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Marston AL. Chromosome segregation in budding yeast: sister chromatid cohesion and related mechanisms. Genetics 2014; 196:31-63. [PMID: 24395824 PMCID: PMC3872193 DOI: 10.1534/genetics.112.145144] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/18/2013] [Indexed: 12/28/2022] Open
Abstract
Studies on budding yeast have exposed the highly conserved mechanisms by which duplicated chromosomes are evenly distributed to daughter cells at the metaphase-anaphase transition. The establishment of proteinaceous bridges between sister chromatids, a function provided by a ring-shaped complex known as cohesin, is central to accurate segregation. It is the destruction of this cohesin that triggers the segregation of chromosomes following their proper attachment to microtubules. Since it is irreversible, this process must be tightly controlled and driven to completion. Furthermore, during meiosis, modifications must be put in place to allow the segregation of maternal and paternal chromosomes in the first division for gamete formation. Here, I review the pioneering work from budding yeast that has led to a molecular understanding of the establishment and destruction of cohesion.
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Affiliation(s)
- Adele L Marston
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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202
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De Storme N, Geelen D. The impact of environmental stress on male reproductive development in plants: biological processes and molecular mechanisms. PLANT, CELL & ENVIRONMENT 2014; 37:1-18. [PMID: 23731015 PMCID: PMC4280902 DOI: 10.1111/pce.12142] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/30/2013] [Accepted: 05/08/2013] [Indexed: 05/18/2023]
Abstract
In plants, male reproductive development is extremely sensitive to adverse climatic environments and (a)biotic stress. Upon exposure to stress, male gametophytic organs often show morphological, structural and metabolic alterations that typically lead to meiotic defects or premature spore abortion and male reproductive sterility. Depending on the type of stress involved (e.g. heat, cold, drought) and the duration of stress exposure, the underlying cellular defect is highly variable and either involves cytoskeletal alterations, tapetal irregularities, altered sugar utilization, aberrations in auxin metabolism, accumulation of reactive oxygen species (ROS; oxidative stress) or the ectopic induction of programmed cell death (PCD). In this review, we present the critically stress-sensitive stages of male sporogenesis (meiosis) and male gametogenesis (microspore development), and discuss the corresponding biological processes involved and the resulting alterations in male reproduction. In addition, this review also provides insights into the molecular and/or hormonal regulation of the environmental stress sensitivity of male reproduction and outlines putative interaction(s) between the different processes involved.
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Affiliation(s)
- Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, University of Ghent, Coupure Links, 653, B-9000, Ghent, Belgium
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203
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Lao JP, Cloud V, Huang CC, Grubb J, Thacker D, Lee CY, Dresser ME, Hunter N, Bishop DK. Meiotic crossover control by concerted action of Rad51-Dmc1 in homolog template bias and robust homeostatic regulation. PLoS Genet 2013; 9:e1003978. [PMID: 24367271 PMCID: PMC3868528 DOI: 10.1371/journal.pgen.1003978] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 10/11/2013] [Indexed: 11/18/2022] Open
Abstract
During meiosis, repair of programmed DNA double-strand breaks (DSBs) by recombination promotes pairing of homologous chromosomes and their connection by crossovers. Two DNA strand-exchange proteins, Rad51 and Dmc1, are required for meiotic recombination in many organisms. Studies in budding yeast imply that Rad51 acts to regulate Dmc1's strand exchange activity, while its own exchange activity is inhibited. However, in a dmc1 mutant, elimination of inhibitory factor, Hed1, activates Rad51's strand exchange activity and results in high levels of recombination without participation of Dmc1. Here we show that Rad51-mediated meiotic recombination is not subject to regulatory processes associated with high-fidelity chromosome segregation. These include homolog bias, a process that directs strand exchange between homologs rather than sister chromatids. Furthermore, activation of Rad51 does not effectively substitute for Dmc1's chromosome pairing activity, nor does it ensure formation of the obligate crossovers required for accurate homolog segregation. We further show that Dmc1's dominance in promoting strand exchange between homologs involves repression of Rad51's strand-exchange activity. This function of Dmc1 is independent of Hed1, but requires the meiotic kinase, Mek1. Hed1 makes a relatively minor contribution to homolog bias, but nonetheless this is important for normal morphogenesis of synaptonemal complexes and efficient crossing-over especially when DSB numbers are decreased. Super-resolution microscopy shows that Dmc1 also acts to organize discrete complexes of a Mek1 partner protein, Red1, into clusters along lateral elements of synaptonemal complexes; this activity may also contribute to homolog bias. Finally, we show that when interhomolog bias is defective, recombination is buffered by two feedback processes, one that increases the fraction of events that yields crossovers, and a second that we propose involves additional DSB formation in response to defective homolog interactions. Thus, robust crossover homeostasis is conferred by integrated regulation at initiation, strand-exchange and maturation steps of meiotic recombination. Meiosis is the specialized cell division that produces gametes by precisely reducing the chromosome copy number from two to one. Accurate segregation of homologous chromosome pairs requires they be connected by crossing-over, the precise breakage and exchange of chromosome arms that is carried out by a process called recombination. Recombination is regulated so each pair of homologous chromosomes becomes connected by at least one crossover. We studied the roles of two recombination proteins, Rad51 and Dmc1, which can act directly to join homologous DNA molecules. Our evidence supports the idea that Dmc1 is the dominant joining activity, while Rad51 acts indirectly with other proteins to support and regulate Dmc1. Furthermore, Hed1, an inhibitor of Rad51's DNA joining activity, is also shown to enhance the efficiency of crossing-over. Cells in which Rad51 is activated to promote DNA joining in place of Dmc1 have unregulated and inefficient crossing-over that often leaves chromosome pairs without the requisite crossover. Despite these defects, most cells that use Rad51 in place of Dmc1 complete meiosis and produce high levels of crossovers. Our results indicate that compensatory processes ensure that meiotic cells accumulate high levels of crossover intermediates before progressing to the first round of chromosome segregation.
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Affiliation(s)
- Jessica P. Lao
- Howard Hughes Medical Institute and Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, California, United States of America
- Genetics Graduate Group, University of California, Davis, Davis, California, United States of America
| | - Veronica Cloud
- Committee on Genetics, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
| | - Chu-Chun Huang
- Howard Hughes Medical Institute and Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, California, United States of America
| | - Jennifer Grubb
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
| | - Drew Thacker
- Weil Graduate School of Medical Sciences of Cornell University, New York, New York, United States of America
- Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Chih-Ying Lee
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Michael E. Dresser
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Neil Hunter
- Howard Hughes Medical Institute and Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, California, United States of America
- Genetics Graduate Group, University of California, Davis, Davis, California, United States of America
- Department of Molecular & Cellular Biology, University of California, Davis, Davis, California, United States of America
- Department of Cell Biology & Human Anatomy, University of California, Davis, Davis, California, United States of America
- * E-mail: (NH); (DKB)
| | - Douglas K. Bishop
- Committee on Genetics, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
- * E-mail: (NH); (DKB)
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204
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Xu X, Ball L, Chen W, Tian X, Lambrecht A, Hanna M, Xiao W. The yeast Shu complex utilizes homologous recombination machinery for error-free lesion bypass via physical interaction with a Rad51 paralogue. PLoS One 2013; 8:e81371. [PMID: 24339919 PMCID: PMC3855272 DOI: 10.1371/journal.pone.0081371] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/11/2013] [Indexed: 12/20/2022] Open
Abstract
DNA-damage tolerance (DDT) is defined as a mechanism by which eukaryotic cells resume DNA synthesis to fill the single-stranded DNA gaps left by replication-blocking lesions. Eukaryotic cells employ two different means of DDT, namely translesion DNA synthesis (TLS) and template switching, both of which are coordinately regulated through sequential ubiquitination of PCNA at the K164 residue. In the budding yeast Saccharomyces cerevisiae, the same PCNA-K164 residue can also be sumoylated, which recruits the Srs2 helicase to prevent undesired homologous recombination (HR). While the mediation of TLS by PCNA monoubiquitination has been extensively characterized, the method by which K63-linked PCNA polyubiquitination leads to template switching remains unclear. We recently identified a yeast heterotetrameric Shu complex that couples error-free DDT to HR as a critical step of template switching. Here we report that the Csm2 subunit of Shu physically interacts with Rad55, an accessory protein involved in HR. Rad55 and Rad57 are Rad51 paralogues and form a heterodimer to promote Rad51-ssDNA filament formation by antagonizing Srs2 activity. Although Rad55-Rad57 and Shu function in the same pathway and both act to inhibit Srs2 activity, Shu appears to be dedicated to error-free DDT while the Rad55-Rad57 complex is also involved in double-strand break repair. This study reveals the detailed steps of error-free lesion bypass and also brings to light an intrinsic interplay between error-free DDT and Srs2-mediated inhibition of HR.
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Affiliation(s)
- Xin Xu
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Lindsay Ball
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Wangyang Chen
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Xuelei Tian
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Amanda Lambrecht
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Michelle Hanna
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
| | - Wei Xiao
- College of Life Sciences, Capital Normal University, Beijing, China
- Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, Canada
- * E-mail:
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205
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Fornander LH, Renodon-Cornière A, Kuwabara N, Ito K, Tsutsui Y, Shimizu T, Iwasaki H, Nordén B, Takahashi M. Swi5-Sfr1 protein stimulates Rad51-mediated DNA strand exchange reaction through organization of DNA bases in the presynaptic filament. Nucleic Acids Res 2013; 42:2358-65. [PMID: 24304898 PMCID: PMC3936755 DOI: 10.1093/nar/gkt1257] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Swi5-Sfr1 heterodimer protein stimulates the Rad51-promoted DNA strand exchange reaction, a crucial step in homologous recombination. To clarify how this accessory protein acts on the strand exchange reaction, we have analyzed how the structure of the primary reaction intermediate, the Rad51/single-stranded DNA (ssDNA) complex filament formed in the presence of ATP, is affected by Swi5-Sfr1. Using flow linear dichroism spectroscopy, we observe that the nucleobases of the ssDNA are more perpendicularly aligned to the filament axis in the presence of Swi5-Sfr1, whereas the bases are more randomly oriented in the absence of Swi5-Sfr1. When using a modified version of the natural protein where the N-terminal part of Sfr1 is deleted, which has no affinity for DNA but maintained ability to stimulate the strand exchange reaction, we still observe the improved perpendicular DNA base orientation. This indicates that Swi5-Sfr1 exerts its activating effect through interaction with the Rad51 filament mainly and not with the DNA. We propose that the role of a coplanar alignment of nucleobases induced by Swi5-Sfr1 in the presynaptic Rad51/ssDNA complex is to facilitate the critical matching with an invading double-stranded DNA, hence stimulating the strand exchange reaction.
