTMs) promote activity of specific pathways and subpathways through enzyme activation and precisely timed protein recruitment and degradation. This chapter provides an overview of PTMs occurring during DSB repair. In addition, clinical phenotypes associated with HR-defective cancers, such as mutational signatures used to predict response to poly(ADP-ribose) polymerase inhibitors, are discussed. Understanding these processes will provide insight into mechanisms of genome maintenance and likely identify targets and new avenues for therapeutic interventions.
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Affiliation(s)
- Nicole M Reilly
- Fondazione Piemontese per la Ricerca sul Cancro ONLUS, Candiolo, Italy
| | - Brian D Yard
- Department of Translational Hematology and Oncology Research, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Douglas L Pittman
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA.
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15
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Ngoi NY, Tay D, Heong V, Thian YL, Ong PY, Ow SG, Jeyasekharan AD, Lim YW, Lim SE, Lee SC, Ng J, Low JJ, Ilancheran A, Koh SZ, Tan DS. Reversal of Bowel Obstruction With Platinum-Based Chemotherapy and Olaparib in Recurrent, Short Platinum-Free Interval, RAD51C Germline Mutation–Associated Ovarian Cancer. JCO Precis Oncol 2018; 2:1-8. [DOI: 10.1200/po.18.00008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Natalie Y.L. Ngoi
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Darwin Tay
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Valerie Heong
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Yee Liang Thian
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Pei Yi Ong
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Samuel G.W. Ow
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Anand D. Jeyasekharan
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Yi Wan Lim
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Siew Eng Lim
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Soo Chin Lee
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Joseph Ng
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Jeffrey J.H. Low
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Arunachalam Ilancheran
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - Sharon Z.L. Koh
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
| | - David S.P. Tan
- Natalie Y.L. Ngoi, Valerie Heong, Pei Yi Ong, Samuel G.W. Ow, Anand D. Jeyasekharan, Yi Wan Lim, Siew Eng Lim, Soo Chin Lee, and David S.P. Tan, National University Cancer Institute; Darwin Tay, Valerie Heong, Anand D. Jeyasekharan, Soo Chin Lee, and David S.P. Tan, National University of Singapore; Yee Liang Thian, Joseph Ng, Jeffrey J.H. Low, Arunachalam Ilancheran, and Sharon Z.L. Koh, National University Hospital, Singapore, Republic of Singapore
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16
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Xu Z, Zhang J, Xu M, Ji W, Yu M, Tao Y, Gong Z, Gu M, Yu H. Rice RAD51 paralogs play essential roles in somatic homologous recombination for DNA repair. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:282-295. [PMID: 29729110 DOI: 10.1111/tpj.13949] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Synthesis-dependent strand annealing (SDSA) and single-strand annealing (SSA) are the two main homologous recombination (HR) pathways in double-strand break (DSB) repair. The involvement of rice RAD51 paralogs in HR is well known in meiosis, although the molecular mechanism in somatic HR remains obscure. Loss-of-function mutants of rad51 paralogs show increased sensitivity to the DSB-inducer bleomycin, which results in greatly compromised somatic recombination efficiencies (xrcc3 in SDSA, rad51b and xrcc2 in SSA, rad51c and rad51d in both). Using immunostaining, we found that mutations in RAD51 paralogs (XRCC3, RAD51C, or RAD51D) lead to tremendous impairment in RAD51 focus formation at DSBs. Intriguingly, the RAD51C mutation has a strong effect on the protein loading of its partners (XRCC3 and RAD51B) at DSBs, which is similar to the phenomenon observed in the case of blocking PI3K-like kinases in wild-type plant. We conclude that the rice CDX3 complex acts in SDSA recombination while the BCDX2 complex acts in SSA recombination in somatic DSB repair. Importantly, RAD51C serves as a fulcrum for the local recruitment of its partners (XRCC3 for SDSA and RAD51B for SSA) and is positively modulated by PI3K-like kinases to facilitate both the SDSA and SSA pathways in RAD51 paralog-dependent somatic HR.
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Affiliation(s)
- Zhan Xu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Jianxiang Zhang
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Meng Xu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Wen Ji
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Meimei Yu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Yajun Tao
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zhiyun Gong
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Minghong Gu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Hengxiu Yu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
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17
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Zheng M, Lu J, Zhao D. Toxicity and Transcriptome Sequencing (RNA-seq) Analyses of Adult Zebrafish in Response to Exposure Carboxymethyl Cellulose Stabilized Iron Sulfide Nanoparticles. Sci Rep 2018; 8:8083. [PMID: 29795396 PMCID: PMC5967324 DOI: 10.1038/s41598-018-26499-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 05/14/2018] [Indexed: 01/20/2023] Open
Abstract
Increasing utilization of stabilized iron sulfides (FeS) nanoparticles implies an elevated release of the materials into the environment. To understand potential impacts and underlying mechanisms of nanoparticle-induced stress, we used the transcriptome sequencing (RNA-seq) technique to characterize the transcriptomes from adult zebrafish exposed to 10 mg/L carboxymethyl cellulose (CMC) stabilized FeS nanoparticles for 96 h, demonstrating striking differences in the gene expression profiles in liver. The exposure caused significant expression alterations in genes related to immune and inflammatory responses, detoxification, oxidative stress and DNA damage/repair. The complement and coagulation cascades Kyoto encyclopedia of genes and genomes (KEGG) pathway was found significantly up-regulated under nanoparticle exposure. The quantitative real-time polymerase chain reaction using twelve genes confirmed the RNA-seq results. We identified several candidate genes commonly regulated in liver, which may serve as gene indicators when exposed to the nanoparticles. Hepatic inflammation was further confirmed by histological observation of pyknotic nuclei, and vacuole formation upon exposure. Tissue accumulation tests showed a 2.2 times higher iron concentration in the fish tissue upon exposure. This study provides preliminary mechanistic insights into potential toxic effects of organic matter stabilized FeS nanoparticles, which will improve our understanding of the genotoxicity caused by stabilized nanoparticles.
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Affiliation(s)
- Min Zheng
- Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL, 36849, USA.,School of Marine Sciences, Sun Yat-sen University, Guangdong, 510275, China
| | - Jianguo Lu
- School of Marine Sciences, Sun Yat-sen University, Guangdong, 510275, China
| | - Dongye Zhao
- Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL, 36849, USA. .,Beijing University of Civil Engineering and Architecture, Beijing, 100044, PR China.
