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Morciano L, Elgrabli RM, Zenvirth D, Arbel-Eden A. Homologous Recombination and Repair Functions Required for Mutagenicity during Yeast Meiosis. Genes (Basel) 2023; 14:2017. [PMID: 38002960 PMCID: PMC10671739 DOI: 10.3390/genes14112017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Several meiotic events reshape the genome prior to its transfer (via gametes) to the next generation. The occurrence of new meiotic mutations is tightly linked to homologous recombination (HR) and firmly depends on Spo11-induced DNA breaks. To gain insight into the molecular mechanisms governing mutagenicity during meiosis, we examined the timing of mutation and recombination events in cells deficient in various DNA HR-repair genes, which represent distinct functions along the meiotic recombination process. Despite sequence similarities and overlapping activities of the two DNA translocases, Rad54 and Tid1, we observed essential differences in their roles in meiotic mutation occurrence: in the absence of Rad54, meiotic mutagenicity was elevated 8-fold compared to the wild type (WT), while in the tid1Δ mutant, there were few meiotic mutations, nine percent compared to the WT. We propose that the presence of Rad54 channels recombinational repair to a less mutagenic pathway, whereas repair assisted by Tid1 is more mutagenic. A 3.5-fold increase in mutation level was observed in dmc1∆ cells, suggesting that single-stranded DNA (ssDNA) may be a potential source for mutagenicity during meiosis. Taken together, we suggest that the introduction of de novo mutations also contributes to the diversification role of meiotic recombination. These rare meiotic mutations revise genomic sequences and may contribute to long-term evolutionary changes.
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Affiliation(s)
- Liat Morciano
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Renana M. Elgrabli
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Drora Zenvirth
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
| | - Ayelet Arbel-Eden
- Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; (L.M.); (R.M.E.)
- The Medical Laboratory Sciences Department, Hadassah Academic College, Jerusalem 91010, Israel
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2
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Papaioannou IA, Dutreux F, Peltier FA, Maekawa H, Delhomme N, Bardhan A, Friedrich A, Schacherer J, Knop M. Sex without crossing over in the yeast Saccharomycodes ludwigii. Genome Biol 2021; 22:303. [PMID: 34732243 PMCID: PMC8567612 DOI: 10.1186/s13059-021-02521-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 10/20/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Intermixing of genomes through meiotic reassortment and recombination of homologous chromosomes is a unifying theme of sexual reproduction in eukaryotic organisms and is considered crucial for their adaptive evolution. Previous studies of the budding yeast species Saccharomycodes ludwigii suggested that meiotic crossing over might be absent from its sexual life cycle, which is predominated by fertilization within the meiotic tetrad. RESULTS We demonstrate that recombination is extremely suppressed during meiosis in Sd. ludwigii. DNA double-strand break formation by the conserved transesterase Spo11, processing and repair involving interhomolog interactions are required for normal meiosis but do not lead to crossing over. Although the species has retained an intact meiotic gene repertoire, genetic and population analyses suggest the exceptionally rare occurrence of meiotic crossovers in its genome. A strong AT bias of spontaneous mutations and the absence of recombination are likely responsible for its unusually low genomic GC level. CONCLUSIONS Sd. ludwigii has followed a unique evolutionary trajectory that possibly derives fitness benefits from the combination of frequent mating between products of the same meiotic event with the extreme suppression of meiotic recombination. This life style ensures preservation of heterozygosity throughout its genome and may enable the species to adapt to its environment and survive with only minimal levels of rare meiotic recombination. We propose Sd. ludwigii as an excellent natural forum for the study of genome evolution and recombination rates.
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Affiliation(s)
| | - Fabien Dutreux
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - France A. Peltier
- Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Hiromi Maekawa
- Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
- Current affiliation: Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Nicolas Delhomme
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Amit Bardhan
- Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Anne Friedrich
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
| | - Michael Knop
- Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
- German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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3
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Noncanonical Contributions of MutLγ to VDE-Initiated Crossovers During Saccharomyces cerevisiae Meiosis. G3-GENES GENOMES GENETICS 2019; 9:1647-1654. [PMID: 30902890 PMCID: PMC6505156 DOI: 10.1534/g3.119.400150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In Saccharomyces cerevisiae, the meiosis-specific axis proteins Hop1 and Red1 are present nonuniformly across the genome. In a previous study, the meiosis-specific VMA1-derived endonuclease (VDE) was used to examine Spo11-independent recombination in a recombination reporter inserted in a Hop1/Red1-enriched region (HIS4) and in a Hop1/Red1-poor region (URA3). VDE-initiated crossovers at HIS4 were mostly dependent on Mlh3, a component of the MutLγ meiotic recombination intermediate resolvase, while VDE-initiated crossovers at URA3 were mostly Mlh3-independent. These differences were abolished in the absence of the chromosome axis remodeler Pch2, and crossovers at both loci became partly Mlh3-dependent. To test the generality of these observations, we examined inserts at six additional loci that differed in terms of Hop1/Red1 enrichment, chromosome size, and distance from centromeres and telomeres. All six loci behaved similarly to URA3: the vast majority of VDE-initiated crossovers were Mlh3-independent. This indicates that, counter to previous suggestions, levels of meiotic chromosome axis protein enrichment alone do not determine which recombination pathway gives rise to crossovers during VDE-initiated meiotic recombination. In pch2∆ mutants, the fraction of VDE-induced crossovers that were Mlh3-dependent increased to levels previously observed for Spo11-initiated crossovers in pch2∆, indicating that Pch2-dependent processes play an important role in controlling the balance between MutLγ-dependent and MutLγ-independent crossovers.