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Affiliation(s)
- Louise H Fornander
- Department of Chemical and Biological Engineering, Chalmers University of Technology, S-41296 Gothenburg, Sweden, Research Unit FRE3478, Centre National de la Recherche Scientifique & University of Nantes, F-44322 Nantes cedex 3, France, Graduate School of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan, Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, KEK, Tsukuba, 305-0801, Japan and Department of Life Science, Graduate School of Bioscience & Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
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206
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Uanschou C, Ronceret A, Von Harder M, De Muyt A, Vezon D, Pereira L, Chelysheva L, Kobayashi W, Kurumizaka H, Schlögelhofer P, Grelon M. Sufficient amounts of functional HOP2/MND1 complex promote interhomolog DNA repair but are dispensable for intersister DNA repair during meiosis in Arabidopsis. THE PLANT CELL 2013; 25:4924-40. [PMID: 24363313 PMCID: PMC3903996 DOI: 10.1105/tpc.113.118521] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During meiosis, homologous recombination (HR) is essential to repair programmed DNA double-strand breaks (DSBs), and a dedicated protein machinery ensures that the homologous chromosome is favored over the nearby sister chromatid as a repair template. The homologous-pairing protein2/meiotic nuclear division protein1 (HOP2/MND1) protein complex has been identified as a crucial factor of meiotic HR in Arabidopsis thaliana, since loss of either MND1 or HOP2 results in failure of DNA repair. We isolated two mutant alleles of HOP2 (hop2-2 and hop2-3) that retained the capacity to repair meiotic DSBs via the sister chromatid but failed to use the homologous chromosome. We show that in these alleles, the recombinases radiation sensitive51 (RAD51) and disrupted meiotic cDNA1 (DMC1) are loaded, but only the intersister DNA repair pathway is activated. The hop2-2 phenotype is correlated with a decrease in HOP2/MND1 complex abundance. In hop2-3, a truncated HOP2 protein is produced that retains its ability to bind to DMC1 and DNA but forms less stable complexes with MND1 and fails to efficiently stimulate DMC1-driven D-loop formation. Genetic analyses demonstrated that in the absence of DMC1, HOP2/MND1 is dispensable for RAD51-mediated intersister DNA repair, while in the presence of DMC1, a minimal amount of functional HOP2/MND1 is essential to drive intersister DNA repair.
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Affiliation(s)
- Clemens Uanschou
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Arnaud Ronceret
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Mona Von Harder
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Arnaud De Muyt
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Daniel Vezon
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Lucie Pereira
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Liudmila Chelysheva
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Wataru Kobayashi
- Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Peter Schlögelhofer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
- Address correspondence to
| | - Mathilde Grelon
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
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207
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Rakshambikai R, Srinivasan N, Nishant KT. Structural insights into Saccharomyces cerevisiae Msh4-Msh5 complex function using homology modeling. PLoS One 2013; 8:e78753. [PMID: 24244354 PMCID: PMC3828297 DOI: 10.1371/journal.pone.0078753] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 09/20/2013] [Indexed: 11/18/2022] Open
Abstract
The Msh4–Msh5 protein complex in eukaryotes is involved in stabilizing Holliday junctions and its progenitors to facilitate crossing over during Meiosis I. These functions of the Msh4–Msh5 complex are essential for proper chromosomal segregation during the first meiotic division. The Msh4/5 proteins are homologous to the bacterial mismatch repair protein MutS and other MutS homologs (Msh2, Msh3, Msh6). Saccharomyces cerevisiae msh4/5 point mutants were identified recently that show two fold reduction in crossing over, compared to wild-type without affecting chromosome segregation. Three distinct classes of msh4/5 point mutations could be sorted based on their meiotic phenotypes. These include msh4/5 mutations that have a) crossover and viability defects similar to msh4/5 null mutants; b) intermediate defects in crossing over and viability and c) defects only in crossing over. The absence of a crystal structure for the Msh4–Msh5 complex has hindered an understanding of the structural aspects of Msh4–Msh5 function as well as molecular explanation for the meiotic defects observed in msh4/5 mutations. To address this problem, we generated a structural model of the S. cerevisiae Msh4–Msh5 complex using homology modeling. Further, structural analysis tailored with evolutionary information is used to predict sites with potentially critical roles in Msh4–Msh5 complex formation, DNA binding and to explain asymmetry within the Msh4–Msh5 complex. We also provide a structural rationale for the meiotic defects observed in the msh4/5 point mutations. The mutations are likely to affect stability of the Msh4/5 proteins and/or interactions with DNA. The Msh4–Msh5 model will facilitate the design and interpretation of new mutational data as well as structural studies of this important complex involved in meiotic chromosome segregation.
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Affiliation(s)
| | | | - Koodali Thazath Nishant
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India
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208
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Abstract
In this review, we discuss the repair of DNA double-strand breaks (DSBs) using a homologous DNA sequence (i.e., homologous recombination [HR]), focusing mainly on yeast and mammals. We provide a historical context for the current view of HR and describe how DSBs are processed during HR as well as interactions with other DSB repair pathways. We discuss the enzymology of the process, followed by studies on DSB repair in living cells. Whenever possible, we cite both original articles and reviews to aid the reader for further studies.
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Affiliation(s)
- Maria Jasin
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center New York, New York 10065
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209
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Choi K, Zhao X, Kelly KA, Venn O, Higgins JD, Yelina NE, Hardcastle TJ, Ziolkowski PA, Copenhaver GP, Franklin FCH, McVean G, Henderson IR. Arabidopsis meiotic crossover hot spots overlap with H2A.Z nucleosomes at gene promoters. Nat Genet 2013; 45:1327-36. [PMID: 24056716 PMCID: PMC3812125 DOI: 10.1038/ng.2766] [Citation(s) in RCA: 247] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/26/2013] [Indexed: 12/13/2022]
Abstract
PRDM9 directs human meiotic crossover hot spots to intergenic sequence motifs, whereas budding yeast hot spots overlap regions of low nucleosome density (LND) in gene promoters. To investigate hot spots in plants, which lack PRDM9, we used coalescent analysis of genetic variation in Arabidopsis thaliana. Crossovers increased toward gene promoters and terminators, and hot spots were associated with active chromatin modifications, including H2A.Z, histone H3 Lys4 trimethylation (H3K4me3), LND and low DNA methylation. Hot spot-enriched A-rich and CTT-repeat DNA motifs occurred upstream and downstream, respectively, of transcriptional start sites. Crossovers were asymmetric around promoters and were most frequent over CTT-repeat motifs and H2A.Z nucleosomes. Pollen typing, segregation and cytogenetic analysis showed decreased numbers of crossovers in the arp6 H2A.Z deposition mutant at multiple scales. During meiosis, H2A.Z forms overlapping chromosomal foci with the DMC1 and RAD51 recombinases. As arp6 reduced the number of DMC1 or RAD51 foci, H2A.Z may promote the formation or processing of meiotic DNA double-strand breaks. We propose that gene chromatin ancestrally designates hot spots within eukaryotes and PRDM9 is a derived state within vertebrates.
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Affiliation(s)
- Kyuha Choi
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Xiaohui Zhao
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Krystyna A. Kelly
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Oliver Venn
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, United Kingdom
| | - James D. Higgins
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Nataliya E. Yelina
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Thomas J. Hardcastle
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Piotr A. Ziolkowski
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
- Department of Biotechnology, Adam Mickiewicz University, Umultowska 89, Poznan, Poland
| | - Gregory P. Copenhaver
- Department of Biology and the Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, North Carolina, 27599, USA
| | - F. Chris H. Franklin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Gil McVean
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford, OX3 7BN, United Kingdom
| | - Ian R. Henderson
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
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210
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Hong S, Kim KP. Shu1 promotes homolog bias of meiotic recombination in Saccharomyces cerevisiae. Mol Cells 2013; 36:446-54. [PMID: 24213600 PMCID: PMC3887942 DOI: 10.1007/s10059-013-0215-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/13/2013] [Accepted: 09/25/2013] [Indexed: 12/29/2022] Open
Abstract
Homologous recombination occurs closely between homologous chromatids with highly ordered recombinosomes through RecA homologs and mediators. The present study demonstrates this relationship during the period of "partner choice" in yeast meiotic recombination. We have examined the formation of recombination intermediates in the absence or presence of Shu1, a member of the PCSS complex, which also includes Psy3, Csm2, and Shu2. DNA physical analysis indicates that Shu1 is essential for promoting the establishment of homolog bias during meiotic homologous recombination, and the partner choice is switched by Mek1 kinase activity. Furthermore, Shu1 promotes both crossover (CO) and non-crossover (NCO) pathways of meiotic recombination. The inactivation of Mek1 kinase allows for meiotic recombination to progress efficiently, but is lost in homolog bias where most doublestrand breaks (DSBs) are repaired via stable intersister joint molecules. Moreover, the Srs2 helicase deletion cells in the budding yeast show slightly reduced COs and NCOs, and Shu1 promotes homolog bias independent of Srs2. Our findings reveal that Shu1 and Mek1 kinase activity have biochemically distinct roles in partner choice, which in turn enhances the understanding of the mechanism associated with the precondition for homolog bias.