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18
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Hutinet G, Besle A, Son O, McGovern S, Guerois R, Petit MA, Ochsenbein F, Lecointe F. Sak4 of Phage HK620 Is a RecA Remote Homolog With Single-Strand Annealing Activity Stimulated by Its Cognate SSB Protein. Front Microbiol 2018; 9:743. [PMID: 29740405 PMCID: PMC5928155 DOI: 10.3389/fmicb.2018.00743] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/29/2018] [Indexed: 12/19/2022] Open
Abstract
Bacteriophages are remarkable for the wide diversity of proteins they encode to perform DNA replication and homologous recombination. Looking back at these ancestral forms of life may help understanding how similar proteins work in more sophisticated organisms. For instance, the Sak4 family is composed of proteins similar to the archaeal RadB protein, a Rad51 paralog. We have previously shown that Sak4 allowed single-strand annealing in vivo, but only weakly compared to the phage λ Redβ protein, highlighting putatively that Sak4 requires partners to be efficient. Here, we report that the purified Sak4 of phage HK620 infecting Escherichia coli is a poorly efficient annealase on its own. A distant homolog of SSB, which gene is usually next to the sak4 gene in various species of phages, highly stimulates its recombineering activity in vivo. In vitro, Sak4 binds single-stranded DNA and performs single-strand annealing in an ATP-dependent way. Remarkably, the single-strand annealing activity of Sak4 is stimulated by its cognate SSB. The last six C-terminal amino acids of this SSB are essential for the binding of Sak4 to SSB-covered single-stranded DNA, as well as for the stimulation of its annealase activity. Finally, expression of sak4 and ssb from HK620 can promote low-level of recombination in vivo, though Sak4 and its SSB are unable to promote strand exchange in vitro. Regarding its homology with RecA, Sak4 could represent a link between two previously distinct types of recombinases, i.e., annealases that help strand exchange proteins and strand exchange proteins themselves.
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Affiliation(s)
- Geoffrey Hutinet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Arthur Besle
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Olivier Son
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Stephen McGovern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Raphaël Guerois
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marie-Agnès Petit
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Françoise Ochsenbein
- Institute for Integrative Biology of the Cell (I2BC), IBITECS, CEA, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - François Lecointe
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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19
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Tvedte ES, Forbes AA, Logsdon JM. Retention of Core Meiotic Genes Across Diverse Hymenoptera. J Hered 2018; 108:791-806. [PMID: 28992199 DOI: 10.1093/jhered/esx062] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 07/13/2017] [Indexed: 12/20/2022] Open
Abstract
The cellular mechanisms of meiosis are critical for proper gamete formation in sexual organisms. Functional studies in model organisms have identified genes essential for meiosis, yet the extent to which this core meiotic machinery is conserved across non-model systems is not fully understood. Moreover, it is unclear whether deviation from canonical modes of sexual reproduction is accompanied by modifications in the genetic components involved in meiosis. We used a robust approach to identify and catalogue meiosis genes in Hymenoptera, an insect order typically characterized by haplodiploid reproduction. Using newly available genome data, we searched for 43 genes involved in meiosis in 18 diverse hymenopterans. Seven of eight genes with roles specific to meiosis were found across a majority of surveyed species, suggesting the preservation of core meiotic machinery in haplodiploid hymenopterans. Phylogenomic analyses of the inventory of meiosis genes and the identification of shared gene duplications and losses provided support for the grouping of species within Proctotrupomorpha, Ichneumonomorpha, and Aculeata clades, along with a paraphyletic Symphyta. The conservation of meiosis genes across Hymenoptera provides a framework for studying transitions between reproductive modes in this insect group.
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Affiliation(s)
- Eric S Tvedte
- Department of Biology, University of Iowa, Iowa City, IA 52242
| | - Andrew A Forbes
- Department of Biology, University of Iowa, Iowa City, IA 52242
| | - John M Logsdon
- Department of Biology, University of Iowa, Iowa City, IA 52242
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20
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Knies K, Inano S, Ramírez MJ, Ishiai M, Surrallés J, Takata M, Schindler D. Biallelic mutations in the ubiquitin ligase RFWD3 cause Fanconi anemia. J Clin Invest 2017; 127:3013-3027. [PMID: 28691929 DOI: 10.1172/jci92069] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 05/16/2017] [Indexed: 12/28/2022] Open
Abstract
The WD40-containing E3 ubiquitin ligase RFWD3 has been recently linked to the repair of DNA damage by homologous recombination (HR). Here we have shown that an RFWD3 mutation within the WD40 domain is connected to the genetic disease Fanconi anemia (FA). An individual presented with congenital abnormalities characteristic of FA. Cells from the patient carrying the compound heterozygous mutations c.205_206dupCC and c.1916T>A in RFWD3 showed increased sensitivity to DNA interstrand cross-linking agents in terms of increased chromosomal breakage, reduced survival, and cell cycle arrest in G2 phase. The cellular phenotype was mirrored in genetically engineered human and avian cells by inactivation of RFWD3 or introduction of the patient-derived missense mutation, and the phenotype was rescued by expression of wild-type RFWD3 protein. HR was disrupted in RFWD3-mutant cells as a result of impaired relocation of mutant RFWD3 to chromatin and defective physical interaction with replication protein A. Rfwd3 knockout mice appear to have increased embryonic lethality, are subfertile, show ovarian and testicular atrophy, and have a reduced lifespan resembling that of other FA mouse models. Although RFWD3 mutations have thus far been detected in a single child with FA, we propose RFWD3 as an FA gene, FANCW, supported by cellular paradigm systems and an animal model.
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Affiliation(s)
- Kerstin Knies
- Department of Human Genetics, Biozentrum, University of Wurzburg, Wurzburg, Germany
| | - Shojiro Inano
- Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center, Kyoto University, Kyoto, Japan.,Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - María J Ramírez
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Masamichi Ishiai
- Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - Jordi Surrallés
- Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain.,Genetics Department, Hospital de Sant Pau, Barcelona, Spain
| | - Minoru Takata
- Laboratory of DNA Damage Signaling, Department of Late Effects Studies, Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - Detlev Schindler
- Department of Human Genetics, Biozentrum, University of Wurzburg, Wurzburg, Germany
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21
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Yong KJ, Milenic DE, Baidoo KE, Brechbiel MW. Cell Killing Mechanisms and Impact on Gene Expression by Gemcitabine and 212Pb-Trastuzumab Treatment in a Disseminated i.p. Tumor Model. PLoS One 2016; 11:e0159904. [PMID: 27467592 PMCID: PMC4965152 DOI: 10.1371/journal.pone.0159904] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 06/22/2016] [Indexed: 11/18/2022] Open
Abstract
In pre-clinical studies, combination therapy with gemcitabine and targeted radioimmunotherapy (RIT) using 212Pb-trastuzumab showed tremendous therapeutic potential in the LS-174T tumor xenograft model of disseminated intraperitoneal disease. To better understand the underlying molecular basis for the observed cell killing efficacy, gene expression profiling was performed after a 24 h exposure to 212Pb-trastuzumab upon gemcitabine (Gem) pre-treatment in this model. DNA damage response genes in tumors were quantified using a real time quantitative PCR array (qRT-PCR array) covering 84 genes. The combination of Gem with α-radiation resulted in the differential expression of apoptotic genes (BRCA1, CIDEA, GADD45α, GADD45γ, IP6K3, PCBP4, RAD21, and p73), cell cycle regulatory genes (BRCA1, CHK1, CHK2, FANCG, GADD45α, GTSE1, PCBP4, MAP2K6, NBN, PCBP4, and SESN1), and damaged DNA binding and repair genes (BRCA1, BTG2, DMC1, ERCC1, EXO1, FANCG, FEN1, MSH2, MSH3, NBN, NTHL1, OGG1, PRKDC, RAD18, RAD21, RAD51B, SEMA4G, p73, UNG, XPC, and XRCC2). Of these genes, the expression of CHK1, GTSE1, EXO1, FANCG, RAD18, UNG and XRCC2 were specific to Gem/212Pb-trastuzumab administration. In addition, the present study demonstrates that increased stressful growth arrest conditions induced by Gem/212Pb-trastuzumab could suppress cell proliferation possibly by up-regulating genes involved in apoptosis such as p73, by down-regulating genes involved in cell cycle check point such as CHK1, and in damaged DNA repair such as RAD51 paralogs. These events may be mediated by genes such as BRCA1/MSH2, a member of BARC (BRCA-associated genome surveillance complex). The data suggest that up-regulation of genes involved in apoptosis, perturbation of checkpoint genes, and a failure to correctly perform HR-mediated DSB repair and mismatch-mediated SSB repair may correlate with the previously observed inability to maintain the G2/M arrest, leading to cell death.