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4
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Đermić E, Zahradka D, Vujaklija D, Ivanković S, Đermić D. 3'-Terminated Overhangs Regulate DNA Double-Strand Break Processing in Escherichia coli. G3 (BETHESDA, MD.) 2017; 7:3091-3102. [PMID: 28710290 PMCID: PMC5592934 DOI: 10.1534/g3.117.043521] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/11/2017] [Indexed: 01/18/2023]
Abstract
Double-strand breaks (DSBs) are lethal DNA lesions, which are repaired by homologous recombination in Escherichia coli To study DSB processing in vivo, we induced DSBs into the E. coli chromosome by γ-irradiation and measured chromosomal degradation. We show that the DNA degradation is regulated by RecA protein concentration and its rate of association with single-stranded DNA (ssDNA). RecA decreased DNA degradation in wild-type, recB, and recD strains, indicating that it is a general phenomenon in E. coli On the other hand, DNA degradation was greatly reduced and unaffected by RecA in the recB1080 mutant (which produces long overhangs) and in a strain devoid of four exonucleases that degrade a 3' tail (ssExos). 3'-5' ssExos deficiency is epistatic to RecA deficiency concerning DNA degradation, suggesting that bound RecA is shielding the 3' tail from degradation by 3'-5' ssExos. Since 3' tail preservation is common to all these situations, we infer that RecA polymerization constitutes a subset of mechanisms for preserving the integrity of 3' tails emanating from DSBs, along with 3' tail's massive length, or prevention of their degradation by inactivation of 3'-5' ssExos. Thus, we conclude that 3' overhangs are crucial in controlling the extent of DSB processing in E. coli This study suggests a regulatory mechanism for DSB processing in E. coli, wherein 3' tails impose a negative feedback loop on DSB processing reactions, specifically on helicase reloading onto dsDNA ends.
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Affiliation(s)
- Edyta Đermić
- Department of Plant Pathology, Faculty of Agriculture, University of Zagreb, 10000, Croatia
| | - Davor Zahradka
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Dušica Vujaklija
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Siniša Ivanković
- Division of Molecular Medicine, Ruđer Bošković Institute, 10000 Zagreb, Croatia
| | - Damir Đermić
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
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5
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Ivanković S, Vujaklija D, Đermić D. Nucleolytic degradation of 3'-ending overhangs is essential for DNA-end resection in RecA-loading deficient recB mutants of Escherichia coli. DNA Repair (Amst) 2017; 57:56-65. [PMID: 28689072 DOI: 10.1016/j.dnarep.2017.06.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 01/06/2023]
Abstract
Degradation of a 5'-ending strand is the hallmark of the universal process of DNA double strand break (DSB) resection, which results in creation of the central recombination intermediate, a 3'-ending overhang. Here we show that in Escherichia coli recB1080/recB1067 mutants, which are devoid of RecBCD's nuclease and RecA loading activities, degradation of the unwound 3' tail is as essential as is degradation of its 5'-ending complement. Namely, a synergistic action of ExoI, ExoVII, SbcCD and ExoX single-strand specific exonucleases (ssExos) of 3'-5' polarity was essential for preserving cell viability, DNA repair and homologous recombination in the recB1080/recB1067 mutants, to the same extent as the redundant action of 5'-tail trimming ssExos RecJ and ExoVII. recB1080 derivatives lacking 3'-5' ssExos also showed a strong induction of the SOS response and greatly increased SOS-dependent mutagenesis. Furthermore, we show that ExoI and ExoVII ssExos act synergistically in suppressing illegitimate recombination in the recB1080 mutant but not in a wt strain, while working in concert with the RecQ helicase. Remarkably, 3'-5' ssExos show synergism with RecQ helicase in the recB1080 mutant in all the assays tested. The effect of inactivation of 3'-5' ssExos in the recB1080/recB1067 mutants was much stronger than in wt, recD, and recB strains. These results demonstrate that the presence of a long, reactive 3' overhang can be as toxic for a cell as its complete absence, i.e. it may prevent DSB repair. Our results indicate that coupling of helicase and RecA-loading activity during dsDNA-end resection is crucial in avoiding the deleterious effects of a long and stabile 3' tail in E. coli.
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Affiliation(s)
- Siniša Ivanković
- Ruđer Bošković Institute, Division of Molecular Medicine, Zagreb, Croatia
| | - Dušica Vujaklija
- Ruđer Bošković Institute, Division of Molecular Biology, Zagreb, Croatia
| | - Damir Đermić
- Ruđer Bošković Institute, Division of Molecular Biology, Zagreb, Croatia.