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Affiliation(s)
- Soogil Hong
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
| | - Keun Pil Kim
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
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211
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Usui T, Kanehara Y. Elevated Rad53 kinase activity influences formation and interhomolog repair of meiotic DNA double-strand breaks in budding yeast. Biochem Biophys Res Commun 2013; 441:593-9. [PMID: 24183725 DOI: 10.1016/j.bbrc.2013.10.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 01/15/2023]
Abstract
Meiotic cells generate physiological programmed DNA double-strand breaks (DSBs) to initiate meiotic recombination. Interhomolog repair of the programmed DSBs by meiotic recombination is vital to ensure accurate chromosome segregation at meiosis I to produce normal gametes. In budding yeast, the DNA damage checkpoint kinase Rad53 is activated by DSBs which accidentally occur as DNA lesions in mitosis and meiosis; however, meiotic programmed DSBs which occur at approximately 160 loci per genome fail to activate the kinase. Thus, Rad53 activation appears to be silenced in response to meiotic programmed DSBs. In this study, to address the biological significance of Rad53's insensitivity to meiotic DSBs, we examined the effects of Rad53 overexpression on meiotic processes. The overexpression led to partial activation of Rad53, uncovering that the negative impacts of Rad53 kinase activation on meiotic progression, and formation and interhomolog repair of meiotic programmed DSBs.
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Affiliation(s)
- Takehiko Usui
- Laboratory of Genome and Chromosome Functions, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.
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212
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A new protein complex promoting the assembly of Rad51 filaments. Nat Commun 2013; 4:1676. [PMID: 23575680 DOI: 10.1038/ncomms2678] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 02/28/2013] [Indexed: 12/17/2022] Open
Abstract
During homologous recombination, eukaryotic RecA homologue Rad51 assembles into a nucleoprotein filament on single-stranded DNA to catalyse homologous pairing and DNA-strand exchange with a homologous template. Rad51 nucleoprotein filaments are highly dynamic and regulated via the coordinated actions of various accessory proteins including Rad51 mediators. Here, we identify a new Rad51 mediator complex. The PCSS complex, comprising budding yeast Psy3, Csm2, Shu1 and Shu2 proteins, binds to recombination sites and is required for Rad51 assembly and function during meiosis. Within the hetero-tetramer, Psy3-Csm2 constitutes a core sub-complex with DNA-binding activity. In vitro, purified Psy3-Csm2 stabilizes the Rad51-single-stranded DNA complex independently of nucleotide cofactor. The mechanism of Rad51 stabilization is inferred by our high-resolution crystal structure, which reveals Psy3-Csm2 to be a structural mimic of the Rad51-dimer, a fundamental unit of the Rad51-filament. Together, these results reveal a novel molecular mechanism for this class of Rad51-mediators, which includes the human Rad51 paralogues.
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213
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Morozumi Y, Ino R, Ikawa S, Mimida N, Shimizu T, Toki S, Ichikawa H, Shibata T, Kurumizaka H. Homologous pairing activities of two rice RAD51 proteins, RAD51A1 and RAD51A2. PLoS One 2013; 8:e75451. [PMID: 24124491 PMCID: PMC3790826 DOI: 10.1371/journal.pone.0075451] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/15/2013] [Indexed: 12/24/2022] Open
Abstract
In higher eukaryotes, RAD51 functions as an essential protein in homologous recombination and recombinational repair of DNA double strand breaks. During these processes, RAD51 catalyzes homologous pairing between single-stranded DNA and double-stranded DNA. Japonica cultivars of rice (Oryza sativa) encode two RAD51 proteins, RAD51A1 and RAD51A2, whereas only one RAD51 exists in yeast and mammals. However, the functional differences between RAD51A1 and RAD51A2 have not been elucidated, because their biochemical properties have not been characterized. In the present study, we purified RAD51A1 and RAD51A2, and found that RAD51A2 robustly promotes homologous pairing in vitro. RAD51A1 also possesses homologous-pairing activity, but it is only about 10% of the RAD51A2 activity. Both RAD51A1 and RAD51A2 bind to ssDNA and dsDNA, and their DNA binding strictly requires ATP, which modulates the polymer formation activities of RAD51A1 and RAD51A2. These findings suggest that although both RAD51A1 and RAD51A2 have the potential to catalyze homologous pairing, RAD51A2 may be the major recombinase in rice.
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Affiliation(s)
- Yuichi Morozumi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan
| | - Ryohei Ino
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan
| | | | - Naozumi Mimida
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Takeshi Shimizu
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Seiichi Toki
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | - Hiroaki Ichikawa
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan
| | | | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan
- * E-mail:
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214
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Danilowicz C, Peacock-Villada A, Vlassakis J, Facon A, Feinstein E, Kleckner N, Prentiss M. The differential extension in dsDNA bound to Rad51 filaments may play important roles in homology recognition and strand exchange. Nucleic Acids Res 2013; 42:526-33. [PMID: 24084082 PMCID: PMC3874182 DOI: 10.1093/nar/gkt867] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
RecA and Rad51 proteins play an important role in DNA repair and homologous recombination. For RecA, X-ray structure information and single molecule force experiments have indicated that the differential extension between the complementary strand and its Watson–Crick pairing partners promotes the rapid unbinding of non-homologous dsDNA and drives strand exchange forward for homologous dsDNA. In this work we find that both effects are also present in Rad51 protein. In particular, pulling on the opposite termini (3′ and 5′) of one of the two DNA strands in a dsDNA molecule allows dsDNA to extend along non-homologous Rad51-ssDNA filaments and remain stably bound in the extended state, but pulling on the 3′5′ ends of the complementary strand reduces the strand-exchange rate for homologous filaments. Thus, the results suggest that differential extension is also present in dsDNA bound to Rad51. The differential extension promotes rapid recognition by driving the swift unbinding of dsDNA from non-homologous Rad51-ssDNA filaments, while at the same time, reducing base pair tension due to the transfer of the Watson–Crick pairing of the complementary strand bases from the highly extended outgoing strand to the slightly less extended incoming strand, which drives strand exchange forward.
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Affiliation(s)
- Claudia Danilowicz
- Department of Physics and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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215
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Meiotic recombination in Arabidopsis is catalysed by DMC1, with RAD51 playing a supporting role. PLoS Genet 2013; 9:e1003787. [PMID: 24086145 PMCID: PMC3784562 DOI: 10.1371/journal.pgen.1003787] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/26/2013] [Indexed: 11/29/2022] Open
Abstract
Recombination establishes the chiasmata that physically link pairs of homologous chromosomes in meiosis, ensuring their balanced segregation at the first meiotic division and generating genetic variation. The visible manifestation of genetic crossing-overs, chiasmata are the result of an intricate and tightly regulated process involving induction of DNA double-strand breaks and their repair through invasion of a homologous template DNA duplex, catalysed by RAD51 and DMC1 in most eukaryotes. We describe here a RAD51-GFP fusion protein that retains the ability to assemble at DNA breaks but has lost its DNA break repair capacity. This protein fully complements the meiotic chromosomal fragmentation and sterility of Arabidopsis rad51, but not rad51 dmc1 mutants. Even though DMC1 is the only active meiotic strand transfer protein in the absence of RAD51 catalytic activity, no effect on genetic map distance was observed in complemented rad51 plants. The presence of inactive RAD51 nucleofilaments is thus able to fully support meiotic DSB repair and normal levels of crossing-over by DMC1. Our data demonstrate that RAD51 plays a supporting role for DMC1 in meiotic recombination in the flowering plant, Arabidopsis. Recombination ensures coordinated disjunction of pairs of homologous chromosomes and generates genetic exchanges in meiosis and, with some exceptions, involves the co-operation of the RAD51 and DMC1 strand-exchange proteins. We describe here a RAD51-GFP fusion protein that has lost its DNA break repair capacity but retains the ability to assemble at DNA breaks in the plant, Arabidopsis - fully complementing the meiotic chromosomal fragmentation and sterility of rad51 mutants, and this depends upon DMC1. No effect on genetic map distance was observed in complemented rad51 plants even though DMC1 is the only active strand transfer protein. The inactive RAD51 nucleofilaments are thus able to fully support meiotic DSB repair and normal levels of crossing-over by DMC1 in Arabidopsis. The RAD51-GFP protein confers a dominant-negative inhibition of RAD51-dependent mitotic recombination, while remaining fully fertile - a novel and valuable tool for research in this domain. These phenotypes are equivalent to those of the recently reported yeast rad51-II3A mutant, (Cloud et al. 2012), carrying the implication of their probable generality in other eukaryotes and extending them to a species with a very different relation between numbers of meiotic DNA double-strand breaks and crossing-overs (∼2 DSB/CO in yeast; ∼25–30 DSB/CO in Arabidopsis; ∼15 DSB/CO in mice).
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216
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Tazzite A, Jouhadi H, Hamzi K, Benider A, Nadifi S. Effect of the novel Moroccan BRCA1 and BRCA2 frameshift mutations. INDIAN JOURNAL OF HUMAN GENETICS 2013; 19:274-5. [PMID: 24019637 PMCID: PMC3758742 DOI: 10.4103/0971-6866.116114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Amal Tazzite
- Genetics and Molecular Pathology Laboratory, Medical School of Casablanca, Morocco
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217
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Jin Y, Yang H, Wei Z, Ma H, Ge X. Rice male development under drought stress: phenotypic changes and stage-dependent transcriptomic reprogramming. MOLECULAR PLANT 2013; 6:1630-45. [PMID: 23604203 DOI: 10.1093/mp/sst067] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Drought affects rice reproduction and results in severe yield loss. The developmental defects and changes of gene regulation network in reproductive tissues under drought stress are largely unknown. In this study, rice plants subjected to reproductive stage drought stress were examined for floral development and transcriptomic changes. The results showed that male fertility was dramatically affected, with differing pollen viability in flowers of the same panicle due to aberrant anther development under water stress. Examination of local starch distribution revealed that starch accumulated abnormally in terms of position and abundance in anthers of water-stressed plants. Microarray analysis using florets of different sizes identified >1000 drought-responsive genes, most of which were specifically regulated in only one or two particular sizes of florets, suggesting developmental stage-dependent responses to drought. Genes known to be involved in tapetum and/or microspore development, cell wall formation or expansion, and starch synthesis were found more frequently among the genes affected by drought than genome average, while meiosis and MADS-box genes were less frequently affected. In addition, pathways related to gibberellin acid signaling and abscisic acid catabolism were reprogrammed by drought. Our results strongly suggest interactions between reproductive development, phytohormone signaling, and carbohydrate metabolism in water-stressed plants.
