Negative supcoils pattern meiotic crossovers
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE201366 | GEO | 2022/08/24
REPOSITORIES: GEO
Similar Datasets
Project description:Viable gamete formation requires segregation of homologous chromosomes connected, in most species, by crossovers. DNA double-strand break (DSB) formation and the resulting crossovers are regulated at multiple levels to prevent overabundance along chromosomes. Meiotic cells coordinate these events between distant sites, but the physical basis of long-distance chromosomal communication has been unknown. We show that DSB hotspots up to ~200 kb (~35 cM) apart form clusters via hotspot-binding proteins Rec25 and Rec27 in fission yeast. Clustering coincides with hotspot competition and interference over similar distances. Without Tel1 (ATM tumor-suppressor homolog), DSB and crossover interference become negative, reflecting coordinated action along a chromosome. These results indicate that DSB hotspots within a limited chromosomal region and bound by their protein determinants form a clustered structure that, via Tel1, allows only one DSB per region. Such a “roulette” process among clusters explains the observed pattern of crossover interference in fission yeast. Key structural and regulatory components of clusters are phylogenetically conserved, suggesting conservation of this vital regulation. Based on these observations, we discuss variations on a model in which clustering and competition between DSB sites leads to DSB interference and in turn produces crossover interference.
2018-09-17 | GSE119920 | GEO
Project description:Viable gamete formation requires segregation of homologous chromosomes connected, in most species, by crossovers. DNA double-strand break (DSB) formation and the resulting crossovers are regulated at multiple levels to prevent overabundance along chromosomes. Meiotic cells coordinate these events between distant sites, but the physical basis of long-distance chromosomal communication has been unknown. We show that DSB hotspots up to ~200 kb (~35 cM) apart form clusters via hotspot-binding proteins Rec25 and Rec27 in fission yeast. Clustering coincides with hotspot competition and interference over similar distances. Without Tel1 (ATM tumor-suppressor homolog), DSB and crossover interference become negative, reflecting coordinated action along a chromosome. These results indicate that DSB hotspots within a limited chromosomal region and bound by their protein determinants form a clustered structure that, via Tel1, allows only one DSB per region. Such a “roulette” process among clusters explains the observed pattern of crossover interference in fission yeast. Key structural and regulatory components of clusters are phylogenetically conserved, suggesting conservation of this vital regulation. Based on these observations, we discuss variations on a model in which clustering and competition between DSB sites leads to DSB interference and in turn produces crossover interference.
2018-09-17 | GSE119745 | GEO
Project description:The data set submitted here contains the raw SNP genotyping data obtained from the analysis of 24 biparental segregating maize (Zea mays L.) populations and their respective parents. The processed and filtered data were used to construct genetic linkage maps which we used in our study of variation of recombination rate in maize. In sexually reproducing organisms, meiotic crossovers ensure the proper segregation of chromosomes and contribute to genetic diversity by shuffling allelic combinations. Such genetic reassortment is exploited in breeding to combine favorable alleles, and in genetic research to identify genetic factors underlying traits of interest via linkage or association-based approaches. Crossover numbers and distributions along chromosomes vary between species, but little is known about their intraspecies variation. In our study, we report on the variation of recombination rates between 22 European maize inbred lines that belong to the Dent and Flint gene pools. We genotyped 23 doubled-haploid populations derived from crosses between these lines with a 50k-SNP array and constructed high-density genetic maps, showing good correspondence with the maize B73 genome sequence assembly. By aligning each genetic map to the B73 sequence, we obtained the recombination rates along chromosomes specific to each population. We identified significant differences in recombination rates at the genome-wide, chromosome, and intrachromosomal levels between populations, as well as significant variation for genome-wide recombination rates among maize lines. Crossover interference analysis using a two-pathway modeling framework revealed a negative association between recombination rate and interference strength. To our knowledge, the present work provides the most comprehensive study on intraspecific variation of recombination rates and crossover interference strength in eukaryotes. Differences found in recombination rates will allow for selection of high or low recombining lines in crossing programs. Our methodology should pave the way for precise identification of genes controlling recombination rates in maize and other organisms.