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6
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Medhi D, Goldman AS, Lichten M. Local chromosome context is a major determinant of crossover pathway biochemistry during budding yeast meiosis. eLife 2016; 5. [PMID: 27855779 PMCID: PMC5222560 DOI: 10.7554/elife.19669] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/17/2016] [Indexed: 12/20/2022] Open
Abstract
The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions. DOI:http://dx.doi.org/10.7554/eLife.19669.001 Inside the cells of many species, double-stranded DNA is packaged together with specialized proteins to form structures called chromosomes. Breaks that span across both strands of the DNA can cause cell death because if the break is incorrectly repaired, a segment of the DNA may be lost. Cells use a process known as homologous recombination to repair such breaks correctly. This uses an undamaged DNA molecule as a template that can be copied to replace missing segments of the DNA sequence. During the repair of double-strand breaks, connections called crossovers may form. This results in the damaged and undamaged DNA molecules swapping a portion of their sequences. In meiosis, a type of cell division that produces sperm and eggs, cells deliberately break their chromosomes and then repair them using homologous recombination. The crossovers that form during this process are important for sharing chromosomes between the newly forming cells. It is crucial that the crossovers form at the right time and place along the chromosomes. Chromosomes have different structures depending on whether a cell is undergoing meiosis or normal (mitotic) cell division. This structure may influence how and where crossovers form. Enzymes called resolvases catalyze the reactions that occur during the last step in homologous recombination to generate crossovers. One particular resolvase acts only during meiosis, whereas others are active in both mitotic and meiotic cells. However, it is not known whether local features of the chromosome structure – such as the proteins packaged in the chromosome alongside the DNA – influence when and where meiotic crossover occurs. Medhi et al. have now studied how recombination occurs along different regions of the chromosomes in budding yeast cells, which undergo meiosis in a similar way to human cells. The results of the experiments reveal that the mechanism by which crossovers form depends on proteins called axis proteins, one type of which is specifically found in meiotic chromosomes. In regions that had high levels of meiotic axis proteins, crossovers mainly formed using the meiosis-specific resolvase enzyme. In regions that had low levels of meiotic axis proteins, crossovers formed using resolvases that are active in mitotic cells. Further experiments demonstrated that altering the levels of one of the meiotic axis proteins changed which resolvase was used. Overall, the results presented by Medhi et al. show that differences in chromosome structure, in particular the relative concentration of meiotic axis proteins, influence how crossovers form in yeast. Future studies will investigate whether this is observed in other organisms such as humans, and whether local chromosome structure influences other steps of homologous recombination in meiosis. DOI:http://dx.doi.org/10.7554/eLife.19669.002
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Affiliation(s)
- Darpan Medhi
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States.,Sheffield Institute for Nucleic Acids, The University of Sheffield, Sheffield, United Kingdom.,Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Alastair Sh Goldman
- Sheffield Institute for Nucleic Acids, The University of Sheffield, Sheffield, United Kingdom.,Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Michael Lichten
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
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7
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Abstract
During meiosis, numerous DNA double-strand breaks (DSBs) are formed as part of the normal developmental program. This seemingly destructive behavior is necessary for successful meiosis, since repair of the DSBs through homologous recombination (HR) helps to produce physical links between the homologous chromosomes essential for correct chromosome segregation later in meiosis. However, DSB formation at such a massive scale also introduces opportunities to generate gross chromosomal rearrangements. In this review, we explore ways in which meiotic DSBs can result in such genomic alterations.
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8
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Brown MS, Grubb J, Zhang A, Rust MJ, Bishop DK. Small Rad51 and Dmc1 Complexes Often Co-occupy Both Ends of a Meiotic DNA Double Strand Break. PLoS Genet 2015; 11:e1005653. [PMID: 26719980 PMCID: PMC4697796 DOI: 10.1371/journal.pgen.1005653] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/15/2015] [Indexed: 11/19/2022] Open
Abstract
The Eukaryotic RecA-like proteins Rad51 and Dmc1 cooperate during meiosis to promote recombination between homologous chromosomes by repairing programmed DNA double strand breaks (DSBs). Previous studies showed that Rad51 and Dmc1 form partially overlapping co-foci. Here we show these Rad51-Dmc1 co-foci are often arranged in pairs separated by distances of up to 400 nm. Paired co-foci remain prevalent when DSBs are dramatically reduced or when strand exchange or synapsis is blocked. Super-resolution dSTORM microscopy reveals that individual foci observed by conventional light microscopy are often composed of two or more substructures. The data support a model in which the two tracts of ssDNA formed by a single DSB separate from one another by distances of up to 400 nm, with both tracts often bound by one or more short (about 100 nt) Rad51 filaments and also by one or more short Dmc1 filaments.
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Affiliation(s)
- M. Scott Brown
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, 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
| | - Annie Zhang
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
| | - Michael J. Rust
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, Chicago, Illinois, United States of America
| | - Douglas K. Bishop
- Department of Molecular Genetics and Cell Biology, 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
- * E-mail:
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9
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Bélanger F, Angers JP, Fortier É, Hammond-Martel I, Costantino S, Drobetsky E, Wurtele H. Mutations in Replicative Stress Response Pathways Are Associated with S Phase-specific Defects in Nucleotide Excision Repair. J Biol Chem 2015; 291:522-37. [PMID: 26578521 DOI: 10.1074/jbc.m115.685883] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Indexed: 01/02/2023] Open
Abstract
Nucleotide excision repair (NER) is a highly conserved pathway that removes helix-distorting DNA lesions induced by a plethora of mutagens, including UV light. Our laboratory previously demonstrated that human cells deficient in either ATM and Rad3-related (ATR) kinase or translesion DNA polymerase η (i.e. key proteins that promote the completion of DNA replication in response to UV-induced replicative stress) are characterized by profound inhibition of NER exclusively during S phase. Toward elucidating the mechanistic basis of this phenomenon, we developed a novel assay to quantify NER kinetics as a function of cell cycle in the model organism Saccharomyces cerevisiae. Using this assay, we demonstrate that in yeast, deficiency of the ATR homologue Mec1 or of any among several other proteins involved in the cellular response to replicative stress significantly abrogates NER uniquely during S phase. Moreover, initiation of DNA replication is required for manifestation of this defect, and S phase NER proficiency is correlated with the capacity of individual mutants to respond to replicative stress. Importantly, we demonstrate that partial depletion of Rfa1 recapitulates defective S phase-specific NER in wild type yeast; moreover, ectopic RPA1-3 overexpression rescues such deficiency in either ATR- or polymerase η-deficient human cells. Our results strongly suggest that reduction of NER capacity during periods of enhanced replicative stress, ostensibly caused by inordinate sequestration of RPA at stalled DNA replication forks, represents a conserved feature of the multifaceted eukaryotic DNA damage response.