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Affiliation(s)
- Yue Jin
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, China
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218
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Molecular tools for functional genomics in filamentous fungi: recent advances and new strategies. Biotechnol Adv 2013; 31:1562-74. [PMID: 23988676 DOI: 10.1016/j.biotechadv.2013.08.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 07/06/2013] [Accepted: 08/05/2013] [Indexed: 11/22/2022]
Abstract
Advances in genetic transformation techniques have made important contributions to molecular genetics. Various molecular tools and strategies have been developed for functional genomic analysis of filamentous fungi since the first DNA transformation was successfully achieved in Neurospora crassa in 1973. Increasing amounts of genomic data regarding filamentous fungi are continuously reported and large-scale functional studies have become common in a wide range of fungal species. In this review, various molecular tools used in filamentous fungi are compared and discussed, including methods for genetic transformation (e.g., protoplast transformation, electroporation, and microinjection), the construction of random mutant libraries (e.g., restriction enzyme mediated integration, transposon arrayed gene knockout, and Agrobacterium tumefaciens mediated transformation), and the analysis of gene function (e.g., RNA interference and transcription activator-like effector nucleases). We also focused on practical strategies that could enhance the efficiency of genetic manipulation in filamentous fungi, such as choosing a proper screening system and marker genes, assembling target-cassettes or vectors effectively, and transforming into strains that are deficient in the nonhomologous end joining pathway. In summary, we present an up-to-date review on the different molecular tools and latest strategies that have been successfully used in functional genomics in filamentous fungi.
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219
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Gray S, Allison RM, Garcia V, Goldman ASH, Neale MJ. Positive regulation of meiotic DNA double-strand break formation by activation of the DNA damage checkpoint kinase Mec1(ATR). Open Biol 2013; 3:130019. [PMID: 23902647 PMCID: PMC3728922 DOI: 10.1098/rsob.130019] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
During meiosis, formation and repair of programmed DNA double-strand breaks (DSBs) create genetic exchange between homologous chromosomes-a process that is critical for reductional meiotic chromosome segregation and the production of genetically diverse sexually reproducing populations. Meiotic DSB formation is a complex process, requiring numerous proteins, of which Spo11 is the evolutionarily conserved catalytic subunit. Precisely how Spo11 and its accessory proteins function or are regulated is unclear. Here, we use Saccharomyces cerevisiae to reveal that meiotic DSB formation is modulated by the Mec1(ATR) branch of the DNA damage signalling cascade, promoting DSB formation when Spo11-mediated catalysis is compromised. Activation of the positive feedback pathway correlates with the formation of single-stranded DNA (ssDNA) recombination intermediates and activation of the downstream kinase, Mek1. We show that the requirement for checkpoint activation can be rescued by prolonging meiotic prophase by deleting the NDT80 transcription factor, and that even transient prophase arrest caused by Ndt80 depletion is sufficient to restore meiotic spore viability in checkpoint mutants. Our observations are unexpected given recent reports that the complementary kinase pathway Tel1(ATM) acts to inhibit DSB formation. We propose that such antagonistic regulation of DSB formation by Mec1 and Tel1 creates a regulatory mechanism, where the absolute frequency of DSBs is maintained at a level optimal for genetic exchange and efficient chromosome segregation.
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Affiliation(s)
- Stephen Gray
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
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220
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Lamont KR, Hasham MG, Donghia NM, Branca J, Chavaree M, Chase B, Breggia A, Hedlund J, Emery I, Cavallo F, Jasin M, Rüter J, Mills KD. Attenuating homologous recombination stimulates an AID-induced antileukemic effect. ACTA ACUST UNITED AC 2013; 210:1021-33. [PMID: 23589568 PMCID: PMC3646491 DOI: 10.1084/jem.20121258] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Inhibition of the RAD51 homologous recombination factor prevents the repair of AID-initiated DNA breaks and induces apoptosis preferentially in AID-expressing human CLL. Activation-induced cytidine deaminase (AID) is critical in normal B cells to initiate somatic hypermutation and immunoglobulin class switch recombination. Accumulating evidence suggests that AID is also prooncogenic, inducing cancer-promoting mutations or chromosome rearrangements. In this context, we find that AID is expressed in >40% of primary human chronic lymphocytic leukemia (CLL) cases, consistent with other reports. Using a combination of human B lymphoid leukemia cells and mouse models, we now show that AID expression can be harnessed for antileukemic effect, after inhibition of the RAD51 homologous recombination (HR) factor with 4,4′-diisothiocyanatostilbene-2-2′-disulfonic acid (DIDS). As a proof of principle, we show that DIDS treatment inhibits repair of AID-initiated DNA breaks, induces apoptosis, and promotes cytotoxicity preferentially in AID-expressing human CLL. This reveals a novel antineoplastic role of AID that can be triggered by inhibition of HR, suggesting a potential new paradigm to treat AID-expressing tumors. Given the growing list of tumor types with aberrant AID expression, this novel therapeutic approach has potential to impact a significant patient population.
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221
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Wang X, Mbantenkhu M, Wierzbicki S, Chen XJ. Preparation of the Mgm101 recombination protein by MBP-based tagging strategy. J Vis Exp 2013. [PMID: 23851592 DOI: 10.3791/50448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The MGM101 gene was identified 20 years ago for its role in the maintenance of mitochondrial DNA. Studies from several groups have suggested that the Mgm101 protein is involved in the recombinational repair of mitochondrial DNA. Recent investigations have indicated that Mgm101 is related to the Rad52-type recombination protein family. These proteins form large oligomeric rings and promote the annealing of homologous single stranded DNA molecules. However, the characterization of Mgm101 has been hindered by the difficulty in producing the recombinant protein. Here, a reliable procedure for the preparation of recombinant Mgm101 is described. Maltose Binding Protein (MBP)-tagged Mgm101 is first expressed in Escherichia coli. The fusion protein is initially purified by amylose affinity chromatography. After being released by proteolytic cleavage, Mgm101 is separated from MBP by cationic exchange chromatography. Monodispersed Mgm101 is then obtained by size exclusion chromatography. A yield of ~0.87 mg of Mgm101 per liter of bacterial culture can be routinely obtained. The recombinant Mgm101 has minimal contamination of DNA. The prepared samples are successfully used for biochemical, structural and single particle image analyses of Mgm101. This protocol may also be used for the preparation of other large oligomeric DNA-binding proteins that may be misfolded and toxic to bacterial cells.
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Affiliation(s)
- Xiaowen Wang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, NY, USA
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222
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Abstract
Homologous recombination is associated with the dynamic assembly and disassembly of DNA-protein complexes. Assembly of a nucleoprotein filament comprising ssDNA and the RecA homolog, Rad51, is a key step required for homology search during recombination. The budding yeast Srs2 DNA translocase is known to dismantle Rad51 filament in vitro. However, there is limited evidence to support the dismantling activity of Srs2 in vivo. Here, we show that Srs2 indeed disrupts Rad51-containing complexes from chromosomes during meiosis. Overexpression of Srs2 during the meiotic prophase impairs meiotic recombination and removes Rad51 from meiotic chromosomes. This dismantling activity is specific for Rad51, as Srs2 Overexpression does not remove Dmc1 (a meiosis-specific Rad51 homolog), Rad52 (a Rad51 mediator), or replication protein A (RPA; a single-stranded DNA-binding protein). Rather, RPA replaces Rad51 under these conditions. A mutant Srs2 lacking helicase activity cannot remove Rad51 from meiotic chromosomes. Interestingly, the Rad51-binding domain of Srs2, which is critical for Rad51-dismantling activity in vitro, is not essential for this activity in vivo. Our results suggest that a precise level of Srs2, in the form of the Srs2 translocase, is required to appropriately regulate the Rad51 nucleoprotein filament dynamics during meiosis.
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223
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Yao Y, Bilichak A, Titov V, Golubov A, Kovalchuk I. Genome stability of Arabidopsis atm, ku80 and rad51b mutants: somatic and transgenerational responses to stress. PLANT & CELL PHYSIOLOGY 2013; 54:982-9. [PMID: 23574700 DOI: 10.1093/pcp/pct051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
DNA double-strand breaks (DSBs) can be repaired via two main mechanisms: non-homologous end joining (NHEJ) and homologous recombination (HR). Our previous work showed that exposure to abiotic stresses resulted in an increase in point mutation frequency (PMF) and homologous recombination frequency (HRF), and these changes were heritable. We hypothesized that mutants impaired in DSB recognition and repair would also be deficient in somatic and transgenerational changes in PMF and HRF. To test this hypothesis, we analyzed the genome stability of the Arabidopsis thaliana mutants deficient in ATM (communication between DNA strand break recognition and the repair machinery), KU80 (deficient in NHEJ) and RAD51B (deficient in HR repair) genes. We found that all three mutants exhibited higher levels of DSBs. Plants impaired in ATM had a lower spontaneous PMF and HRF, whereas ku80 plants had higher frequencies. Plants impaired in RAD51B had a lower HRF. HRF in wild-type, atm and rad51b plants increased in response to several abiotic stressors, whereas it did not increase in ku80 plants. The progeny of stressed wild-type and ku80 plants exhibited an increase in HRF in response to all stresses, and the increase was higher in ku80 plants. The progeny of atm plants showed an increase in HRF only when the parental generation was exposed to cold or flood, whereas the progeny of rad51b plants completely lacked a transgenerational increase in HRF. Our experiments showed that mutants impaired in the recognition and repair of DSBs exhibited changes in the efficiency of DNA repair as reflected by changes in strand breaks, point mutation and HRF. They also showed that the HR RAD51B protein and the protein ATM that recognized damaged DNA might play an important role in transgenerational changes in HRF.