2013-09-05 | GSE50558 | GEO
Project description:In meiosis, an excess number of DNA double-strand breaks (DSBs), the initiating DNA lesion, is formed compared to the number of crossovers, one of their repair products that creates the physical links between homologs and allows their correct segregation. It is not known if all DSB hotspots are also crossover hotspots, or if the ratio between DSB and crossovers varies with the chromosomal location. Here, to systematically investigate variation in the DSB/crossover ratio, we have established the genome-wide map of the Zip3 protein binding sites in budding yeast meiosis. We show that Zip3 associates with DSB sites when these are engaged into repair by crossing over, and that Zip3 binding frequency at DSB reflects its tendency to be repaired as a crossover. We further show that the relative amount of Zip3 per DSB varies with the chromosomal location and identify chromosomal features associated with high or low Zip3 per DSB ratio. Among these is the negative regulation by proximity to a centromere and positive by the proximity to axis-associated sequences. This work opens interesting perspectives to understand the role of these extra DSB that are not frequently used for crossover and our findings may extend to mammals that have a large excess of DSB compared to crossovers. ChIP-chip experiment in meiotic diploid SK1 yeast cells - two biological replicates
2013-12-18 | E-GEOD-40563 | biostudies-arrayexpress
Project description:During meiosis, crossover recombination is essential to link homologous chromosomes and drive faithful chromosome segregation. Crossover recombination is non-random across the genome, and centromere-proximal crossovers are associated with an increased risk of aneuploidy, including Trisomy 21 in humans. Here, we identify the conserved Ctf19/CCAN kinetochore sub-complex as a major factor that minimizes potentially deleterious centromere-proximal crossovers in budding yeast. We uncover multi-layered suppression of pericentromeric recombination by the Ctf19 complex, operating across distinct chromosomal distances. The Ctf19 complex prevents meiotic DNA break formation, the initiating event of recombination, proximal to the centromere. The Ctf19 complex independently drives the enrichment of cohesin throughout the broader pericentromere to suppress crossovers, but not DNA breaks. This non-canonical role of the kinetochore in defining a chromosome domain that is refractory to crossovers adds a new layer of functionality by which the kinetochore prevents the incidence of chromosome segregation errors that generate aneuploid gametes.
2015-12-15 | GSE72683 | GEO
Project description:During meiotic prophase, concurrent transcription, recombination, and chromosome synapsis place substantial topological strain on chromosomal DNA, but the role of topoisomerases in this context remains poorly defined. Here, we analyzed the roles topoisomerases I and II (Top1 and Top2) during meiotic prophase in Saccharomyces cerevisiae. We show that both topoisomerases accumulate primarily in promoter-containing intergenic regions of actively transcribing genes, including many meiotic double-strand break (DSB) hotspots. Despite the comparable binding patterns, top1 and top2 mutations have different effects on meiotic recombination. TOP1 disruption delays DSB induction and shortens the window of DSB accumulation by an unknown mechanism. By contrast, temperature-sensitive top2-1 mutants exhibit a marked delay in meiotic chromosome remodeling and elevated DSB signals on synapsed chromosomes. The problems in chromosome remodeling were linked to altered Top2 binding patterns rather than a loss of Top2 catalytic activity and stemmed from a defect in recruiting the chromosome remodeler Pch2/TRIP13 to synapsed chromosomes. No chromosomal defects were observed in the absence of TOP1. Our results imply independent roles for topoisomerases I and II in modulating meiotic chromosome structure and recombination.
2020-03-06 | GSE131994 | GEO
Project description:Every chromosome requires at least one crossover to be faithfully segregated during meiosis. At least two levels of regulation govern crossover distribution; where the initiating DNA double-strand breaks (DSBs) occur and whether those DSBs are repaired as crossovers. We mapped meiotic DSBs in budding yeast by identifying sites of DSB-associated single-stranded DNA (ssDNA) accumulation. These analyses revealed substantial DSB activity in regions close to centromeres, where crossover formation is largely absent. Our data suggest that centromeric suppression of recombination occurs at the level of break repair rather than DSB formation. Additionally, we found an enrichment of DSBs within a ~100-kb region near the ends of all chromosomes. Introduction of new telomeres was sufficient to induce large ectopic regions of increased DSB formation, revealing a remarkable long-range effect of telomeres on DSB formation. The concentration of DSBs close to chromosome ends increases the relative DSB density on small chromosomes, providing an interference-independent mechanism to ensure that all chromosomes receive at least one crossover per homolog pair. Together, our results indicate that selective DSB repair accounts for crossover suppression near centromeres, and suggest a simple telomere-guided mechanism to ensure sufficient DSB activity on all chromosomes. Keywords: ssDNA analysis, comparative genomic hybridization, ChIP-chip
2007-11-15 | GSE9503 | GEO