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Affiliation(s)
- Kwon Joong Yong
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD, United States of America
| | - Diane E. Milenic
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD, United States of America
| | - Kwamena E. Baidoo
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD, United States of America
| | - Martin W. Brechbiel
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda MD, United States of America
- * E-mail:
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22
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Kalvala A, Gao L, Aguila B, Dotts K, Rahman M, Nana-Sinkam SP, Zhou X, Wang QE, Amann J, Otterson GA, Villalona-Calero MA, Duan W. Rad51C-ATXN7 fusion gene expression in colorectal tumors. Mol Cancer 2016; 15:47. [PMID: 27296891 PMCID: PMC4906819 DOI: 10.1186/s12943-016-0527-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 05/20/2016] [Indexed: 11/10/2022] Open
Abstract
Background Fusion proteins have unique oncogenic properties and their identification can be useful either as diagnostic or therapeutic targets. Next generation sequencing data have previously shown a fusion gene formed between Rad51C and ATXN7 genes in the MCF7 breast cancer cell line. However, the existence of this fusion gene in colorectal patient tumor tissues is largely still unknown. Methods We evaluated for the presence of Rad51C-ATXN7 fusion gene in colorectal tumors and cells by RT-PCR, PCR, Topo TA cloning, Real time PCR, immunoprecipitation and immunoblotting techniques. Results We identified two forms of fusion mRNAs between Rad51C and ATXN7 in the colorectal tumors, including a Variant 1 (fusion transcript between Rad51C exons 1–7 and ATXN7 exons 6–13), and a Variant 2 (between Rad51C exons 1–6 and ATXN7 exons 6–13). In silico analysis showed that the Variant 1 produces a truncated protein, whereas the Variant 2 was predicted to produce a fusion protein with molecular weight of 110 KDa. Immunoprecipitation and Western blot analysis further showed a 110 KDa protein in colorectal tumors. 5-Azacytidine treatment of LS-174 T cells caused a 3.51-fold increase in expression of the fusion gene (Variant 2) as compared to no treatment controls evaluated by real time PCR. Conclusion In conclusion we found a fusion gene between DNA repair gene Rad51C and neuro-cerebral ataxia Ataxin-7 gene in colorectal tumors. The in-frame fusion transcript of Variant 2 results in a fusion protein with molecular weight of 110 KDa. In addition, we found that expression of fusion gene is associated with functional impairment of Fanconi Anemia (FA) DNA repair pathway in colorectal tumors. The expression of Rad51C-ATXN7 in tumors warrants further investigation, as it suggests the potential of the fusion gene in treatment and predictive value in colorectal cancers. Electronic supplementary material The online version of this article (doi:10.1186/s12943-016-0527-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Arjun Kalvala
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Li Gao
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Brittany Aguila
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Kathleen Dotts
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Mohammad Rahman
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Serge P Nana-Sinkam
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA.,Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Xiaoping Zhou
- Department of Pathology, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Qi-En Wang
- Department of Radiology, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Joseph Amann
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA.,Division of Medical Oncology Department of Internal Medicine, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Gregory A Otterson
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA.,Division of Medical Oncology Department of Internal Medicine, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA
| | - Miguel A Villalona-Calero
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA. .,Division of Medical Oncology Department of Internal Medicine, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA. .,Department of Pharmacology, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA.
| | - Wenrui Duan
- Comprehensive Cancer Center, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA. .,Division of Medical Oncology Department of Internal Medicine, the Ohio State University College of Medicine and Public Health, Columbus, Ohio, 43210, USA.
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23
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Godin SK, Sullivan MR, Bernstein KA. Novel insights into RAD51 activity and regulation during homologous recombination and DNA replication. Biochem Cell Biol 2016; 94:407-418. [PMID: 27224545 DOI: 10.1139/bcb-2016-0012] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this review we focus on new insights that challenge our understanding of homologous recombination (HR) and Rad51 regulation. Recent advances using high-resolution microscopy and single molecule techniques have broadened our knowledge of Rad51 filament formation and strand invasion at double-strand break (DSB) sites and at replication forks, which are one of most physiologically relevant forms of HR from yeast to humans. Rad51 filament formation and strand invasion is regulated by many mediator proteins such as the Rad51 paralogues and the Shu complex, consisting of a Shu2/SWS1 family member and additional Rad51 paralogues. Importantly, a novel RAD51 paralogue was discovered in Caenorhabditis elegans, and its in vitro characterization has demonstrated a new function for the worm RAD51 paralogues during HR. Conservation of the human RAD51 paralogues function during HR and repair of replicative damage demonstrate how the RAD51 mediators play a critical role in human health and genomic integrity. Together, these new findings provide a framework for understanding RAD51 and its mediators in DNA repair during multiple cellular contexts.
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Affiliation(s)
- Stephen K Godin
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics.,University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
| | - Meghan R Sullivan
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics.,University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
| | - Kara A Bernstein
- University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, and the Department of Microbiology and Molecular Genetics
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24
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Richter KS, Serra H, White CI, Jeske H. The recombination mediator RAD51D promotes geminiviral infection. Virology 2016; 493:113-27. [PMID: 27018825 DOI: 10.1016/j.virol.2016.03.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/15/2016] [Accepted: 03/18/2016] [Indexed: 11/28/2022]
Abstract
To study a possible role for homologous recombination in geminivirus replication, we challenged Arabidopsis recombination gene knockouts by Euphorbia yellow mosaic virus infection. Our results show that the RAD51 paralog RAD51D, rather than RAD51 itself, promotes viral replication at early stages of infection. Blot hybridization analyses of replicative intermediates using one- and two-dimensional gels and deep sequencing point to an unexpected facet of recombination-dependent replication, the repair by single-strand annealing (SSA) during complementary strand replication. A significant decrease of both intramolecular, yielding defective DNAs and intermolecular recombinant molecules between the two geminiviral DNA components (A, B) were observed in the absence of RAD51D. By contrast, DNA A and B reacted differentially with the generation of inversions. A model to implicate single-strand annealing recombination in geminiviral recombination-dependent replication is proposed.