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Affiliation(s)
- Youli Yao
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
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224
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Impaired resection of meiotic double-strand breaks channels repair to nonhomologous end joining in Caenorhabditis elegans. Mol Cell Biol 2013; 33:2732-47. [PMID: 23671188 DOI: 10.1128/mcb.00055-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Repair of double-strand DNA breaks (DSBs) by the homologous recombination (HR) pathway results in crossovers (COs) required for a successful first meiotic division. Mre11 is one member of the MRX/N (Mre11, Rad50, and Xrs2/Nbs1) complex required for meiotic DSB formation and for resection in Saccharomyces cerevisiae. In Caenorhabditis elegans, evidence for the MRX/N role in DSB resection is limited. We report the first separation-of-function allele, mre-11(iow1) in C. elegans, which is specifically defective in meiotic DSB resection but not in formation. The mre-11(iow1) mutants displayed chromosomal fragmentation and aggregation in late prophase I. Recombination intermediates and crossover formation was greatly reduced in mre-11(iow1) mutants. Irradiation-induced DSBs during meiosis failed to be repaired from early to middle prophase I in mre-11(iow1) mutants. In the absence of a functional HR, our data suggest that some DSBs in mre-11(iow1) mutants are repaired by the nonhomologous end joining (NHEJ) pathway, as removing NHEJ partially suppressed the meiotic defects shown by mre-11(iow1). In the absence of NHEJ and a functional MRX/N, meiotic DSBs are channeled to EXO-1-dependent HR repair. Overall, our analysis supports a role for MRE-11 in the resection of DSBs in middle meiotic prophase I and in blocking NHEJ.
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225
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Shinohara M, Shinohara A. Multiple pathways suppress non-allelic homologous recombination during meiosis in Saccharomyces cerevisiae. PLoS One 2013; 8:e63144. [PMID: 23646187 PMCID: PMC3639938 DOI: 10.1371/journal.pone.0063144] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 04/02/2013] [Indexed: 12/04/2022] Open
Abstract
Recombination during meiosis in the form of crossover events promotes the segregation of homologous chromosomes by providing the only physical linkage between these chromosomes. Recombination occurs not only between allelic sites but also between non-allelic (ectopic) sites. Ectopic recombination is often suppressed to prevent non-productive linkages. In this study, we examined the effects of various mutations in genes involved in meiotic recombination on ectopic recombination during meiosis. RAD24, a DNA damage checkpoint clamp-loader gene, suppressed ectopic recombination in wild type in the same pathway as RAD51. In the absence of RAD24, a meiosis-specific recA homolog, DMC1, suppressed the recombination. Homology search and strand exchange in ectopic recombination occurred when either the RAD51 or the DMC1 recA homolog was absent, but was promoted by RAD52. Unexpectedly, the zip1 mutant, which is defective in chromosome synapsis, showed a decrease, rather than an increase, in ectopic recombination. Our results provide evidence for two types of ectopic recombination: one that occurs in wild-type cells and a second that occurs predominantly when the checkpoint pathway is inactivated.
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Affiliation(s)
- Miki Shinohara
- Division of Integrated Protein Functions, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- Department of Biological Sciences, Graduate School of Science, Osaka University, Suita, Osaka, Japan
| | - Akira Shinohara
- Division of Integrated Protein Functions, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- Department of Biological Sciences, Graduate School of Science, Osaka University, Suita, Osaka, Japan
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226
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An archaeal RadA paralog influences presynaptic filament formation. DNA Repair (Amst) 2013; 12:403-13. [PMID: 23622866 DOI: 10.1016/j.dnarep.2013.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/28/2013] [Accepted: 03/02/2013] [Indexed: 11/24/2022]
Abstract
Recombinases of the RecA family play vital roles in homologous recombination, a high-fidelity mechanism to repair DNA double-stranded breaks. These proteins catalyze strand invasion and exchange after forming dynamic nucleoprotein filaments on ssDNA. Increasing evidence suggests that stabilization of these dynamic filaments is a highly conserved function across diverse species. Here, we analyze the presynaptic filament formation and DNA binding characteristics of the Sulfolobus solfataricus recombinase SsoRadA in conjunction with the SsoRadA paralog SsoRal1. In addition to constraining SsoRadA ssDNA-dependent ATPase activity, the paralog also enhances SsoRadA ssDNA binding, effectively influencing activities necessary for presynaptic filament formation. These activities result in enhanced SsoRadA-mediated strand invasion in the presence of SsoRal1 and suggest a filament stabilization function for the SsoRal1 protein.
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227
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Suyal G, Mukherjee SK, Choudhury NR. The host factor RAD51 is involved in mungbean yellow mosaic India virus (MYMIV) DNA replication. Arch Virol 2013; 158:1931-41. [PMID: 23575883 DOI: 10.1007/s00705-013-1675-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 02/12/2013] [Indexed: 11/26/2022]
Abstract
Geminiviruses replicate their single-stranded genomes with the help of only a few viral factors and various host cellular proteins primarily by rolling-circle replication (RCR) and/or recombination-dependent replication. AtRAD51 has been identified, using the phage display technique, as a host factor that potentially interacts with the Rep protein of mungbean yellow mosaic India virus (MYMIV), a member of the genus Begomovirus. In this study, we demonstrate the interaction between MYMIV Rep and a host factor, AtRAD51, using yeast two-hybrid and β-galactosidase assays, and this interaction was confirmed using a co-immunoprecipitation assay. The AtRAD51 protein complemented the rad51∆ mutation of Saccharomyces cerevisiae in an ex vivo yeast-based geminivirus DNA replication restoration assay. The semiquantitative RT-PCR and northern hybridization data revealed a higher level of expression of the Rad51 transcript in MYMIV-infected mungbean than in uninfected, healthy plants. Our findings provide evidence for a possible cross-talk between RAD51 and MYMIV Rep, which essentially controls viral DNA replication in plants, presumably in conjunction with other host factors. The present study demonstrates for the first time the involvement of a eukaryotic RAD51 protein in MYMIV replication, and this is expected to shed light on the machinery involved in begomovirus DNA replication.
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Affiliation(s)
- Geetika Suyal
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology ICGEB, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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228
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Chintapalli SV, Bhardwaj G, Babu J, Hadjiyianni L, Hong Y, Todd GK, Boosalis CA, Zhang Z, Zhou X, Ma H, Anishkin A, van Rossum DB, Patterson RL. Reevaluation of the evolutionary events within recA/RAD51 phylogeny. BMC Genomics 2013; 14:240. [PMID: 23574621 PMCID: PMC3637515 DOI: 10.1186/1471-2164-14-240] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 02/28/2013] [Indexed: 11/20/2022] Open
Abstract
Background The recA/RAD51 gene family encodes a diverse set of recombinase proteins that affect homologous recombination, DNA-repair, and genome stability. The recA gene family is expressed across all three domains of life - Eubacteria, Archaea, and Eukaryotes - and even in some viruses. To date, efforts to resolve the deep evolutionary origins of this ancient protein family have been hindered by the high sequence divergence between paralogous groups (i.e. ~30% average pairwise identity). Results Through large taxon sampling and the use of a phylogenetic algorithm designed for inferring evolutionary events in highly divergent paralogs, we obtained a robust, parsimonious and more refined phylogenetic history of the recA/RAD51 superfamily. Conclusions In summary, our model for the evolution of recA/RAD51 family provides a better understanding of the ancient origin of recA proteins and the multiple events that lead to the diversification of recA homologs in eukaryotes, including the discovery of additional RAD51 sub-families.
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Affiliation(s)
- Sree V Chintapalli
- Department of Physiology and Membrane Biology, School of Medicine, University of California-Davis, CA, USA
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229
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Du L, Luo Y. Structure of a filament of stacked octamers of human DMC1 recombinase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:382-6. [PMID: 23545642 PMCID: PMC3614161 DOI: 10.1107/s1744309113005678] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 02/26/2013] [Indexed: 11/10/2022]
Abstract
Eukaryal DMC1 proteins play a central role in homologous recombination in meiosis by assembling at the sites of programmed DNA double-strand breaks and carrying out a search for allelic DNA sequences located on homologous chromatids. They are close homologs of eukaryal Rad51 and archaeal RadA proteins and are remote homologs of bacterial RecA proteins. These recombinases (also called DNA strand-exchange proteins) promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. An octameric form of a truncated human DMC1 devoid of its small N-terminal domain (residues 1-83) has been crystallized. The structure of the truncated DMC1 octamer is similar to that of the previously reported full-length DMC1 octamer, which has disordered N-terminal domains. In each protomer, only the ATP cap regions (Asp317-Glu323) show a noticeable conformational difference. The truncated DMC1 octamers further stack with alternate polarity into a filament. Similar filamentous assemblies of DMC1 have been observed to form on DNA by electron microscopy.
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Affiliation(s)
- Liqin Du
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road Suite A3, Saskatoon, Sasktchewan S7N 5E5, Canada
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road Suite A3, Saskatoon, Sasktchewan S7N 5E5, Canada
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230
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Mbantenkhu M, Wierzbicki S, Wang X, Guo S, Wilkens S, Chen XJ. A short carboxyl-terminal tail is required for single-stranded DNA binding, higher-order structural organization, and stability of the mitochondrial single-stranded annealing protein Mgm101. Mol Biol Cell 2013; 24:1507-18. [PMID: 23536705 PMCID: PMC3655812 DOI: 10.1091/mbc.e13-01-0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mgm101 is a Rad52-type single-stranded annealing protein (SSAP) required for mitochondrial DNA (mtDNA) repair and maintenance. Structurally, Mgm101 forms large oligomeric rings. Here we determine the function(s) of a 32-amino acid carboxyl-terminal tail (Mgm101(238-269)) conserved in the Mgm101 family of proteins. Mutagenic analysis shows that Lys-253, Trp-257, Arg-259, and Tyr-268 are essential for mtDNA maintenance. Mutations in Lys-251, Arg-252, Lys-260, and Tyr-266 affect mtDNA stability at 37°C and under oxidative stress. The Y268A mutation severely affects single-stranded DNA (ssDNA) binding without altering the ring structure. Mutations in the Lys-251-Arg-252-Lys-253 positive triad also affect ssDNA binding. Moreover, the C-tail alone is sufficient to mediate ssDNA binding. Finally, we find that the W257A and R259A mutations dramatically affect the conformation and oligomeric state of Mgm101. These structural alterations correlate with protein degradation in vivo. The data thus indicate that the C-tail of Mgm101, likely displayed on the ring surface, is required for ssDNA binding, higher-order structural organization, and protein stability. We speculate that an initial electrostatic and base-stacking interaction with ssDNA could remodel ring organization. This may facilitate the formation of nucleoprotein filaments competent for mtDNA repair. These findings could have broad implications for understanding how SSAPs promote DNA repair and genome maintenance.