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Affiliation(s)
- François Bélanger
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Jean-Philippe Angers
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and the Programme de Biologie Moléculaire
| | - Émile Fortier
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Ian Hammond-Martel
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and
| | - Santiago Costantino
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département d'ophtalmologie, and
| | - Elliot Drobetsky
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Hugo Wurtele
- From the Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Québec H1T 2M4, Canada and Département de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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10
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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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11
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Rockmill B, Lefrançois P, Voelkel-Meiman K, Oke A, Roeder GS, Fung JC. High throughput sequencing reveals alterations in the recombination signatures with diminishing Spo11 activity. PLoS Genet 2013; 9:e1003932. [PMID: 24204324 PMCID: PMC3814317 DOI: 10.1371/journal.pgen.1003932] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 09/16/2013] [Indexed: 12/03/2022] Open
Abstract
Spo11 is the topoisomerase-like enzyme responsible for the induction of the meiosis-specific double strand breaks (DSBs), which initiates the recombination events responsible for proper chromosome segregation. Nineteen PCR-induced alleles of SPO11 were identified and characterized genetically and cytologically. Recombination, spore viability and synaptonemal complex (SC) formation were decreased to varying extents in these mutants. Arrest by ndt80 restored these events in two severe hypomorphic mutants, suggesting that ndt80-arrested nuclei are capable of extended DSB activity. While crossing-over, spore viability and synaptonemal complex (SC) formation defects correlated, the extent of such defects was not predictive of the level of heteroallelic gene conversions (prototrophs) exhibited by each mutant. High throughput sequencing of tetrads from spo11 hypomorphs revealed that gene conversion tracts associated with COs are significantly longer and gene conversion tracts unassociated with COs are significantly shorter than in wild type. By modeling the extent of these tract changes, we could account for the discrepancy in genetic measurements of prototrophy and crossover association. These findings provide an explanation for the unexpectedly low prototroph levels exhibited by spo11 hypomorphs and have important implications for genetic studies that assume an unbiased recovery of prototrophs, such as measurements of CO homeostasis. Our genetic and physical data support previous observations of DSB-limited meioses, in which COs are disproportionally maintained over NCOs (CO homeostasis). Most eukaryotes depend on the meiotic division to segregate each pair of chromosomes properly into their gametes. Chromosome segregation mistakes happening during meiosis are responsible for most miscarriages as well as many diseases such as Down's and Kleinfelter's syndromes in humans. Proper chromosome segregation during meiosis depends on efficient and regulated recombination events that link homologous chromosomes prior to the first meiotic division. These linkages are initiated at double-stranded breaks (DSBs) in chromosomal DNA by Spo11 and associated proteins. We isolated a valuable new set of SPO11 alleles in yeast with a wide range of Spo11 activity. Genetic analysis and high throughput sequencing of tetrads from these mutants has revealed unexpected features of meiotic recombination. First, Spo11 DSBs likely continue to form throughout a pachytene arrest in cells compromised for Spo11 activity. Second, the number of recombination initiation events in a given meiosis influences the repair outcome of those events. In addition, our results provide support for crossover homeostasis – a phenomenon in which crossovers are disproportionately maintained over other types of repair in the face of a decrease in DSBs.
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Affiliation(s)
- Beth Rockmill
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Philippe Lefrançois
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Karen Voelkel-Meiman
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Ashwini Oke
- Department of Obstetrics, Gynecology and Reproductive Sciences and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - G. Shirleen Roeder
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Jennifer C. Fung
- Department of Obstetrics, Gynecology and Reproductive Sciences and Center for Reproductive Sciences, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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12
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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: 73] [Impact Index Per Article: 6.6] [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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13
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Pch2 modulates chromatid partner choice during meiotic double-strand break repair in Saccharomyces cerevisiae. Genetics 2011; 188:511-21. [PMID: 21515575 DOI: 10.1534/genetics.111.129031] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In most organisms, the segregation of chromosomes during the first meiotic division is dependent upon at least one crossover (CO) between each pair of homologous chromosomes. COs can result from chromosome double-strand breaks (DSBs) that are induced and preferentially repaired using the homologous chromosome as a template. The PCH2 gene of budding yeast is required to establish proper meiotic chromosome axis structure and to regulate meiotic interhomolog DSB repair outcomes. These roles appear conserved in the mouse ortholog of PCH2, Trip13, which is also involved in meiotic chromosome axis organization and the regulation of DSB repair. Using a combination of genetic and physical assays to monitor meiotic DSB repair, we present data consistent with pch2Δ mutants showing defects in suppressing intersister DSB repair. These defects appear most pronounced in dmc1Δ mutants, which are defective for interhomolog repair, and explain the previously reported observation that pch2Δ dmc1Δ cells can complete meiosis. Results from genetic epistasis analyses involving spo13Δ, rad54Δ, and mek1/MEK1 alleles and an intersister recombination reporter assay are also consistent with Pch2 acting to limit intersister repair. We propose a model in which Pch2 is required to promote full Mek1 activity and thereby promotes interhomolog repair.