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Affiliation(s)
- Kathrin S Richter
- Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany
| | - Heϊdi Serra
- Génétique, Reproduction et Développement, UMR CNRS 6293-Clermont Université- INSERM U1103 Aubière, France
| | - Charles I White
- Génétique, Reproduction et Développement, UMR CNRS 6293-Clermont Université- INSERM U1103 Aubière, France
| | - Holger Jeske
- Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
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25
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Kalvala A, Gao L, Aguila B, Reese T, Otterson GA, Villalona-Calero MA, Duan W. Overexpression of Rad51C splice variants in colorectal tumors. Oncotarget 2016; 6:8777-87. [PMID: 25669972 PMCID: PMC4496183 DOI: 10.18632/oncotarget.3209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 12/24/2014] [Indexed: 01/04/2023] Open
Abstract
Functional alterations in Rad51C are the cause of the Fanconi anemia complementation group O (FANCO) gene disorder. We have identified novel splice variants of Rad51C mRNA in colorectal tumors and cells. The alternatively spliced transcript variants are formed either without exon-7 (variant 1), without exon 6 and 7 (variant 2) or without exon 7 and 8 (variant 3). Real time PCR analysis of nine pair-matched colorectal tumors and non-tumors showed that variant 1 was overexpressed in tumors compared to matched non-tumors. Among 38 colorectal tumor RNA samples analyzed, 18 contained variant 1, 12 contained variant 2, 14 contained variant 3, and eight expressed full length Rad51C exclusively. Bisulfite DNA sequencing showed promoter methylation of Rad51C in tumor cells. 5-azacytidine treatment of LS-174T cells caused a 14 fold increase in variant 1, a 4.8 fold increase for variant 3 and 3.4 fold for variant 2 compared to 2.5 fold increase in WT. Expression of Rad51C variants is associated with FANCD2 foci positive colorectal tumors and is associated with microsatellite stability in those tumors. Further investigation is needed to elucidate differential function of the Rad51C variants to evaluate potential effects in drug resistance and DNA repair.
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Affiliation(s)
- Arjun Kalvala
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Li Gao
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Brittany Aguila
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Tyler Reese
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Gregory A Otterson
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A.,Division of Medical Oncology Department of Internal Medicine, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Miguel A Villalona-Calero
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A.,Division of Medical Oncology Department of Internal Medicine, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A.,Department of Pharmacology at The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
| | - Wenrui Duan
- Comprehensive Cancer Center, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A.,Division of Medical Oncology Department of Internal Medicine, The Ohio State University College of Medicine and Public Health, Columbus, Ohio, U.S.A
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26
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Prakash R, Zhang Y, Feng W, Jasin M. Homologous recombination and human health: the roles of BRCA1, BRCA2, and associated proteins. Cold Spring Harb Perspect Biol 2015; 7:a016600. [PMID: 25833843 DOI: 10.1101/cshperspect.a016600] [Citation(s) in RCA: 576] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks in mammalian cells, the defining step of which is homologous strand exchange directed by the RAD51 protein. The physiological importance of HR is underscored by the observation of genomic instability in HR-deficient cells and, importantly, the association of cancer predisposition and developmental defects with mutations in HR genes. The tumor suppressors BRCA1 and BRCA2, key players at different stages of HR, are frequently mutated in familial breast and ovarian cancers. Other HR proteins, including PALB2 and RAD51 paralogs, have also been identified as tumor suppressors. This review summarizes recent findings on BRCA1, BRCA2, and associated proteins involved in human disease with an emphasis on their molecular roles and interactions.
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Affiliation(s)
- Rohit Prakash
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Yu Zhang
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Weiran Feng
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065 Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York 10065
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27
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Morrical SW. DNA-pairing and annealing processes in homologous recombination and homology-directed repair. Cold Spring Harb Perspect Biol 2015; 7:a016444. [PMID: 25646379 DOI: 10.1101/cshperspect.a016444] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The formation of heteroduplex DNA is a central step in the exchange of DNA sequences via homologous recombination, and in the accurate repair of broken chromosomes via homology-directed repair pathways. In cells, heteroduplex DNA largely arises through the activities of recombination proteins that promote DNA-pairing and annealing reactions. Classes of proteins involved in pairing and annealing include RecA-family DNA-pairing proteins, single-stranded DNA (ssDNA)-binding proteins, recombination mediator proteins, annealing proteins, and nucleases. This review explores the properties of these pairing and annealing proteins, and highlights their roles in complex recombination processes including the double Holliday junction (DhJ) formation, synthesis-dependent strand annealing, and single-strand annealing pathways--DNA transactions that are critical both for genome stability in individual organisms and for the evolution of species.
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Affiliation(s)
- Scott W Morrical
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont 05405
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28
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Tang D, Miao C, Li Y, Wang H, Liu X, Yu H, Cheng Z. OsRAD51C is essential for double-strand break repair in rice meiosis. FRONTIERS IN PLANT SCIENCE 2014; 5:167. [PMID: 24847337 PMCID: PMC4019848 DOI: 10.3389/fpls.2014.00167] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/08/2014] [Indexed: 05/18/2023]
Abstract
RAD51C is one of the RAD51 paralogs that plays an important role in DNA double-strand break repair by homologous recombination. Here, we identified and characterized OsRAD51C, the rice homolog of human RAD51C. The Osrad51c mutant plant is normal in vegetative growth but exhibits complete male and female sterility. Cytological investigation revealed that homologous pairing and synapsis were severely disrupted. Massive chromosome fragmentation occurred during metaphase I in Osrad51c meiocytes, and was fully suppressed by the CRC1 mutation. Immunofluorescence analysis showed that OsRAD51C localized onto the chromosomes from leptotene to early pachytene during prophase I, and that normal loading of OsRAD51C was dependent on OsREC8, PAIR2, and PAIR3. Additionally, ZEP1 did not localize properly in Osrad51c, indicating that OsRAD51C is required for synaptonemal complex assembly. Our study also provided evidence in support of a functional divergence in RAD51C among organisms.
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Affiliation(s)
- Ding Tang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
| | - Chunbo Miao
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
| | - Yafei Li
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
| | - Hongjun Wang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
| | - Xiaofei Liu
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
| | - Hengxiu Yu
- Key Laboratory of Plant Functional Genomics of Ministry of Education, Yangzhou UniversityYangzhou, China
| | - Zhukuan Cheng
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China
- *Correspondence: Zhukuan Cheng, State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang Distict, Beijing 100101, China e-mail:
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29
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Roles of XRCC2, RAD51B and RAD51D in RAD51-independent SSA recombination. PLoS Genet 2013; 9:e1003971. [PMID: 24278037 PMCID: PMC3836719 DOI: 10.1371/journal.pgen.1003971] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/07/2013] [Indexed: 11/19/2022] Open
Abstract
The repair of DNA double-strand breaks by recombination is key to the maintenance of genome integrity in all living organisms. Recombination can however generate mutations and chromosomal rearrangements, making the regulation and the choice of specific pathways of great importance. In addition to end-joining through non-homologous recombination pathways, DNA breaks are repaired by two homology-dependent pathways that can be distinguished by their dependence or not on strand invasion catalysed by the RAD51 recombinase. Working with the plant Arabidopsis thaliana, we present here an unexpected role in recombination for the Arabidopsis RAD51 paralogues XRCC2, RAD51B and RAD51D in the RAD51-independent single-strand annealing pathway. The roles of these proteins are seen in spontaneous and in DSB-induced recombination at a tandem direct repeat recombination tester locus, both of which are unaffected by the absence of RAD51. Individual roles of these proteins are suggested by the strikingly different severities of the phenotypes of the individual mutants, with the xrcc2 mutant being the most affected, and this is confirmed by epistasis analyses using multiple knockouts. Notwithstanding their clearly established importance for RAD51-dependent homologous recombination, XRCC2, RAD51B and RAD51D thus also participate in Single-Strand Annealing recombination.