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Affiliation(s)
- MacMillan Mbantenkhu
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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231
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Yajima M, Suglia E, Gustafson EA, Wessel GM. Meiotic gene expression initiates during larval development in the sea urchin. Dev Dyn 2013; 242:155-63. [PMID: 23172739 PMCID: PMC3553291 DOI: 10.1002/dvdy.23904] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2012] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Meiosis is a unique mechanism in gamete production and a fundamental process shared by all sexually reproducing eukaryotes. Meiosis requires several specialized and highly conserved genes whose expression can also identify the germ cells undergoing gametogenic differentiation. Sea urchins are echinoderms, which form a phylogenetic sister group of chordates. Sea urchin embryos undergo a feeding, planktonic larval phase in which they construct an adult rudiment prior to metamorphosis. Although a series of conserved meiosis genes (e.g., dmc1, msh5, rad21, rad51, and sycp1) is expressed in sea urchin oocytes, we sought to determine when in development meiosis would first be initiated. RESULTS We surveyed the expression of several meiotic genes and their corresponding proteins in the sea urchin Strongylocentrotus purpuratus. Surprisingly, meiotic genes are highly expressed not only in ovaries but beginning in larvae. Both RNA and protein localizations strongly suggest that meiotic gene expression initiates in tissues that will eventually give rise to the adult rudiment of the late larva. CONCLUSIONS These results demonstrate that broad expression of the molecules associated with meiotic differentiation initiates prior to metamorphosis and may have additional functions in these cells, or mechanisms repressing their function, until later in development when gametogenesis begins.
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Affiliation(s)
- Mamiko Yajima
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | - Elena Suglia
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | - Eric A. Gustafson
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | - Gary M. Wessel
- MCB Department, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
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232
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Both OsRecQ1 and OsRDR1 are required for the production of small RNA in response to DNA-damage in rice. PLoS One 2013; 8:e55252. [PMID: 23383126 PMCID: PMC3559376 DOI: 10.1371/journal.pone.0055252] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 12/27/2012] [Indexed: 12/04/2022] Open
Abstract
Small RNA-mediated gene silencing pathways play important roles in the regulation of development, genome stability and various stress responses in many eukaryotes. Recently, a new type of small interfering RNAs (qiRNAs) approximately 20–21 nucleotides long in Neurospora crassa have been shown to mediate gene silencing in the DNA damage response (DDR) pathway. However, the mechanism for RNA silencing in the DDR pathway is largely unknown in plants. Here, we report that a class of small RNAs (qiRNAs) derived from rDNA was markedly induced after treatment by DNA-damaging agents [ethyl methanesulphonate (EMS and UV-C)], and that aberrant RNAs (aRNAs) as precursors were also highly induced after the DNA damage treatment in rice. However, these RNAs were completely abolished in OsRecQ1 (RecQ DNA helicase homologue) and OsRDR1 (RNA-dependent RNA polymerase homologue) mutant lines where either gene was disrupted by the insertion of rice retrotransposon Tos17 after the same treatment. DNA damage resulted in a more significant increase in cell death and a more severe inhibition of root growth in both mutant lines than in the WT. Together, these results strongly suggest that both OsRecQ1 and OsRDR1 play a pivotal role in the aRNA and qiRNA biogenesis required for the DDR and repair pathway in rice, and it may be a novel mechanism of regulation to the DDR through the production of qiRNA in plants.
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233
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Okaz E, Argüello-Miranda O, Bogdanova A, Vinod PK, Lipp JJ, Markova Z, Zagoriy I, Novak B, Zachariae W. Meiotic prophase requires proteolysis of M phase regulators mediated by the meiosis-specific APC/CAma1. Cell 2013; 151:603-18. [PMID: 23101628 DOI: 10.1016/j.cell.2012.08.044] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/24/2012] [Accepted: 08/15/2012] [Indexed: 12/13/2022]
Abstract
Whereas proliferating cells enter M phase shortly after DNA replication, the first M phase of meiosis is preceded by an extended prophase in which homologous chromosomes undergo recombination. Exit from prophase I is controlled by the recombination checkpoint (RC), which, in yeast, represses the meiosis-specific transcription factor Ndt80 required for the expression of B-type cyclins and other M phase regulators. We show that an extended prophase I additionally requires the suppression of latent, mitotic cell-cycle controls by the anaphase-promoting complex (APC/C) and its meiosis-specific activator Ama1, which trigger the degradation of M phase regulators and Ndd1, a subunit of a mitotic transcription factor. ama1Δ mutants exit from prophase I prematurely and independently of the RC, which results in recombination defects and chromosome missegregation. Thus, control of prophase I by meiotic mechanisms depends on the suppression of the alternative, mitotic mechanisms by a meiosis-specific form of the APC/C.
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Affiliation(s)
- Elwy Okaz
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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234
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Boateng KA, Bellani MA, Gregoretti IV, Pratto F, Camerini-Otero RD. Homologous pairing preceding SPO11-mediated double-strand breaks in mice. Dev Cell 2013; 24:196-205. [PMID: 23318132 DOI: 10.1016/j.devcel.2012.12.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/31/2012] [Accepted: 12/03/2012] [Indexed: 11/25/2022]
Abstract
How homologous chromosomes (homologs) find their partner, pair, and recombine during meiosis constitutes the central phenomenon in eukaryotic genetics. It is widely believed that, in most organisms, SPO11-mediated DNA double-strand breaks (DSBs) introduced during prophase I precede and are required for efficient homolog pairing. We now show that, in the mouse, a significant level of homolog pairing precedes programmed DNA cleavage. Strikingly, this early chromosome pairing still requires SPO11 but is not dependent on its ability to make DSBs or homologous recombination proteins. Intriguingly, SUN1, a protein required for telomere attachment to the nuclear envelope and for post-DSB synapsis, is also required for early pre-DSB homolog pairing. Furthermore, pre-DSB pairing at telomeres persists upon entry into prophase I and is most likely important for initiation of synapsis. Our findings suggest that the DSB-triggered homology search may mainly serve to proofread and stabilize the pre-DSB pairing of homologous chromosomes.
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Affiliation(s)
- Kingsley A Boateng
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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235
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Liu Y, Deng Y, Li G, Zhao J. Replication factor C1 (RFC1) is required for double-strand break repair during meiotic homologous recombination in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:154-165. [PMID: 22974522 DOI: 10.1111/tpj.12024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/30/2012] [Accepted: 09/11/2012] [Indexed: 06/01/2023]
Abstract
Replication factor C1 (RFC1), which is conserved in eukaryotes, is involved in DNA replication and checkpoint control. However, a RFC1 product participating in DNA repair at meiosis has not been reported in Arabidopsis. Here, we report functional characterization of AtRFC1 through analysis of the rfc1-2 mutant. The rfc1-2 mutant displayed normal vegetative growth but showed silique sterility because the male gametophyte was arrested at the uninucleus microspore stage and the female at the functional megaspore stage. Expression of AtRFC1 was concentrated in the reproductive organ primordia, meiocytes and developing gametes. Chromosome spreads showed that pairing and synapsis were normal, and the chromosomes were broken when desynapsis began at late prophase I, and chromosome fragments remained in the subsequent stages. For this reason, homologous chromosomes and sister chromatids segregated unequally, leading to pollen sterility. Immunolocalization revealed that the AtRFC1 protein localized to the chromosomes during zygotene and pachytene in wild-type but were absent in the spo11-1 mutant. The chromosome fragmentation of rfc1-2 was suppressed by spo11-1, indicating that AtRFC1 acted downstream of AtSPO11-1. The similar chromosome behavior of rad51 rfc1-2 and rad51 suggests that AtRFC1 may act with AtRAD51 in the same pathway. In summary, AtRFC1 is required for DNA double-strand break repair during meiotic homologous recombination of Arabidopsis.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yingtian Deng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Gang Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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236
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Aberrant sporogonic development of Dmc1 (a meiotic recombinase) deficient Plasmodium berghei parasites. PLoS One 2012; 7:e52480. [PMID: 23285059 PMCID: PMC3528682 DOI: 10.1371/journal.pone.0052480] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 11/19/2012] [Indexed: 11/19/2022] Open
Abstract
Background In Plasmodium, meiosis occurs in diploid zygotes as they develop into haploid motile ookinetes inside the mosquito. Further sporogonic development involves transformation of ookinetes into oocysts and formation of infective sporozoites. Methodology/Principal Findings Reverse genetics was employed to examine the role of the meiotic specific recombinase Dmc1, a bacterial RecA homolog during sporogony in Plasmodium berghei. PbDmc1 knockout (KO) parasites showed normal asexual growth kinetics compared to WT parasites; however oocyst formation in mosquitoes was reduced by 50 to 80%. Moreover, the majority of oocysts were retarded in their growth and were smaller in size compared to WT parasites. Only a few Dmc1 KO parasites completed maturation resulting in formation of fewer sporozoites which were incapable of infecting naive mice or hepatocytes in vitro. PbDmc1 KO parasites were shown to be approximately 18 times more sensitive to Bizelesin, a DNA alkylating drug compared to WT parasites as reflected by impairment of oocyst formation and sporogonic development in the mosquito vector. Conclusions/Significance Our findings suggest that PbDmc1 plays a critical role in malaria transmission biology.