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14
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Zakharyevich K, Ma Y, Tang S, Hwang PYH, Boiteux S, Hunter N. Temporally and biochemically distinct activities of Exo1 during meiosis: double-strand break resection and resolution of double Holliday junctions. Mol Cell 2010; 40:1001-15. [PMID: 21172664 PMCID: PMC3061447 DOI: 10.1016/j.molcel.2010.11.032] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 09/21/2010] [Accepted: 10/21/2010] [Indexed: 01/09/2023]
Abstract
The Rad2/XPG family nuclease, Exo1, functions in a variety of DNA repair pathways. During meiosis, Exo1 promotes crossover recombination and thereby facilitates chromosome segregation at the first division. Meiotic recombination is initiated by programmed DNA double-strand breaks (DSBs). Nucleolytic resection of DSBs generates long 3' single-strand tails that undergo strand exchange with a homologous chromosome to form joint molecule (JM) intermediates. We show that meiotic DSB resection is dramatically reduced in exo1Δ mutants and test the idea that Exo1-catalyzed resection promotes crossing over by facilitating formation of crossover-specific JMs called double Holliday junctions (dHJs). Contrary to this idea, dHJs form at wild-type levels in exo1Δ mutants, implying that Exo1 has a second function that promotes resolution of dHJs into crossovers. Surprisingly, the dHJ resolution function of Exo1 is independent of its nuclease activities but requires interaction with the putative endonuclease complex, Mlh1-Mlh3. Thus, the DSB resection and procrossover functions of Exo1 during meiosis involve temporally and biochemically distinct activities.
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Affiliation(s)
- Kseniya Zakharyevich
- Howard Hughes Medical Institute and the Departments of Microbiology, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California Davis, One Shields Ave., Davis, CA 95616, USA
| | - Yunmei Ma
- Howard Hughes Medical Institute and the Departments of Microbiology, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California Davis, One Shields Ave., Davis, CA 95616, USA
| | - Shangming Tang
- Howard Hughes Medical Institute and the Departments of Microbiology, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California Davis, One Shields Ave., Davis, CA 95616, USA
| | - Patty Yi-Hwa Hwang
- Howard Hughes Medical Institute and the Departments of Microbiology, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California Davis, One Shields Ave., Davis, CA 95616, USA
| | - Serge Boiteux
- CEA SDV/IRCM UMR217 CNRS Radiobiologie Moléculaire et Cellulaire, CEA Fontenay aux Roses, France
| | - Neil Hunter
- Howard Hughes Medical Institute and the Departments of Microbiology, Molecular & Cellular Biology and Cell Biology & Human Anatomy, University of California Davis, One Shields Ave., Davis, CA 95616, USA
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15
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Hodgson A, Terentyev Y, Johnson RA, Bishop-Bailey A, Angevin T, Croucher A, Goldman ASH. Mre11 and Exo1 contribute to the initiation and processivity of resection at meiotic double-strand breaks made independently of Spo11. DNA Repair (Amst) 2010; 10:138-48. [PMID: 21146476 DOI: 10.1016/j.dnarep.2010.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/29/2010] [Accepted: 11/18/2010] [Indexed: 11/18/2022]
Abstract
During meiosis DNA double-strand breaks (DSBs) are induced and repaired by homologous recombination to create gene conversion and crossover products. Mostly these DSBs are made by Spo11, which covalently binds to the DSB ends. More rarely in Saccharomyces cerevisiae, other meiotic DSBs are formed by self-homing endonucleases such as VDE, which is site specific and does not covalently bind to the DSB ends. We have used experimentally located VDE-DSB sites to analyse an intermediate step in homologous recombination, resection of the single-strand ending 5' at the DSB site. Analysis of strains with different mutant alleles of MRE11 (mre11-58S and mre11-H125N) and deleted for EXO1 indicated that these two nucleases make significant contributions to repair of VDE-DSBs. Physical analysis of single-stranded repair intermediates indicates that efficient initiation and processivity of resection at VDE-DSBs require both Mre11 and Exo1, with loss of function for either protein causing severe delay in resection. We propose that these experiments model what happens at Spo11-DSBs after removal of the covalently bound protein, and that Mre11 and Exo1 are the major nucleases involved in creating resection tracts of widely varying lengths typical of meiotic recombination.