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30
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Da Ines O, Degroote F, Amiard S, Goubely C, Gallego ME, White CI. Effects of XRCC2 and RAD51B mutations on somatic and meiotic recombination in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:959-70. [PMID: 23521529 DOI: 10.1111/tpj.12182] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/11/2013] [Accepted: 03/15/2013] [Indexed: 05/12/2023]
Abstract
Homologous recombination is key to the maintenance of genome integrity and the creation of genetic diversity. At the mechanistic level, recombination involves the invasion of a homologous DNA template by broken DNA ends, repair of the break and exchange of genetic information between the two DNA molecules. Invasion of the template in eukaryotic cells is catalysed by the RAD51 and DMC1 recombinases, assisted by a number of accessory proteins, including the RAD51 paralogues. Eukaryotic genomes encode a variable number of RAD51 paralogues, ranging from two in yeast to five in animals and plants. The RAD51 paralogues form at least two distinct protein complexes, believed to play roles in the assembly and stabilization of the RAD51-DNA nucleofilament. Somatic recombination assays and immunocytology confirm that the three 'non-meiotic' paralogues of Arabidopsis, RAD51B, RAD51D and XRCC2, are involved in somatic homologous recombination, and that they are not required for the formation of radioinduced RAD51 foci. Given the presence of all five proteins in meiotic cells, the apparent absence of a meiotic role for RAD51B, RAD51D and XRCC2 is surprising, and perhaps simply the result of a more subtle meiotic phenotype in the mutants. Analysis of meiotic recombination confirms this, showing that the absence of XRCC2, and to a lesser extent RAD51B, but not RAD51D, increases rates of meiotic crossing over. The roles of RAD51B and XRCC2 in recombination are thus not limited to mitotic cells.
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Affiliation(s)
- Olivier Da Ines
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, 63171, Aubière, France
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31
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Godin S, Wier A, Kabbinavar F, Bratton-Palmer DS, Ghodke H, Van Houten B, VanDemark AP, Bernstein KA. The Shu complex interacts with Rad51 through the Rad51 paralogues Rad55-Rad57 to mediate error-free recombination. Nucleic Acids Res 2013; 41:4525-34. [PMID: 23460207 PMCID: PMC3632125 DOI: 10.1093/nar/gkt138] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Saccharomyces cerevisiae Shu complex, consisting of Shu1, Shu2, Csm2 and Psy3, promotes error-free homologous recombination (HR) by an unknown mechanism. Recent structural analysis of two Shu proteins, Csm2 and Psy3, has revealed that these proteins are Rad51 paralogues and mediate DNA binding of this complex. We show in vitro that the Csm2–Psy3 heterodimer preferentially binds synthetic forked DNA or 3′-DNA overhang substrates resembling structures used during HR in vivo. We find that Csm2 interacts with Rad51 and the Rad51 paralogues, the Rad55–Rad57 heterodimer and that the Shu complex functions in the same epistasis group as Rad55–Rad57. Importantly, Csm2’s interaction with Rad51 is dependent on Rad55, whereas Csm2’s interaction with Rad55 occurs independently of Rad51. Consistent with the Shu complex containing Rad51 paralogues, the methyl methanesulphonate sensitivity of Csm2 is exacerbated at colder temperatures. Furthermore, Csm2 and Psy3 are needed for efficient recruitment of Rad55 to DNA repair foci after DNA damage. Finally, we observe that the Shu complex preferentially promotes Rad51-dependent homologous recombination over Rad51-independent repair. Our data suggest a model in which Csm2–Psy3 recruit the Shu complex to HR substrates, where it interacts with Rad51 through Rad55–Rad57 to stimulate Rad51 filament assembly and stability, promoting error-free repair.
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Affiliation(s)
- Stephen Godin
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA
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32
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Unwinding and rewinding: double faces of helicase? J Nucleic Acids 2012; 2012:140601. [PMID: 22888405 PMCID: PMC3409536 DOI: 10.1155/2012/140601] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 05/28/2012] [Indexed: 12/29/2022] Open
Abstract
Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity—in other words, they can anneal two complementary single-stranded nucleic acids. All five members of the human RecQ helicase family, helicase PIF1, mitochondrial helicase TWINKLE, and helicase/nuclease Dna2 have been shown to possess strand-annealing activity. Moreover, two recently identified helicases—HARP and AH2 have only ATP-dependent rewinding activity. These findings not only enhance our understanding of helicase enzymes but also establish the presence of a new type of protein: annealing helicases. This paper discusses what is known about these helicases, focusing on their biochemical activity to zip and unzip double-stranded DNA and/or RNA, their possible regulation mechanisms, and biological functions.
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33
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She Z, Gao ZQ, Liu Y, Wang WJ, Liu GF, Shtykova EV, Xu JH, Dong YH. Structural and SAXS analysis of the budding yeast SHU-complex proteins. FEBS Lett 2012; 586:2306-12. [PMID: 22749910 DOI: 10.1016/j.febslet.2012.06.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/08/2012] [Accepted: 06/14/2012] [Indexed: 11/25/2022]
Abstract
In Saccharomyces cerevisiae, four proteins, Shu1, Shu2, Psy3 and Csm2, form a stable SHU-complex both in vivo and in vitro. These proteins are involved in the early stages of the homologous recombination DNA damage repair process. In this paper, the crystal structure of the Psy3-Csm2 sub-complex is presented at 1.8Å resolution and successfully fitted into our small angle X-ray scattering (SAXS) data of the SHU-complex. Taken together with our electrophoretic mobility shift assay (EMSA) results, a model is proposed for the SHU-protein complex coupled with DNA.
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Affiliation(s)
- Zhun She
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
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34
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Krejci L, Altmannova V, Spirek M, Zhao X. Homologous recombination and its regulation. Nucleic Acids Res 2012; 40:5795-818. [PMID: 22467216 PMCID: PMC3401455 DOI: 10.1093/nar/gks270] [Citation(s) in RCA: 456] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Homologous recombination (HR) is critical both for repairing DNA lesions in mitosis and for chromosomal pairing and exchange during meiosis. However, some forms of HR can also lead to undesirable DNA rearrangements. Multiple regulatory mechanisms have evolved to ensure that HR takes place at the right time, place and manner. Several of these impinge on the control of Rad51 nucleofilaments that play a central role in HR. Some factors promote the formation of these structures while others lead to their disassembly or the use of alternative repair pathways. In this article, we review these mechanisms in both mitotic and meiotic environments and in different eukaryotic taxa, with an emphasis on yeast and mammal systems. Since mutations in several proteins that regulate Rad51 nucleofilaments are associated with cancer and cancer-prone syndromes, we discuss how understanding their functions can lead to the development of better tools for cancer diagnosis and therapy.
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Affiliation(s)
- Lumir Krejci
- Department of Biology, Masaryk University, Brno, Czech Republic.