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237
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Sharma D, Say AF, Ledford LL, Hughes AJ, Sehorn HA, Dwyer DS, Sehorn MG. Role of the conserved lysine within the Walker A motif of human DMC1. DNA Repair (Amst) 2012. [PMID: 23182424 DOI: 10.1016/j.dnarep.2012.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
During meiosis, the RAD51 recombinase and its meiosis-specific homolog DMC1 mediate DNA strand exchange between homologous chromosomes. The proteins form a right-handed nucleoprotein complex on ssDNA called the presynaptic filament. In an ATP-dependent manner, the presynaptic filament searches for homology to form a physical connection with the homologous chromosome. We constructed two variants of hDMC1 altering the conserved lysine residue of the Walker A motif to arginine (hDMC1(K132R)) or alanine (hDMC1(K132A)). The hDMC1 variants were expressed in Escherichia coli and purified to near homogeneity. Both hDMC1(K132R) and hDMC1(K132A) variants were devoid of ATP hydrolysis. The hDMC1(K132R) variant was attenuated for ATP binding that was partially restored by the addition of either ssDNA or calcium. The hDMC1(K132R) variant was partially capable of homologous DNA pairing and strand exchange in the presence of calcium and protecting DNA from a nuclease, while the hDMC1(K132A) variant was inactive. These results suggest that the conserved lysine of the Walker A motif in hDMC1 plays a key role in ATP binding. Furthermore, the binding of calcium and ssDNA promotes a conformational change in the ATP binding pocket of hDMC1 that promotes ATP binding. Our results provide evidence that the conserved lysine in the Walker A motif of hDMC1 is critical for ATP binding which is required for presynaptic filament formation.
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Affiliation(s)
- Deepti Sharma
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA
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238
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Zhang N, Wu X, Yang L, Xiao F, Zhang H, Zhou A, Huang Z, Huang S. FoxM1 inhibition sensitizes resistant glioblastoma cells to temozolomide by downregulating the expression of DNA-repair gene Rad51. Clin Cancer Res 2012; 18:5961-71. [PMID: 22977194 DOI: 10.1158/1078-0432.ccr-12-0039] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE Recurrent glioblastoma multiforme (GBM) is characterized by resistance to radiotherapy and chemotherapy and a poor clinical prognosis. In this study, we investigated the role of the oncogenic transcription factor FoxM1 in GBM cells' resistance to alkylator temozolomide (TMZ) and its potential molecular mechanism. EXPERIMENTAL DESIGN FoxM1 expression levels were measured by immunohistochemical analysis in 38 pairs of primary and recurrent GBM tumor samples. Expression levels were also measured in primary recurrent GBM cell lines, and their responses to TMZ were characterized. In a mechanistic study, an siRNA array was used to identify downstream genes, and a chromatin immunoprecipitation assay was used to confirm transcriptional regulation. RESULTS Recurrent tumors that were TMZ resistant expressed higher levels of FoxM1 than did primary tumors. Recurrent GBM cell lines expressed higher levels of FoxM1 and the DNA damage repair gene Rad51 and were resistant to TMZ. TMZ treatment led to increased FoxM1 and Rad51 expression. FoxM1 knockdown inhibited Rad51 expression and sensitized recurrent GBM cells to TMZ cytotoxicity. FoxM1 directly regulated Rad51 expression through 2 FoxM1-specific binding sites in its promoter. Rad51 reexpression partially rescued TMZ resistance in FoxM1-knockdown recurrent GBM cells. A direct correlation between FoxM1 expression and Rad51 expression was evident in recurrent GBM tumor samples. CONCLUSION Targeting the FoxM1-Rad51 axis may be an effective method to reverse TMZ resistance in recurrent GBM.
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Affiliation(s)
- Nu Zhang
- Department of Neurosurgery, Scientific Research Section, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, PR China
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239
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Cloud V, Chan YL, Grubb J, Budke B, Bishop DK. Rad51 is an accessory factor for Dmc1-mediated joint molecule formation during meiosis. Science 2012; 337:1222-5. [PMID: 22955832 PMCID: PMC4056682 DOI: 10.1126/science.1219379] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Meiotic recombination in budding yeast requires two RecA-related proteins, Rad51 and Dmc1, both of which form filaments on DNA capable of directing homology search and catalyzing formation of homologous joint molecules (JMs) and strand exchange. With use of a separation-of-function mutant form of Rad51 that retains filament-forming but not JM-forming activity, we show that the JM activity of Rad51 is fully dispensable for meiotic recombination. The corresponding mutation in Dmc1 causes a profound recombination defect, demonstrating Dmc1's JM activity alone is responsible for meiotic recombination. We further provide biochemical evidence that Rad51 acts with Mei5-Sae3 as a Dmc1 accessory factor. Thus, Rad51 is a multifunctional protein that catalyzes recombination directly in mitosis and indirectly, via Dmc1, during meiosis.
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Affiliation(s)
- Veronica Cloud
- Committee on Genetics, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
| | - Yuen-Ling Chan
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
| | - Jennifer Grubb
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
| | - Brian Budke
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
| | - Douglas K. Bishop
- Committee on Genetics, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
- Department of Molecular Genetics and Cell biology. University of Chicago, Cummings Life Science Center, 920 East 58 Street, Chicago IL 60637
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240
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Pan Y, Claret FX. Targeting Jab1/CSN5 in nasopharyngeal carcinoma. Cancer Lett 2012; 326:155-60. [PMID: 22867945 DOI: 10.1016/j.canlet.2012.07.033] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/26/2012] [Accepted: 07/27/2012] [Indexed: 12/12/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated head and neck cancer that is most common in eastern Asia. Epstein-Barr virus infection, environmental factors, and genetic susceptibility play important roles in NPC pathogenesis. Jab1/CSN5 is a multifunctional protein that participates in affecting integrin signaling, controlling cell proliferation and apoptosis, and regulating genomic instability and DNA repair. Correlation of Jab1/CSN5 overexpression with poor prognosis for NPC provides evidence that it is involved in the tumorigenic process. In this review, we highlight recent advances in studies of the oncogenic role of Jab1/CSN5 in NPC and its potential as a therapeutic target for this cancer.
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Affiliation(s)
- Yunbao Pan
- Department of Systems Biology, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA
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241
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Pan Y, Zhang Q, Atsaves V, Yang H, Claret FX. Suppression of Jab1/CSN5 induces radio- and chemo-sensitivity in nasopharyngeal carcinoma through changes to the DNA damage and repair pathways. Oncogene 2012; 32:2756-66. [PMID: 22797071 PMCID: PMC3566273 DOI: 10.1038/onc.2012.294] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus-associated malignancy most common in East Asia and Africa. Radiotherapy and cisplatin-based chemotherapy are the main treatment options. Unfortunately, disease response to concurrent chemoradiotherapy varies among patients with NPC, and many cases are resistant to cisplatin. Increased DNA damage repair is one of the mechanisms contributing to this resistance. Jab1/CSN5 is a multifunctional protein that participates in controlling cell proliferation and the stability of multiple proteins. Jab1 overexpression has been found to correlate with poor prognosis in several tumor types. However, the biological significance of Jab1 activity in response to cancer treatment is unclear. In this study, we used three NPC cell lines (CNE1, CNE2, and HONE1) to investigate the hypothesis that Jab1 positively regulates the DNA repair protein Rad51 and, in turn, cellular response to treatment with DNA-damaging agents such as cisplatin, ionizing radiation (IR) and ultraviolet (UV). We found that Jab1 was overexpressed in two relatively cisplatin-, IR- and UV-resistant NPC cell lines, and knocking down its expression conferred sensitivity to cisplatin, IR and UV. By contrast, exogenous Jab1 expression enhanced the resistance of NPC cells to cisplatin, IR and UV Moreover, we provide a mechanism by which Jab1 positively regulated Rad51 through p53-dependent pathway, and increased ectopic expression of Rad51 conferred cellular resistance to cisplatin, IR and UV in Jab1-deficient cells. Taken together, our findings suggest that Jab1 plays an important role in the cellular response to cisplatin and irradiation by regulating DNA damage and repair pathways. Therefore, Jab1 is a novel biomarker for predicting the outcome of patients with NPC who are treated with DNA-damaging agents.
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Affiliation(s)
- Y Pan
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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242
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Nishiguchi M, Nanjo T, Yoshida K. The effects of gamma irradiation on growth and expression of genes encoding DNA repair-related proteins in Lombardy poplar (Populus nigra var. italica). JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2012; 109:19-28. [PMID: 22245682 DOI: 10.1016/j.jenvrad.2011.12.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/28/2011] [Indexed: 05/24/2023]
Abstract
In this study, to elucidate the mechanisms of adaptation and tolerance to ionizing radiation in woody plants, we investigated the various biological effects of γ-rays on the Lombardy poplar (Populus nigra L. var. italica Du Roi). We detected abnormal leaf shape and color, fusion, distorted venation, shortened internode, fasciation and increased axillary shoots in γ-irradiated poplar plants. Acute γ-irradiation with a dose of 100Gy greatly reduced the height, stem diameter and biomass of poplar plantlets. After receiving doses of 200 and 300Gy, all the plantlets stopped growing, and then most of them withered after 4-10 weeks of γ-irradiation. Comet assays showed that nuclear DNA in suspension-cultured poplar cells had been damaged by γ-rays. To determine whether DNA repair-related proteins are involved in the response to γ-rays in Lombardy poplars, we cloned the PnRAD51, PnLIG4, PnKU70, PnXRCC4, PnPCNA and PnOGG1 cDNAs and investigated their mRNA expression. The PnRAD51, PnLIG4, PnKU70, PnXRCC4 and PnPCNA mRNAs were increased by γ-rays, but the PnOGG1 mRNA was decreased. Moreover, the expression of PnLIG4, PnKU70 and PnRAD51 was also up-regulated by Zeocin known as a DNA cleavage agent. These observations suggest that the morphogenesis, growth and protective gene expression in Lombardy poplars are severely affected by the DNA damage and unknown cellular events caused by γ-irradiation.
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Affiliation(s)
- Mitsuru Nishiguchi
- Department of Molecular and Cell Biology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan.