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Affiliation(s)
- Adam Hodgson
- Department of Molecular Biology & Biotechnology, Krebs Institute, The University of Sheffield, Sheffield, UK
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16
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Frequent and efficient use of the sister chromatid for DNA double-strand break repair during budding yeast meiosis. PLoS Biol 2010; 8:e1000520. [PMID: 20976044 PMCID: PMC2957403 DOI: 10.1371/journal.pbio.1000520] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/02/2010] [Indexed: 01/07/2023] Open
Abstract
Studies of DNA double-strand break repair during meiosis reveal that a substantial fraction of recombination occurs between sister chromatids. Recombination between homologous chromosomes of different parental origin (homologs) is necessary for their accurate segregation during meiosis. It has been suggested that meiotic inter-homolog recombination is promoted by a barrier to inter-sister-chromatid recombination, imposed by meiosis-specific components of the chromosome axis. Consistent with this, measures of Holliday junction–containing recombination intermediates (joint molecules [JMs]) show a strong bias towards inter-homolog and against inter-sister JMs. However, recombination between sister chromatids also has an important role in meiosis. The genomes of diploid organisms in natural populations are highly polymorphic for insertions and deletions, and meiotic double-strand breaks (DSBs) that form within such polymorphic regions must be repaired by inter-sister recombination. Efforts to study inter-sister recombination during meiosis, in particular to determine recombination frequencies and mechanisms, have been constrained by the inability to monitor the products of inter-sister recombination. We present here molecular-level studies of inter-sister recombination during budding yeast meiosis. We examined events initiated by DSBs in regions that lack corresponding sequences on the homolog, and show that these DSBs are efficiently repaired by inter-sister recombination. This occurs with the same timing as inter-homolog recombination, but with reduced (2- to 3-fold) yields of JMs. Loss of the meiotic-chromosome-axis-associated kinase Mek1 accelerates inter-sister DSB repair and markedly increases inter-sister JM frequencies. Furthermore, inter-sister JMs formed in mek1Δ mutants are preferentially lost, while inter-homolog JMs are maintained. These findings indicate that inter-sister recombination occurs frequently during budding yeast meiosis, with the possibility that up to one-third of all recombination events occur between sister chromatids. We suggest that a Mek1-dependent reduction in the rate of inter-sister repair, combined with the destabilization of inter-sister JMs, promotes inter-homolog recombination while retaining the capacity for inter-sister recombination when inter-homolog recombination is not possible. In diploid organisms, which contain two parental sets of chromosomes, double-stranded breaks in DNA can be repaired by recombination, either with a copy of the chromosome produced by replication (the sister chromatid), or with either chromatid of the other parental chromosome (the homolog). During meiosis, recombination with the homolog ensures faithful segregation of chromosomes to gametes (sperm or egg). It has been suggested that use of the spatially distant homolog, as opposed to the nearby sister chromatid, results from a meiosis-specific barrier to recombination between sister chromatids. However, there are situations where meiotic recombination must occur between sister chromatids, such as when recombination initiates in sequences that are absent from the homolog. By studying such a situation, we show that meiotic recombination with the sister chromatid occurs with similar timing and efficiency as recombination with the homolog. Further analysis indicates that inter-sister recombination is more common than was previously thought, although still far less prevalent than in somatic cells, where inter-sister recombination predominates. We suggest that meiosis-specific factors act to roughly equalize repair from the sister and homolog, which both allows the establishment of physical connections between homologs and ensures timely repair of breaks incurred in regions lacking corresponding sequences on the homolog.
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17
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Callender TL, Hollingsworth NM. Mek1 suppression of meiotic double-strand break repair is specific to sister chromatids, chromosome autonomous and independent of Rec8 cohesin complexes. Genetics 2010; 185:771-82. [PMID: 20421598 PMCID: PMC2900162 DOI: 10.1534/genetics.110.117523] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 04/21/2010] [Indexed: 11/18/2022] Open
Abstract
During meiosis, recombination is directed to occur between homologous chromosomes to create connections necessary for proper segregation at meiosis I. Partner choice is determined at the time of strand invasion and is mediated by two recombinases: Rad51 and the meiosis-specific Dmc1. In budding yeast, interhomolog bias is created in part by the activity of a meiosis-specific kinase, Mek1, which is localized to the protein cores of condensed sister chromatids. Analysis of meiotic double-strand break (DSB) repair in haploid and disomic haploid strains reveals that Mek1 suppresses meiotic intersister DSB repair by working directly on sister chromatids. Rec8 cohesin complexes are not required, however, either for suppression of intersister DSB repair or for the repair itself. Regulation of DSB repair in meiosis is chromosome autonomous such that unrepaired breaks on haploid chromosomes do not prevent interhomolog repair between disomic homologs. The pattern of DSB repair in haploids containing Dmc1 and/or Rad51 indicates that Mek1 acts on Rad51-specific recombination processes.
