101
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Lorenz A, Mehats A, Osman F, Whitby MC. Rad51/Dmc1 paralogs and mediators oppose DNA helicases to limit hybrid DNA formation and promote crossovers during meiotic recombination. Nucleic Acids Res 2014; 42:13723-35. [PMID: 25414342 PMCID: PMC4267644 DOI: 10.1093/nar/gku1219] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 10/17/2014] [Accepted: 11/06/2014] [Indexed: 11/30/2022] Open
Abstract
During meiosis programmed DNA double-strand breaks (DSBs) are repaired by homologous recombination using the sister chromatid or the homologous chromosome (homolog) as a template. This repair results in crossover (CO) and non-crossover (NCO) recombinants. Only CO formation between homologs provides the physical linkages guiding correct chromosome segregation, which are essential to produce healthy gametes. The factors that determine the CO/NCO decision are still poorly understood. Using Schizosaccharomyces pombe as a model we show that the Rad51/Dmc1-paralog complexes Rad55-Rad57 and Rdl1-Rlp1-Sws1 together with Swi5-Sfr1 play a major role in antagonizing both the FANCM-family DNA helicase/translocase Fml1 and the RecQ-type DNA helicase Rqh1 to limit hybrid DNA formation and promote Mus81-Eme1-dependent COs. A common attribute of these protein complexes is an ability to stabilize the Rad51/Dmc1 nucleoprotein filament, and we propose that it is this property that imposes constraints on which enzymes gain access to the recombination intermediate, thereby controlling the manner in which it is processed and resolved.
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Affiliation(s)
- Alexander Lorenz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Alizée Mehats
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Fekret Osman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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102
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Abstract
Homology search and DNA strand-exchange reactions are central to homologous recombination in meiosis. During meiosis, these processes are regulated such that the probability of choosing a homolog chromatid as recombination partner is enhanced relative to that of choosing a sister chromatid. This regulatory process occurs as homologous chromosomes pair in preparation for assembly of the synaptonemal complex. Two strand-exchange proteins, Rad51 and Dmc1, cooperate in regulated homology search and strand exchange in most organisms. Here, we summarize studies on the properties of these two proteins and their accessory factors. In addition, we review current models for the assembly of meiotic strand-exchange complexes and the possible mechanisms through which the interhomolog bias of recombination partner choice is achieved.
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Affiliation(s)
- M Scott Brown
- Department of Radiation and Cellular Oncology, and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Douglas K Bishop
- Department of Radiation and Cellular Oncology, and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
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103
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Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in Saccharomyces cerevisiae. Genetics 2014; 199:399-412. [PMID: 25467183 PMCID: PMC4317650 DOI: 10.1534/genetics.114.172320] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The segregation of homologous chromosomes during the Meiosis I division requires an obligate crossover per homolog pair (crossover assurance). In Saccharomyces cerevisiae and mammals, Msh4 and Msh5 proteins stabilize Holliday junctions and its progenitors to facilitate crossing over. S. cerevisiae msh4/5 hypomorphs that reduce crossover levels up to twofold at specific loci on chromosomes VII, VIII, and XV without affecting homolog segregation were identified recently. We use the msh4–R676W hypomorph to ask if the obligate crossover is insulated from variation in crossover frequencies, using a S. cerevisiae S288c/YJM789 hybrid to map recombination genome-wide. The msh4–R676W hypomorph made on average 64 crossovers per meiosis compared to 94 made in wild type and 49 in the msh4Δ mutant confirming the defect seen at individual loci on a genome-wide scale. Crossover reductions in msh4–R676W and msh4Δ were significant across chromosomes regardless of size, unlike previous observations made at specific loci. The msh4–R676W hypomorph showed reduced crossover interference. Although crossover reduction in msh4–R676W is modest, 42% of the four viable spore tetrads showed nonexchange chromosomes. These results, along with modeling of crossover distribution, suggest the significant reduction in crossovers across chromosomes and the loss of interference compromises the obligate crossover in the msh4 hypomorph. The high spore viability of the msh4 hypomorph is maintained by efficient segregation of the natural nonexchange chromosomes. Our results suggest that variation in crossover frequencies can compromise the obligate crossover and also support a mechanistic role for interference in obligate crossover formation.