Project description:During meiosis, crossover recombination is essential to link homologous chromosomes and drive faithful chromosome segregation. Crossover recombination is non-random across the genome, and centromere-proximal crossovers are associated with an increased risk of aneuploidy, including Trisomy 21 in humans. Here, we identify the conserved Ctf19/CCAN kinetochore sub-complex as a major factor that minimizes potentially deleterious centromere-proximal crossovers in budding yeast. We uncover multi-layered suppression of pericentromeric recombination by the Ctf19 complex, operating across distinct chromosomal distances. The Ctf19 complex prevents meiotic DNA break formation, the initiating event of recombination, proximal to the centromere. The Ctf19 complex independently drives the enrichment of cohesin throughout the broader pericentromere to suppress crossovers, but not DNA breaks. This non-canonical role of the kinetochore in defining a chromosome domain that is refractory to crossovers adds a new layer of functionality by which the kinetochore prevents the incidence of chromosome segregation errors that generate aneuploid gametes. Two samples total: two biological replicate Spo11-oligo maps of S. cerevisiae SK1 mcm21 null mutant
2015-12-15 | E-GEOD-72683 | biostudies-arrayexpress
Project description:The data set submitted here contains the raw SNP genotyping data obtained from the analysis of 24 biparental segregating maize (Zea mays L.) populations and their respective parents. The processed and filtered data were used to construct genetic linkage maps which we used in our study of variation of recombination rate in maize. In sexually reproducing organisms, meiotic crossovers ensure the proper segregation of chromosomes and contribute to genetic diversity by shuffling allelic combinations. Such genetic reassortment is exploited in breeding to combine favorable alleles, and in genetic research to identify genetic factors underlying traits of interest via linkage or association-based approaches. Crossover numbers and distributions along chromosomes vary between species, but little is known about their intraspecies variation. In our study, we report on the variation of recombination rates between 22 European maize inbred lines that belong to the Dent and Flint gene pools. We genotyped 23 doubled-haploid populations derived from crosses between these lines with a 50k-SNP array and constructed high-density genetic maps, showing good correspondence with the maize B73 genome sequence assembly. By aligning each genetic map to the B73 sequence, we obtained the recombination rates along chromosomes specific to each population. We identified significant differences in recombination rates at the genome-wide, chromosome, and intrachromosomal levels between populations, as well as significant variation for genome-wide recombination rates among maize lines. Crossover interference analysis using a two-pathway modeling framework revealed a negative association between recombination rate and interference strength. To our knowledge, the present work provides the most comprehensive study on intraspecific variation of recombination rates and crossover interference strength in eukaryotes. Differences found in recombination rates will allow for selection of high or low recombining lines in crossing programs. Our methodology should pave the way for precise identification of genes controlling recombination rates in maize and other organisms. Related publication: Bauer E, Falque M, Walter H, Bauland C, Camisan C, Campo L, Meyer N, Ranc N, Rincent R, Schipprack W, Altmann T, Flament P, Melchinger AE, Menz M, Moreno-González J, Ouzunova M, Revilla P, Charcosset A, Martin OC, Schön C-C (2013) Intraspecific variation of recombination rate in maize. Genome Biology (submitted) We genotyped 2233 maize DH lines from 24 biparental populations, and the 23 parents of these populations using the Illumina MaizeSNP50 BeadChip. We created two large half-sib panels, one each for the Dent and the Flint germplasm. The Dent populations have the prefix CFD, the Flint populations have the prefix CFF. In each panel, a common central parent was crossed to diverse founder lines, and doubled haploids were generated from the respective F1 plants. For a detailed description of the material, see Bauer et al. (2013) Genome Biology (submitted). We submit here three datasets: 1) Dataset Parents comprises all 23 parental lines. 2) Dataset CFD comprises all 1005 DH lines from Dent crosses, 3) Dataset CFF comprises all 1262 DH lines from Flint crosses.
2013-09-05 | E-GEOD-50558 | biostudies-arrayexpress
Project description:Meiotic crossover formation requires the stabilization of early recombination intermediates by a set of proteins and occurs within the environment of the chromosome axis, a structure important for the regulation of meiotic recombination events. The molecular mechanisms underlying and connecting crossover recombination and axis localization are elusive. Here, we identified the ZZS (Zip2–Zip4–Spo16) complex, required for crossover formation, which carries two distinct activities: one provided by Zip4, which acts as hub through physical interactions with components of the chromosome axis and the crossover machinery, and the other carried by Zip2 and Spo16, which preferentially bind branched DNA molecules in vitro. We found that Zip2 and Spo16 share structural similarities to the structure-specific XPF–ERCC1 nuclease, although it lacks endonuclease activity. The XPF domain of Zip2 is required for crossover formation, suggesting that, together with Spo16, it has a noncatalytic DNA recognition function. Our results suggest that the ZZS complex shepherds recombination intermediates toward crossovers as a dynamic structural module that connects recombination events to the chromosome axis. The identification of the ZZS complex improves our understanding of the various activities required for crossover implementation and is likely applicable to other organisms, including mammals.
2018-02-14 | GSE103877 | GEO