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Affiliation(s)
| | - Nancy M. Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215
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18
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Lydeard JR, Lipkin-Moore Z, Jain S, Eapen VV, Haber JE. Sgs1 and exo1 redundantly inhibit break-induced replication and de novo telomere addition at broken chromosome ends. PLoS Genet 2010; 6:e1000973. [PMID: 20523895 PMCID: PMC2877739 DOI: 10.1371/journal.pgen.1000973] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/29/2010] [Indexed: 12/22/2022] Open
Abstract
In budding yeast, an HO endonuclease-inducible double-strand break (DSB) is efficiently repaired by several homologous recombination (HR) pathways. In contrast to gene conversion (GC), where both ends of the DSB can recombine with the same template, break-induced replication (BIR) occurs when only the centromere-proximal end of the DSB can locate homologous sequences. Whereas GC results in a small patch of new DNA synthesis, BIR leads to a nonreciprocal translocation. The requirements for completing BIR are significantly different from those of GC, but both processes require 5′ to 3′ resection of DSB ends to create single-stranded DNA that leads to formation of a Rad51 filament required to initiate HR. Resection proceeds by two pathways dependent on Exo1 or the BLM homolog, Sgs1. We report that Exo1 and Sgs1 each inhibit BIR but have little effect on GC, while overexpression of either protein severely inhibits BIR. In contrast, overexpression of Rad51 markedly increases the efficiency of BIR, again with little effect on GC. In sgs1Δ exo1Δ strains, where there is little 5′ to 3′ resection, the level of BIR is not different from either single mutant; surprisingly, there is a two-fold increase in cell viability after HO induction whereby 40% of all cells survive by formation of a new telomere within a few kb of the site of DNA cleavage. De novo telomere addition is rare in wild-type, sgs1Δ, or exo1Δ cells. In sgs1Δ exo1Δ, repair by GC is severely inhibited, but cell viaiblity remains high because of new telomere formation. These data suggest that the extensive 5′ to 3′ resection that occurs before the initiation of new DNA synthesis in BIR may prevent efficient maintenance of a Rad51 filament near the DSB end. The severe constraint on 5′ to 3′ resection, which also abrogates activation of the Mec1-dependent DNA damage checkpoint, permits an unprecedented level of new telomere addition. A chromosomal double-strand break (DSB) poses a severe threat to genome integrity, and budding yeast cells use several homologous recombination mechanisms to repair the break. In gene conversion (GC), both ends of the DSB share homology to an intact donor locus, and the break is repaired by copying the donor to create a small patch of new DNA synthesis. In break-induced replication (BIR), only one side of the DSB shares homology to a donor, and repair involves assembly of a recombination-dependent replication fork that copies sequences to the end of the template chromosome, yielding a nonreciprocal translocation. Both processes require that the DSB ends be resected by 5′ to 3′ exonucleases, involving several proteins or protein complexes, including Exo1 and Sgs1-Rmi1-Top3-Dna2. We report that ectopic BIR is inhibited independently by Sgs1 and Exo1 and that overexpression of Rad51 recombinase further improves BIR, while GC is largely unaffected. Surprisingly, when both Sgs1 and Exo1 are deleted, and resection is severely impaired, half of the cells acquire new telomeres rather than completing BIR or GC. New telomere addition appears to result from the lack of resection itself and from the fact that, without resection, the Mec1 (ATR) DNA damage checkpoint fails to inactivate the Pif1 helicase that discourages new telomere formation.
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Affiliation(s)
- John R. Lydeard
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Zachary Lipkin-Moore
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Suvi Jain
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Vinay V. Eapen
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - James E. Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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19
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Terentyev Y, Johnson R, Neale MJ, Khisroon M, Bishop-Bailey A, Goldman ASH. Evidence that MEK1 positively promotes interhomologue double-strand break repair. Nucleic Acids Res 2010; 38:4349-60. [PMID: 20223769 PMCID: PMC2910038 DOI: 10.1093/nar/gkq137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
During meiosis there is an imperative to create sufficient crossovers for homologue segregation. This can be achieved during repair of programmed DNA double-strand breaks (DSBs), which are biased towards using a homologue rather than sister chromatid as a repair template. Various proteins contribute to this bias, one of which is a meiosis specific kinase Mek1. It has been proposed that Mek1 establishes the bias by creating a barrier to sister chromatid repair, as distinct from enforcing strand invasion with the homologue. We looked for evidence that Mek1 positively stimulates strand invasion of the homologue. This was done by analysing repair of DSBs induced by the VMA1-derived endonuclease (VDE) and flanked by directly repeated sequences that can be used for intrachromatid single-strand annealing (SSA). SSA competes with interhomologue strand invasion significantly more successfully when Mek1 function is lost. We suggest the increase in intrachromosomal SSA reflects an opportunistic default repair pathway due to loss of a MEK1 stimulated bias for strand invasion of the homologous chromosome. Making use of an inhibitor sensitive mek1-as1 allele, we found that Mek1 function influences the repair pathway throughout the first4–5 h of meiosis. Perhaps reflecting a particular need to create bias for successful interhomologue events before chromosome pairing is complete.
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Affiliation(s)
- Yaroslav Terentyev
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, UK
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20
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Regulation of meiotic recombination via Mek1-mediated Rad54 phosphorylation. Mol Cell 2010; 36:393-404. [PMID: 19917248 DOI: 10.1016/j.molcel.2009.09.029] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 07/16/2009] [Accepted: 08/14/2009] [Indexed: 12/20/2022]
Abstract
A preference for homologs over sister chromatids in homologous recombination is a fundamental difference in meiotic versus mitotic cells. In budding yeast, the bias for interhomolog recombination in meiosis requires the Dmc1 recombinase and the meiosis-specific kinase Mek1, which suppresses engagement of sister chromatids by the mitotic recombinase Rad51. Here, a combination of proteomic, biochemical, and genetic approaches has identified an additional role for Mek1 in inhibiting the activity of the Rad51 recombinase through phosphorylation of its binding partner, Rad54. Rad54 phosphorylation of threonine 132 attenuates complex formation with Rad51, and a negative charge at this position reduces Rad51 function in vitro and in vivo. Thus, Mek1 phosphorylation provides a dynamic means of controlling recombination partner choice in meiosis in two ways: (1) it reduces Rad51 activity through inhibition of Rad51/Rad54 complex formation, and (2) it suppresses Rad51-mediated strand invasion of sister chromatids via a Rad54-independent mechanism.