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243
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Guo Q, Huang X, Zhang J, Luo Y, Peng Z, Li S. Downregulation of Peroxiredoxin I by a Novel Fully Human Phage Display Recombinant Antibody Induces Apoptosis and Enhances Radiation Sensitization in A549 Lung Carcinoma Cells. Cancer Biother Radiopharm 2012; 27:307-16. [PMID: 22022930 DOI: 10.1089/cbr.2011.0989] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Qishuai Guo
- Department of Radiology, Basic Medicine College, Chongqing Medical University, Chongqing, P.R. China
| | - Xi Huang
- Department of Oncology, Hechuan District People's Hospital, Chongqing, P.R. China
| | - Jun Zhang
- Department of Radiology, Basic Medicine College, Chongqing Medical University, Chongqing, P.R. China
| | - Yi Luo
- Department of Oncology, First Affiliated Hospital, Chongqing Medical University; Chongqing, P.R. China
| | - Zhiping Peng
- Department of Radiology, Basic Medicine College, Chongqing Medical University, Chongqing, P.R. China
| | - Shaolin Li
- Department of Radiology, Basic Medicine College, Chongqing Medical University, Chongqing, P.R. China
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Du L, Luo Y. Structure of a hexameric form of RadA recombinase from Methanococcus voltae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:511-6. [PMID: 22691778 PMCID: PMC3374503 DOI: 10.1107/s1744309112010226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/07/2012] [Indexed: 11/27/2022]
Abstract
Archaeal RadA proteins are close homologues of eukaryal Rad51 and DMC1 proteins and are remote homologues of bacterial RecA proteins. For the repair of double-stranded breaks in DNA, these recombinases promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. This DNA-repair function also plays a key role in the resistance of cancer cells to chemotherapy and radiotherapy and in the resistance of bacterial cells to antibiotics. A hexameric form of a truncated Methanococcus voltae RadA protein devoid of its small N-terminal domain has been crystallized. The RadA hexamers further assemble into two-ringed assemblies. Similar assemblies can be observed in the crystals of Pyrococcus furiosus RadA and Homo sapiens DMC1. In all of these two-ringed assemblies the DNA-interacting L1 region of each protomer points inward towards the centre, creating a highly positively charged locus. The electrostatic characteristics of the central channels can be utilized in the design of novel recombinase inhibitors.
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Affiliation(s)
- Liqin Du
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Suite A3, Saskatoon, Sasktchewan S7N 5E5, Canada
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Suite A3, Saskatoon, Sasktchewan S7N 5E5, Canada
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245
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Jacquemont C, Simon JA, D'Andrea AD, Taniguchi T. Non-specific chemical inhibition of the Fanconi anemia pathway sensitizes cancer cells to cisplatin. Mol Cancer 2012; 11:26. [PMID: 22537224 PMCID: PMC3478989 DOI: 10.1186/1476-4598-11-26] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/09/2012] [Indexed: 12/15/2022] Open
Abstract
Background Platinum compounds such as cisplatin and carboplatin are DNA crosslinking agents widely used for cancer chemotherapy. However, the effectiveness of platinum compounds is often tempered by the acquisition of cellular drug resistance. Until now, no pharmacological approach has successfully overcome cisplatin resistance in cancer treatment. Since the Fanconi anemia (FA) pathway is a DNA damage response pathway required for cellular resistance to DNA interstrand crosslinking agents, identification of small molecules that inhibit the FA pathway may reveal classes of chemicals that sensitize cancer cells to cisplatin. Results Through a cell-based screening assay of over 16,000 chemicals, we identified 26 small molecules that inhibit ionizing radiation and cisplatin-induced FANCD2 foci formation, a marker of FA pathway activity, in multiple human cell lines. Most of these small molecules also compromised ionizing radiation-induced RAD51 foci formation and homologous recombination repair, indicating that they are not selective toward the regulation of FANCD2. These compounds include known inhibitors of the proteasome, cathepsin B, lysosome, CHK1, HSP90, CDK and PKC, and several uncharacterized chemicals including a novel proteasome inhibitor (Chembridge compound 5929407). Isobologram analyses demonstrated that half of the identified molecules sensitized ovarian cancer cells to cisplatin. Among them, 9 demonstrated increased efficiency toward FA pathway-proficient, cisplatin-resistant ovarian cancer cells. Six small molecules, including bortezomib (proteasome inhibitor), CA-074-Me (cathepsin B inhibitor) and 17-AAG (HSP90 inhibitor), synergized with cisplatin specifically in FA-proficient ovarian cancer cells (2008 + FANCF), but not in FA-deficient isogenic cells (2008). In addition, geldanamycin (HSP90 inhibitor) and two CHK1 inhibitors (UCN-01 and SB218078) exhibited a significantly stronger synergism with cisplatin in FA-proficient cells when compared to FA-deficient cells, suggesting a contribution of their FA pathway inhibitory activity to cisplatin sensitization. Conclusion Our findings suggest that, despite their lack of specificity, pharmaceutical inhibition of the FA pathway by bortezomib, CA-074-Me, CHK1 inhibitors or HSP90 inhibitors may be a promising strategy to sensitize cisplatin-resistant, FA pathway-proficient tumor cells to cisplatin. In addition, we identified four new small molecules which synergize with cisplatin. Further development of their analogs and evaluation of their combination with cisplatin may lead to the development of efficient cancer treatments.
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246
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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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247
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Chernenkov AY, Fedorov DV, Gracheva LM, Evstuhina TA, Kovaltsova SV, Peshekhonov VT, Fedorova IV, Korolev VG. Interactions of the HSM3 gene with genes initiating homologous recombination repair in yeast Saccharomyces cerevisiae. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412020056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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248
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Pradillo M, López E, Linacero R, Romero C, Cuñado N, Sánchez-Morán E, Santos JL. Together yes, but not coupled: new insights into the roles of RAD51 and DMC1 in plant meiotic recombination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:921-33. [PMID: 22066484 DOI: 10.1111/j.1365-313x.2011.04845.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The eukaryotic recombinases RAD51 and DMC1 are essential for DNA strand-exchange between homologous chromosomes during meiosis. RAD51 is also expressed during mitosis, and mediates homologous recombination (HR) between sister chromatids. It has been suggested that DMC1 might be involved in the switch from intersister chromatid recombination in somatic cells to interhomolog meiotic recombination. At meiosis, the Arabidopsis Atrad51 null mutant fails to synapse and has extensive chromosome fragmentation. The Atdmc1 null mutant is also asynaptic, but in this case chromosome fragmentation is absent. Thus in plants, AtDMC1 appears to be indispensable for interhomolog homologous recombination, whereas AtRAD51 seems to be more involved in intersister recombination. In this work, we have studied a new AtRAD51 knock-down mutant, Atrad51-2, which expresses only a small quantity of RAD51 protein. Atrad51-2 mutant plants are sterile and hypersensitive to DNA double-strand break induction, but their vegetative development is apparently normal. The meiotic phenotype of the mutant consists of partial synapsis, an elevated frequency of univalents, a low incidence of chromosome fragmentation and multivalent chromosome associations. Surprisingly, non-homologous chromosomes are involved in 51% of bivalents. The depletion of AtDMC1 in the Atrad51-2 background results in the loss of bivalents and in an increase of chromosome fragmentation. Our results suggest that a critical level of AtRAD51 is required to ensure the fidelity of HR during interchromosomal exchanges. Assuming the existence of asymmetrical DNA strand invasion during the initial steps of recombination, we have developed a working model in which the initial step of strand invasion is mediated by AtDMC1, with AtRAD51 required to check the fidelity of this process.
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MESH Headings
- Arabidopsis/drug effects
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis/radiation effects
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Chromosomes, Plant/genetics
- Chromosomes, Plant/metabolism
- Cisplatin/pharmacology
- DNA Breaks, Double-Stranded/radiation effects
- DNA, Plant/genetics
- DNA, Plant/metabolism
- Gamma Rays
- Gene Knockout Techniques
- Genetic Complementation Test
- Homologous Recombination
- Meiosis
- Metaphase
- Models, Genetic
- Phenotype
- Plants, Genetically Modified/drug effects
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/radiation effects
- Rad51 Recombinase/genetics
- Rad51 Recombinase/metabolism
- Rec A Recombinases/genetics
- Rec A Recombinases/metabolism
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, Madrid 28040, Spain.
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249
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Rao HBDP, Shinohara M, Shinohara A. Mps3 SUN domain is important for chromosome motion and juxtaposition of homologous chromosomes during meiosis. Genes Cells 2012; 16:1081-96. [PMID: 22017544 DOI: 10.1111/j.1365-2443.2011.01554.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In budding yeast, Mps3 is essential for duplicating the spindle pole body (SPB) and is critical for promoting chromosome motion during meiosis. It is a member of the SUN (Sad1-Unc-84) domain family of proteins that localizes to the inner nuclear envelope (NE) in many eukaryotic organisms and preferentially localizes to the SPB in vegetative growth; in meiotic prophase I, it redistributes to many sites within the NE. We constructed an mps3 mutant, mps3-sun, which completely lacks the SUN domain. Surprisingly, the mps3-sun mutation does not disrupt SPB duplication or Mps3 localization to the NE in meiosis. However, it confers several defects during meiotic prophase I including reduced chromosome motion, premature synapsis between homologous chromosomes, and reduced levels of closely juxtaposed homologous loci in pachytene. These findings suggest that in meiosis, the Mps3 SUN domain is important for modulating chromosome motion events that act in meiotic chromosome juxtaposition and by extension, promoting proper morphogenesis of the synaptonemal complex.
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Affiliation(s)
- Hanumanthu B D Prasada Rao
- Institute for Protein Research, Graduate School of Science, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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250
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Du LQ, Du XQ, Bai JQ, Wang Y, Yang QS, Wang XC, Zhao P, Wang H, Liu Q, Fan FY. Methotrexate-mediated inhibition of RAD51 expression and homologous recombination in cancer cells. J Cancer Res Clin Oncol 2012; 138:811-8. [DOI: 10.1007/s00432-011-1132-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/20/2011] [Indexed: 11/29/2022]
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