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35
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Suwaki N, Klare K, Tarsounas M. RAD51 paralogs: roles in DNA damage signalling, recombinational repair and tumorigenesis. Semin Cell Dev Biol 2011; 22:898-905. [PMID: 21821141 DOI: 10.1016/j.semcdb.2011.07.019] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 07/19/2011] [Accepted: 07/21/2011] [Indexed: 11/18/2022]
Abstract
Chromosomal double-strand breaks (DSBs) have the potential to permanently arrest cell cycle progression and endanger cell survival. They must therefore be efficiently repaired to preserve genome integrity and functionality. Homologous recombination (HR) provides an important error-free mechanism for DSB repair in mammalian cells. In addition to RAD51, the central recombinase activity in mammalian cells, a family of proteins known as the RAD51 paralogs and consisting of five proteins (RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3), play an essential role in the DNA repair reactions through HR. The RAD51 paralogs act to transduce the DNA damage signal to effector kinases and to promote break repair. However, their precise cellular functions are not fully elucidated. Here we discuss recent advances in our understanding of how these factors mediate checkpoint responses and act in the HR repair process. In addition, we highlight potential functional similarities with the BRCA2 tumour suppressor, through the recently reported links between RAD51 paralog deficiencies and tumorigenesis triggered by genome instability.
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Affiliation(s)
- Natsuko Suwaki
- The Cancer Research UK/Medical Research Council Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, UK
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36
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Deakyne JS, Mazin AV. Fanconi anemia: at the crossroads of DNA repair. BIOCHEMISTRY (MOSCOW) 2011; 76:36-48. [PMID: 21568838 DOI: 10.1134/s0006297911010068] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fanconi anemia (FA) is an autosomal disorder that causes genome instability. FA patients suffer developmental abnormalities, early-onset bone marrow failure, and a predisposition to cancer. The disease is manifested by defects in DNA repair, hypersensitivity to DNA crosslinking agents, and a high degree of chromosomal aberrations. The FA pathway comprises 13 disease-causing genes involved in maintaining genomic stability. The fast pace of study of the novel DNA damage network has led to the constant discovery of new FA-like genes involved in the pathway that when mutated lead to similar disorders. A majority of the FA proteins act as signal transducers and scaffolding proteins to employ other pathways to repair DNA. This review discusses what is known about the FA proteins and other recently linked FA-like proteins. The goal is to clarify how the proteins work together to carry out interstrand crosslink repair and homologous recombination-mediated repair of damaged DNA.
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Affiliation(s)
- J S Deakyne
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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37
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Liu J, Ehmsen KT, Heyer WD, Morrical SW. Presynaptic filament dynamics in homologous recombination and DNA repair. Crit Rev Biochem Mol Biol 2011; 46:240-70. [PMID: 21599536 DOI: 10.3109/10409238.2011.576007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Homologous recombination (HR) is an essential genome stability mechanism used for high-fidelity repair of DNA double-strand breaks and for the recovery of stalled or collapsed DNA replication forks. The crucial homology search and DNA strand exchange steps of HR are catalyzed by presynaptic filaments-helical filaments of a recombinase enzyme bound to single-stranded DNA (ssDNA). Presynaptic filaments are fundamentally dynamic structures, the assembly, catalytic turnover, and disassembly of which must be closely coordinated with other elements of the DNA recombination, repair, and replication machinery in order for genome maintenance functions to be effective. Here, we reviewed the major dynamic elements controlling the assembly, activity, and disassembly of presynaptic filaments; some intrinsic such as recombinase ATP-binding and hydrolytic activities, others extrinsic such as ssDNA-binding proteins, mediator proteins, and DNA motor proteins. We examined dynamic behavior on multiple levels, including atomic- and filament-level structural changes associated with ATP binding and hydrolysis as evidenced in crystal structures, as well as subunit binding and dissociation events driven by intrinsic and extrinsic factors. We examined the biochemical properties of recombination proteins from four model systems (T4 phage, Escherichia coli, Saccharomyces cerevisiae, and Homo sapiens), demonstrating how their properties are tailored for the context-specific requirements in these diverse species. We proposed that the presynaptic filament has evolved to rely on multiple external factors for increased multilevel regulation of HR processes in genomes with greater structural and sequence complexity.
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Affiliation(s)
- Jie Liu
- Departments of Microbiology and of Molecular and Cellular Biology, University of California, Davis, CA, USA
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38
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Dobson R, Stockdale C, Lapsley C, Wilkes J, McCulloch R. Interactions among Trypanosoma brucei RAD51 paralogues in DNA repair and antigenic variation. Mol Microbiol 2011; 81:434-56. [PMID: 21615552 PMCID: PMC3170485 DOI: 10.1111/j.1365-2958.2011.07703.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Homologous recombination in Trypanosoma brucei is used for moving variant surface glycoprotein (VSG) genes into expression sites during immune evasion by antigenic variation. A major route for such VSG switching is gene conversion reactions in which RAD51, a universally conserved recombinase, catalyses homology-directed strand exchange. In any eukaryote, RAD51-directed strand exchange in vivo is mediated by further factors, including RAD51-related proteins termed Rad51 paralogues. These appear to be ubiquitously conserved, although their detailed roles in recombination remain unclear. In T. brucei, four putative RAD51 paralogue genes have been identified by sequence homology. Here we show that all four RAD51 paralogues act in DNA repair, recombination and RAD51 subnuclear dynamics, though not equivalently, while mutation of only one RAD51 paralogue gene significantly impedes VSG switching. We also show that the T. brucei RAD51 paralogues interact, and that the complexes they form may explain the distinct phenotypes of the mutants as well as observed expression interdependency. Finally, we document the Rad51 paralogues that are encoded by a wide range of protists, demonstrating that the Rad51 paralogue repertoire in T. brucei is unusually large among microbial eukaryotes and that one member of the protein family corresponds with a key, conserved eukaryotic Rad51 paralogue.
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Affiliation(s)
- Rachel Dobson
- College of Medical Veterinary and Life Sciences, University of Glasgow, Institute of Infection, Immunity and Inflammation, The Wellcome Trust Centre for Molecular Parasitology, Sir Graeme Davis Building, 120 University Place, Glasgow G128TA, UK
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39
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Ting L, Jun H, Junjie C. RAD18 lives a double life: Its implication in DNA double-strand break repair. DNA Repair (Amst) 2010; 9:1241-8. [DOI: 10.1016/j.dnarep.2010.09.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2010] [Indexed: 11/26/2022]
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40
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Somyajit K, Subramanya S, Nagaraju G. RAD51C: a novel cancer susceptibility gene is linked to Fanconi anemia and breast cancer. Carcinogenesis 2010; 31:2031-8. [PMID: 20952512 PMCID: PMC2994284 DOI: 10.1093/carcin/bgq210] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Germline mutations in many of the genes that are involved in homologous recombination (HR)-mediated DNA double-strand break repair (DSBR) are associated with various human genetic disorders and cancer. RAD51 and RAD51 paralogs are important for HR and in the maintenance of genome stability. Despite the identification of five RAD51 paralogs over a decade ago, the molecular mechanism(s) by which RAD51 paralogs regulate HR and genome maintenance remains obscure. In addition to the known roles of RAD51C in early and late stages of HR, it also contributes to activation of the checkpoint kinase CHK2. One recent study identifies biallelic mutation in RAD51C leading to Fanconi anemia-like disorder. Whereas a second study reports monoallelic mutation in RAD51C associated with increased risk of breast and ovarian cancer. These reports show RAD51C is a cancer susceptibility gene. In this review, we focus on describing the functions of RAD51C in HR, DNA damage signaling and as a tumor suppressor with an emphasis on the new roles of RAD51C unveiled by these reports.