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104
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Subramanian VV, Hochwagen A. The meiotic checkpoint network: step-by-step through meiotic prophase. Cold Spring Harb Perspect Biol 2014; 6:a016675. [PMID: 25274702 DOI: 10.1101/cshperspect.a016675] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The generation of haploid gametes by meiosis is a highly conserved process for sexually reproducing organisms that, in almost all cases, involves the extensive breakage of chromosomes. These chromosome breaks occur during meiotic prophase and are essential for meiotic recombination as well as the subsequent segregation of homologous chromosomes. However, their formation and repair must be carefully monitored and choreographed with nuclear dynamics and the cell division program to avoid the creation of aberrant chromosomes and defective gametes. It is becoming increasingly clear that an intricate checkpoint-signaling network related to the canonical DNA damage response is deeply interwoven with the meiotic program and preserves order during meiotic prophase. This meiotic checkpoint network (MCN) creates a wide range of dependent relationships controlling chromosome movement, chromosome pairing, chromatin structure, and double-strand break (DSB) repair. In this review, we summarize our current understanding of the MCN. We discuss commonalities and differences in different experimental systems, with a particular emphasis on the emerging design principles that control and limit cross talk between signals to ultimately ensure the faithful inheritance of chromosomes by the next generation.
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Affiliation(s)
| | - Andreas Hochwagen
- Department of Biology, New York University, New York, New York 10003
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105
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Humphryes N, Hochwagen A. A non-sister act: recombination template choice during meiosis. Exp Cell Res 2014; 329:53-60. [PMID: 25158281 DOI: 10.1016/j.yexcr.2014.08.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/12/2014] [Accepted: 08/18/2014] [Indexed: 11/30/2022]
Abstract
Meiotic recombination has two key functions: the faithful assortment of chromosomes into gametes and the creation of genetic diversity. Both processes require that meiotic recombination occurs between homologous chromosomes, rather than sister chromatids. Accordingly, a host of regulatory factors are activated during meiosis to distinguish sisters from homologs, suppress recombination between sister chromatids and promote the chromatids of the homologous chromosome as the preferred recombination partners. Here, we discuss the recent advances in our understanding of the mechanistic basis of meiotic recombination template choice, focusing primarily on developments in the budding yeast, Saccharomyces cerevisiae, where the regulation is currently best understood.
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Affiliation(s)
- Neil Humphryes
- Department of Biology, New York University, New York, USA
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106
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Chan YL, Brown MS, Qin D, Handa N, Bishop DK. The third exon of the budding yeast meiotic recombination gene HOP2 is required for calcium-dependent and recombinase Dmc1-specific stimulation of homologous strand assimilation. J Biol Chem 2014; 289:18076-86. [PMID: 24798326 DOI: 10.1074/jbc.m114.558601] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During meiosis in Saccharomyces cerevisiae, the HOP2 and MND1 genes are essential for recombination. A previous biochemical study has shown that budding yeast Hop2-Mnd1 stimulates the activity of the meiosis-specific strand exchange protein ScDmc1 only 3-fold, whereas analogous studies using mammalian homologs show >30-fold stimulation. The HOP2 gene was recently discovered to contain a second intron that lies near the 3'-end. We show that both HOP2 introns are efficiently spliced during meiosis, forming a predominant transcript that codes for a protein with a C-terminal sequence different from that of the previously studied version of the protein. Using the newly identified HOP2 open reading frame to direct synthesis of wild type Hop2 protein, we show that the Hop2-Mnd1 heterodimer stimulated Dmc1 D-loop activity up to 30-fold, similar to the activity of mammalian Hop2-Mnd1. ScHop2-Mnd1 stimulated ScDmc1 activity in the presence of physiological (micromolar) concentrations of Ca(2+) ions, as long as Mg(2+) was also present at physiological concentrations, leading us to hypothesize that ScDmc1 protomers bind both cations in the active Dmc1 filament. Co-factor requirements and order-of-addition experiments suggested that Hop2-Mnd1-mediated stimulation of Dmc1 involves a process that follows the formation of functional Dmc1-ssDNA filaments. In dramatic contrast to mammalian orthologs, the stimulatory activity of budding yeast Hop2-Mnd1 appeared to be specific to Dmc1; we observed no Hop2-Mnd1-mediated stimulation of the other budding yeast strand exchange protein Rad51. Together, these results support previous genetic experiments indicating that Hop2-Mnd1 specifically stimulates Dmc1 during meiotic recombination in budding yeast.