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21
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Westmoreland J, Ma W, Yan Y, Van Hulle K, Malkova A, Resnick MA. RAD50 is required for efficient initiation of resection and recombinational repair at random, gamma-induced double-strand break ends. PLoS Genet 2009; 5:e1000656. [PMID: 19763170 PMCID: PMC2734177 DOI: 10.1371/journal.pgen.1000656] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 08/19/2009] [Indexed: 11/19/2022] Open
Abstract
Resection of DNA double-strand break (DSB) ends is generally considered a critical determinant in pathways of DSB repair and genome stability. Unlike for enzymatically induced site-specific DSBs, little is known about processing of random “dirty-ended” DSBs created by DNA damaging agents such as ionizing radiation. Here we present a novel system for monitoring early events in the repair of random DSBs, based on our finding that single-strand tails generated by resection at the ends of large molecules in budding yeast decreases mobility during pulsed field gel electrophoresis (PFGE). We utilized this “PFGE-shift” to follow the fate of both ends of linear molecules generated by a single random DSB in circular chromosomes. Within 10 min after γ-irradiation of G2/M arrested WT cells, there is a near-synchronous PFGE-shift of the linearized circular molecules, corresponding to resection of a few hundred bases. Resection at the radiation-induced DSBs continues so that by the time of significant repair of DSBs at 1 hr there is about 1–2 kb resection per DSB end. The PFGE-shift is comparable in WT and recombination-defective rad52 and rad51 strains but somewhat delayed in exo1 mutants. However, in rad50 and mre11 null mutants the initiation and generation of resected ends at radiation-induced DSB ends is greatly reduced in G2/M. Thus, the Rad50/Mre11/Xrs2 complex is responsible for rapid processing of most damaged ends into substrates that subsequently undergo recombinational repair. A similar requirement was found for RAD50 in asynchronously growing cells. Among the few molecules exhibiting shift in the rad50 mutant, the residual resection is consistent with resection at only one of the DSB ends. Surprisingly, within 1 hr after irradiation, double-length linear molecules are detected in the WT and rad50, but not in rad52, strains that are likely due to crossovers that are largely resection- and RAD50-independent. Double-strand breaks (DSBs) in chromosomal DNA are common sources of genomic change that may be beneficial or deleterious to an organism, from yeast to humans. While they can arise through programmed cellular events, DSBs are frequently associated with defective chromosomal replication, and they are induced by various types of DNA damaging agents such as those employed in cancer therapy, especially ionizing radiation. Elaborate systems have evolved for DSB recognition and subsequent repair, either by homologous recombination or by direct joining of ends. Although much is known about repair mechanisms associated with defined, artificially produced DSBs, there is a relative dearth of information about events surrounding random DSBs. Using a novel, yeast-based system that is applicable to other organisms, we have addressed resection at DSBs, considered a first step in repair. We provide the first direct evidence that cells possess a highly efficient system for recognition and initiation of resection at γ-radiation–induced dirty ends and that the resection is largely dependent on the Rad50/Mre11/Xrs2 complex, identified by the RAD50 gene. The system provides unique opportunities to address other components in resection and repair as well as to identify the contribution of random DSBs and resection to genome instability resulting from other DNA damaging agents.
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Affiliation(s)
- Jim Westmoreland
- Chromosome Stability Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Wenjian Ma
- Chromosome Stability Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Yan Yan
- Chromosome Stability Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Kelly Van Hulle
- Biology Department, Indiana University–Purdue University, Indianapolis, Indiana, United States of America
| | - Anna Malkova
- Biology Department, Indiana University–Purdue University, Indianapolis, Indiana, United States of America
| | - Michael A. Resnick
- Chromosome Stability Section, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
- * E-mail:
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22
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Borde V, Robine N, Lin W, Bonfils S, Géli V, Nicolas A. Histone H3 lysine 4 trimethylation marks meiotic recombination initiation sites. EMBO J 2008; 28:99-111. [PMID: 19078966 DOI: 10.1038/emboj.2008.257] [Citation(s) in RCA: 281] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 11/06/2008] [Indexed: 01/02/2023] Open
Abstract
The function of histone modifications in initiating and regulating the chromosomal events of the meiotic prophase remains poorly understood. In Saccharomyces cerevisiae, we examined the genome-wide localization of histone H3 lysine 4 trimethylation (H3K4me3) along meiosis and its relationship to gene expression and position of the programmed double-strand breaks (DSBs) that initiate interhomologue recombination, essential to yield viable haploid gametes. We find that the level of H3K4me3 is constitutively higher close to DSB sites, independently of local gene expression levels. Without Set1, the H3K4 methylase, 84% of the DSB sites exhibit a severely reduced DSB frequency, the reduction being quantitatively correlated with the local level of H3K4me3 in wild-type cells. Further, we show that this differential histone mark is already established in vegetative cells, being higher in DSB-prone regions than in regions with no or little DSB. Taken together, our results demonstrate that H3K4me3 is a prominent and preexisting mark of active meiotic recombination initiation sites. Novel perspectives to dissect the various layers of the controls of meiotic DSB formation are discussed.
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Affiliation(s)
- Valérie Borde
- Institut Curie Centre de Recherche, UMR7147 CNRS, Université Pierre et Marie Curie, Paris, France
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