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Affiliation(s)
- Kumar Somyajit
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
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41
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Rajesh C, Baker DK, Pierce AJ, Pittman DL. The splicing-factor related protein SFPQ/PSF interacts with RAD51D and is necessary for homology-directed repair and sister chromatid cohesion. Nucleic Acids Res 2010; 39:132-45. [PMID: 20813759 PMCID: PMC3017596 DOI: 10.1093/nar/gkq738] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
DNA double-stranded breaks (DSBs) are among the most severe forms of DNA damage and responsible for chromosomal translocations that may lead to gene fusions. The RAD51 family plays an integral role in preserving genome stability by homology directed repair of DSBs. From a proteomics screen, we recently identified SFPQ/PSF as an interacting partner with the RAD51 paralogs, RAD51D, RAD51C and XRCC2. Initially discovered as a potential RNA splicing factor, SFPQ was later shown to have homologous recombination and non-homologous end joining related activities and also to bind and modulate the function of RAD51. Here, we demonstrate that SFPQ interacts directly with RAD51D and that deficiency of both proteins confers a severe loss of cell viability, indicating a synthetic lethal relationship. Surprisingly, deficiency of SFPQ alone also leads to sister chromatid cohesion defects and chromosome instability. In addition, SFPQ was demonstrated to mediate homology directed DNA repair and DNA damage response resulting from DNA crosslinking agents, alkylating agents and camptothecin. Taken together, these data indicate that SFPQ association with the RAD51 protein complex is essential for homologous recombination repair of DNA damage and maintaining genome integrity.
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Affiliation(s)
- Changanamkandath Rajesh
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
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42
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Hartley JA, Hamaguchi A, Coffils M, Martin CRH, Suggitt M, Chen Z, Gregson SJ, Masterson LA, Tiberghien AC, Hartley JM, Pepper C, Lin TT, Fegan C, Thurston DE, Howard PW. SG2285, a novel C2-aryl-substituted pyrrolobenzodiazepine dimer prodrug that cross-links DNA and exerts highly potent antitumor activity. Cancer Res 2010; 70:6849-58. [PMID: 20660714 PMCID: PMC3533126 DOI: 10.1158/0008-5472.can-10-0790] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The pyrrolobenzodiazepines (PBD) are naturally occurring antitumor antibiotics, and a PBD dimer (SJG-136, SG2000) is in phase II trials. Many potent PBDs contain a C2-endo-exo unsaturated motif associated with the pyrrolo C-ring. The novel compound SG2202 is a PBD dimer containing this motif. SG2285 is a water-soluble prodrug of SG2202 in which two bisulfite groups inactivate the PBD N10-C11 imines. Once the bisulfites are eliminated, the imine moieties can bind covalently in the DNA minor groove, forming an interstrand cross-link. The mean in vitro cytotoxic potency of SG2285 against human tumor cell lines is GI(50) 20 pmol/L. SG2285 is highly efficient at producing DNA interstrand cross-links in cells, but they form more slowly than those produced by SG2202. Cellular sensitivity to SG2285 was primarily dependent on ERCC1 and homologous recombination repair. In primary B-cell chronic lymphocytic leukemia samples, the mean LD(50) was significantly lower than in normal age-matched B and T lymphocytes. Antitumor activity was shown in several human tumor xenograft models, including ovarian, non-small cell lung, prostate, pancreatic, and melanoma, with cures obtained in the latter model with a single dose. Further, in an advanced-stage colon model, SG2285 administered either as a single dose, or in two repeat dose schedules, was superior to irinotecan. Our findings define SG2285 as a highly active cytotoxic compound with antitumor properties desirable for further development.
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43
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Hinz JM. Role of homologous recombination in DNA interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:582-603. [PMID: 20658649 DOI: 10.1002/em.20577] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Homologous recombination repair (HRR) encompasses mechanisms that employ homologous DNA sequences as templates for repair or tolerance of a wide range of DNA lesions that inhibit DNA replication in S phase. Arguably the most imposing of these DNA lesions is that of the interstrand crosslink (ICL), consisting of a covalently attached chemical bridge between opposing DNA strands. ICL repair requires the coordinated activities of HRR and a number of proteins from other DNA repair and damage response systems, including nucleotide excision repair, base excision repair, mismatch repair, and translesion DNA synthesis (TLS). Interestingly, different organisms favor alternative methods of HRR in the ICL repair process. E. coli perform ICL repair using a homology-driven damage bypass mechanism analogous to daughter strand gap repair. Eukaryotes from yeast to humans initiate ICL repair primarily during DNA replication, relying on HRR activity to restart broken replication forks associated with double-strand break intermediates induced by nucleolytic activities of other excision repair factors. Higher eukaryotes also employ several additional factors, including members of the Fanconi anemia damage-response network, which further promote replication-associated ICL repair through the activation and coordination of various DNA excision repair, TLS, and HRR proteins. This review focuses on the proteins and general mechanisms of HRR associated with ICL repair in different model organisms.
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Affiliation(s)
- John M Hinz
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA.
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44
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Adelman CA, Boulton SJ. Metabolism of postsynaptic recombination intermediates. FEBS Lett 2010; 584:3709-16. [PMID: 20493853 DOI: 10.1016/j.febslet.2010.05.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 05/14/2010] [Indexed: 11/25/2022]
Abstract
DNA double strand breaks and blocked or collapsed DNA replication forks are potentially genotoxic lesions that can result in deletions, aneuploidy or cell death. Homologous recombination (HR) is an essential process employed during repair of these forms of damage. HR allows for accurate restoration of the damaged DNA through use of a homologous template for repair. Although inroads have been made towards understanding the mechanisms of HR, ambiguity still surrounds aspects of the process. Until recently, relatively little was known concerning metabolism of postsynaptic RAD51 filaments or how synthesis dependent strand annealing intermediates are processed. This review discusses recent findings implicating RTEL1, HELQ and the Caenorhabditis elegans RAD51 paralog RFS-1 in post-strand exchange events during HR.
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Affiliation(s)
- Carrie A Adelman
- DNA Damage Response Laboratory, Cancer Research UK, London Research Institute, South Mimms, UK
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45
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The importance of XRCC2 in RAD51-related DNA damage repair. DNA Repair (Amst) 2010; 9:517-25. [DOI: 10.1016/j.dnarep.2010.01.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/04/2009] [Accepted: 01/28/2010] [Indexed: 12/11/2022]
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46
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Compton SA, Ozgür S, Griffith JD. Ring-shaped Rad51 paralog protein complexes bind Holliday junctions and replication forks as visualized by electron microscopy. J Biol Chem 2010; 285:13349-56. [PMID: 20207730 DOI: 10.1074/jbc.m109.074286] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In mammals, there are five Rad51 paralogs that form two distinct complexes in vivo. One complex is composed of Rad51B-Rad51C-Rad51D-Xrcc2 (BCDX2) and the other Rad51C-Xrcc3 (CX3). We co-expressed and purified human BCDX2 and CX3 protein complexes from insect cells and investigated their binding preferences and structure using transmission electron microscopy (TEM). We visualized the binding of BCDX2 and CX3 to DNA templates containing replication forks and Holliday junctions, intermediates observed during DNA replication and recombination, respectively. We show that both complexes bind with exceptionally high specificity to the DNA junctions with little binding observed elsewhere on the DNAs. Further analysis of the structure of free or DNA-bound BCDX2 and CX3 complexes revealed a multimeric ring structure whose subunits are arranged into a flat disc around a central channel. This work provides the first EM visualization of BCDX2 and CX3 binding to Holliday junctions and forked DNAs and suggests the complexes form ring-shaped structures.