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Affiliation(s)
- Yuen-Ling Chan
- From the Departments of Radiation and Cellular Oncology and
| | - M Scott Brown
- From the Departments of Radiation and Cellular Oncology and
| | - Daoming Qin
- Molecular Genetics and Cell Biology, Cummings Life Science Center, University of Chicago, Chicago, Illinois 60637 and
| | - Naofumi Handa
- the Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616
| | - Douglas K Bishop
- From the Departments of Radiation and Cellular Oncology and Molecular Genetics and Cell Biology, Cummings Life Science Center, University of Chicago, Chicago, Illinois 60637 and
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107
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Pradillo M, Varas J, Oliver C, Santos JL. On the role of AtDMC1, AtRAD51 and its paralogs during Arabidopsis meiosis. FRONTIERS IN PLANT SCIENCE 2014; 5:23. [PMID: 24596572 PMCID: PMC3925842 DOI: 10.3389/fpls.2014.00023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/20/2014] [Indexed: 05/02/2023]
Abstract
Meiotic recombination plays a critical role in achieving accurate chromosome segregation and increasing genetic diversity. Many studies, mostly in yeast, have provided important insights into the coordination and interplay between the proteins involved in the homologous recombination pathway, especially the recombinase RAD51 and the meiosis-specific DMC1. Here we summarize the current progresses on the function of both recombinases and the CX3 complex encoded by AtRAD51 paralogs, in the plant model species Arabidopsis thaliana. Similarities and differences respect to the function of these proteins in other organisms are also indicated.
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de MadridMadrid, Spain
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108
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Affiliation(s)
- Francesca Cole
- Department of Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
- * E-mail:
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109
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Kobayashi W, Sekine S, Machida S, Kurumizaka H. Green fluorescent protein fused to the C terminus of RAD51 specifically interferes with secondary DNA binding by the RAD51-ssDNA complex. Genes Genet Syst 2014; 89:169-79. [DOI: 10.1266/ggs.89.169] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Wataru Kobayashi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University
| | - Satoshi Sekine
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University
| | - Shinichi Machida
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University
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110
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Hong S, Sung Y, Yu M, Lee M, Kleckner N, Kim KP. The logic and mechanism of homologous recombination partner choice. Mol Cell 2013; 51:440-53. [PMID: 23973374 PMCID: PMC4049084 DOI: 10.1016/j.molcel.2013.08.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 05/09/2013] [Accepted: 07/17/2013] [Indexed: 11/23/2022]
Abstract
Recombinational repair of spontaneous double-strand breaks (DSBs) exhibits sister bias. DSB-initiated meiotic recombination exhibits homolog bias. Physical analysis in yeast reveals that, in both cases, the recombination reaction intrinsically gives homolog bias. From this baseline default, cohesin intervenes to confer sister bias, likely independent of cohesion. In meiosis, cohesin's sister-biasing effect is counteracted by RecA homolog Rad51 and its mediators, plus meiotic RecA homolog Dmc1, which thereby restore intrinsic homolog bias. Meiotic axis complex Red1/Mek1/Hop1 participates by cleanly switching recombination from mitotic to meiotic mode, concomitantly activating Dmc1. We propose that a Rad51/DNA filament at one DSB end captures the intact sister, creating an anchor pad. This filament extends across the DSB site on the intact partner, precluding intersister strand exchange, thus forcing use of the homolog. Cohesin and Dmc1 interactively modulate this extension, with program-appropriate effects. In accord with this model, Rad51-mediated recombination in vivo requires the presence of a sister.
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Affiliation(s)
- Soogil Hong
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
| | - Youngjin Sung
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
| | - Mi Yu
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
| | - Minsu Lee
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA02138, USA
| | - Keun P. Kim
- Department of Life Sciences, Chung-Ang University, Seoul 156-756, Korea
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