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Affiliation(s)
- Sarah A Compton
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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47
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Rajesh C, Gruver AM, Basrur V, Pittman DL. The interaction profile of homologous recombination repair proteins RAD51C, RAD51D and XRCC2 as determined by proteomic analysis. Proteomics 2009; 9:4071-86. [PMID: 19658102 DOI: 10.1002/pmic.200800977] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The RAD51 family of proteins is involved in homologous recombination (HR) DNA repair and maintaining chromosome integrity. To identify candidates that interact with HR proteins, the mouse RAD51C, RAD51D and XRCC2 proteins were purified using bacterial expression systems and each of them used to co-precipitate interacting partners from mouse embryonic fibroblast cellular extracts. Mass spectroscopic analysis was performed on protein bands obtained after 1-D SDS-PAGE of co-precipitation eluates from cell extracts of mitomycin C treated and untreated mouse embryonic fibroblasts. Profiling of the interacting proteins showed a clear bias toward nucleic acid binding and modification proteins. Interactions of four candidate proteins (SFPQ, NONO, MSH2 and mini chromosome maintenance protein 2) were confirmed by Western blot analysis of co-precipitation eluates and were also verified to form ex vivo complexes with RAD51D. Additional interacting proteins were associated with cell division, embryo development, protein and carbohydrate metabolism, cellular trafficking, protein synthesis, modification or folding, and cell structure or motility functions. Results from this study are an important step toward identifying interacting partners of the RAD51 paralogs and understanding the functional diversity of proteins that assist or regulate HR repair mechanisms.
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Affiliation(s)
- Changanamkandath Rajesh
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA
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48
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Gruver AM, Yard BD, McInnes C, Rajesh C, Pittman DL. Functional characterization and identification of mouse Rad51d splice variants. BMC Mol Biol 2009; 10:27. [PMID: 19327148 PMCID: PMC2667185 DOI: 10.1186/1471-2199-10-27] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 03/27/2009] [Indexed: 11/10/2022] Open
Abstract
Background The homologous recombination (HR) pathway is vital for maintaining genomic integrity through the restoration of double-stranded breaks and interstrand crosslinks. The RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2, XRCC3) are essential for this process in vertebrates, and the RAD51D paralog is unique in that it participates in both HR repair and telomere maintenance. RAD51D is also known to directly interact with the RAD51C and XRCC2 proteins. Rad51d splice variants have been reported in mouse and human tissues, supportive of a role for alternative splicing in HR regulation. The present study evaluated the interaction of the Rad51d splice isoform products with RAD51C and XRCC2 and their expression patterns. Results Yeast-2-hybrid analysis was used to determine that the Mus musculus Rad51d splice variant product RAD51DΔ7b (deleted for residues 219 through 223) was capable of interacting with both RAD51C and XRCC2 and that RAD51D+int3 interacted with XRCC2. In addition, the linker region (residues 54 through 77) of RAD51D was identified as a region that potentially mediates binding with XRCC2. Cellular localization, detected by EGFP fusion proteins, demonstrated that each of the splice variant products tested was distributed throughout the cell similar to the full-length protein. However, none of the splice variants were capable of restoring resistance of Rad51d-deficient cell lines to mitomycin C. RT-PCR expression analysis revealed that Rad51dΔ3 (deleted for exon 3) and Rad51dΔ5 (deleted for exon 5)transcripts display tissue specific expression patterns with Rad51dΔ3 being detected in each tissue except ovary and Rad51dΔ5 not detected in mammary gland and testis. These expression studies also led to the identification of two additional Rad51d ubiquitously expressed transcripts, one deleted for both exon 9 and 10 and one deleted for only exon 10. Conclusion These results suggest Rad51d alternative splice variants potentially modulate mechanisms of HR by sequestering either RAD51C or XRCC2.
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Affiliation(s)
- Aaron M Gruver
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina Campus, Columbia, SC 29208, USA.
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Takaku M, Machida S, Hosoya N, Nakayama S, Takizawa Y, Sakane I, Shibata T, Miyagawa K, Kurumizaka H. Recombination activator function of the novel RAD51- and RAD51B-binding protein, human EVL. J Biol Chem 2009; 284:14326-36. [PMID: 19329439 DOI: 10.1074/jbc.m807715200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The RAD51 protein is a central player in homologous recombinational repair. The RAD51B protein is one of five RAD51 paralogs that function in the homologous recombinational repair pathway in higher eukaryotes. In the present study, we found that the human EVL (Ena/Vasp-like) protein, which is suggested to be involved in actin-remodeling processes, unexpectedly binds to the RAD51 and RAD51B proteins and stimulates the RAD51-mediated homologous pairing and strand exchange. The EVL knockdown cells impaired RAD51 assembly onto damaged DNA after ionizing radiation or mitomycin C treatment. The EVL protein alone promotes single-stranded DNA annealing, and the recombination activities of the EVL protein are further enhanced by the RAD51B protein. The expression of the EVL protein is not ubiquitous, but it is significantly expressed in breast cancer-derived MCF7 cells. These results suggest that the EVL protein is a novel recombination factor that may be required for repairing specific DNA lesions, and that may cause tumor malignancy by its inappropriate expression.
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Affiliation(s)
- Motoki Takaku
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, and Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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Suppression of the double-strand-break-repair defect of the Saccharomyces cerevisiae rad57 mutant. Genetics 2009; 181:1195-206. [PMID: 19189942 DOI: 10.1534/genetics.109.100842] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Rad51 paralogs Rad55 and Rad57 form a heterodimer required to mediate the formation and/or stabilization of the Rad51 filament. To further characterize the function of Rad55-Rad57, we used a combination of rad57 partial suppressors to determine whether the DNA repair and recombination defects of the rad57 mutant could be completely suppressed. The combination of all suppressors, elevated temperature, srs2, rad51-I345T, and mating-type (MAT) heterozygosity resulted in almost complete suppression of the rad57 mutant defect in the recruitment of Rad51 to DNA-damaged sites, as well as survival in response to ionizing radiation and camptothecin. In a physical assay to monitor the kinetics of double-strand-break (DSB)-induced gene conversion, the rad57 mutant defect was effectively suppressed by srs2 and MAT heterozygosity, but these same suppressors failed to suppress the spontaneous recombination defect. Thus the Rad55-Rad57 heterodimer appears to have a unique function in spontaneous recombination that is not essential for DSB repair. Furthermore, we investigated the currently unknown mechanism of rad57 suppression by MAT heterozygosity and found that it is independent of DNL4.
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