Ontology highlight
ABSTRACT:
PROVIDER: PRJNA233964 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Genetic recombination generates novel trait combinations, and understanding how recombination is distributed across the genome is key to modern genetics. The PRDM9 protein defines recombination hotspots; however, megabase-scale recombination patterning is independent of PRDM9. The single round of DNA replication, which precedes recombination in meiosis, may establish these patterns; therefore, we devised an approach to study meiotic replication that includes robust and sensitive mapping of replication origins. We find that meiotic DNA replication is distinct; reduced origin firing slows replication in meiosis, and a distinctive replication pattern in human males underlies the subtelomeric increase in recombination. We detected a robust correlation between replication and both contemporary and historical recombination and found that replication origin density coupled with chromosome size determines the recombination potential of individual chromosomes. Our findings and methods have implications for understanding the mechanisms underlying DNA replication, genetic recombination, and the landscape of mammalian germline variation.
2021-07-02 | GSE148327 | GEO
Project description:The meiotic cell division reduces the chromosome number from diploid to haploid to form gametes for sexual reproduction. Although much progress has been made in understanding meiotic recombination and the two meiotic divisions, the processes leading up to recombination, including the prolonged pre-meiotic S phase (meiS) and the assembly of meiotic chromosome axes, remain poorly defined. We have used genome-wide approaches in Saccharomyces cerevisiae to measure the kinetics of pre-meiotic DNA replication, and to investigate the interdependencies between replication and axis formation. We found that replication initiation was delayed for a large number of origins in meiS compared to mitosis, and that meiotic cells were far more sensitive to replication inhibition, most likely due to the starvation conditions required for meiotic induction. Moreover, replication initiation was delayed even in the absence of chromosome axes, indicating replication timing is independent of the process of axis assembly. Finally, we found that cells were able to install axis components and initiate recombination on unreplicated DNA. Thus, although pre-meiotic DNA replication and meiotic chromosome axis formation occur concurrently, they are not directly coupled. The functional separation of these processes reveals a modular method of building meiotic chromosomes, and predicts that any crosstalk between these modules must occur through superimposed regulatory mechanisms. This SuperSeries is composed of the SubSeries listed below.
2012-06-15 | GSE35667 | GEO
Project description:Eukaryotic DNA replication is regulated by conserved mechanisms that bring about a spatial and temporal organization in which distinct genomic domains are copied at characteristic times during S phase. Although this replication program has been closely linked with genome architecture, we still do not understand key aspects of how chromosomal context modulates the activity of replication origins. To address this question, we have exploited models that combine engineered genomic rearrangements with the unique replication programs of post-quiescence and pre-meiotic S phases. Our results demonstrate that large-scale inversions surprisingly do not affect cell proliferation and meiotic progression, despite inducing a restructuring of replication domains on each rearranged chromosome. Remarkably, these alterations in the organization of DNA replication are entirely due to changes in the positions of existing origins along the chromosome, as their efficiencies remain virtually unaffected genome wide. However, we identified striking alterations in origin firing proximal to the fusion points of each inversion, suggesting that the immediate chromosomal neighborhood of an origin is a crucial determinant of its activity. Interestingly, the impact of genome reorganization on replication initiation is highly comparable in the post-quiescent and pre-meiotic S phases, despite the differences in DNA metabolism in these two physiological states. Our findings therefore shed new light on how origin selection and the replication program are governed by chromosomal architecture. Genes 2022, 13(7), 1244; https://doi.org/10.3390/genes13071244
2022-08-12 | GSE210821 | GEO
Project description:The meiotic cell division reduces the chromosome number from diploid to haploid to form gametes for sexual reproduction. Although much progress has been made in understanding meiotic recombination and the two meiotic divisions, the processes leading up to recombination, including the prolonged pre-meiotic S phase (meiS) and the assembly of meiotic chromosome axes, remain poorly defined. We have used genome-wide approaches in Saccharomyces cerevisiae to measure the kinetics of pre-meiotic DNA replication, and to investigate the interdependencies between replication and axis formation. We found that replication initiation was delayed for a large number of origins in meiS compared to mitosis, and that meiotic cells were far more sensitive to replication inhibition, most likely due to the starvation conditions required for meiotic induction. Moreover, replication initiation was delayed even in the absence of chromosome axes, indicating replication timing is independent of the process of axis assembly. Finally, we found that cells were able to install axis components and initiate recombination on unreplicated DNA. Thus, although pre-meiotic DNA replication and meiotic chromosome axis formation occur concurrently, they are not directly coupled. The functional separation of these processes reveals a modular method of building meiotic chromosomes, and predicts that any crosstalk between these modules must occur through superimposed regulatory mechanisms. Multiple studies of meiotic chromosomes were undertaken. To study DNA replication, the locations of replicative helicase (Mcm2-7) were mapped in pre-meiotic and pre-mitotic cells, and DNA replication profiles were created for pre-meiotic S (meiS) and pre-mitotic S (mitS) phases. Early origins were mapped in hydroxyurea for wild-type cells in mitS + 200mM HU, and meiS +20mM HU for wild-type, sml1, rec8 and spo11 deletion cells. Rec8, Hop1 and Red1 binding to meiotic chromosomes was evaluated using ChIP-chip in wild-type cells with and without 20 mM HU, and in cdc6-mn and clb5 clb6 delete cells. Finally, meiotic DNA double-strand breaks (DSBs) were mapped in cdc6-mn dmc1 delete cells by measuring the ssDNA that accumulates at DSB hotspots. This SuperSeries is composed of the following subset Series: GSE35658: Chromatin IP for Mcm2-7, Rec8, Hop1 and Red1 GSE35662: S phase and HU profiles in wild-type and mutant cells GSE35666: DSB formation in replication compromised cells
2012-06-14 | E-GEOD-35667 | biostudies-arrayexpress
Project description:Meiotic recombination is initiated by the Spo11-dependent programmed DNA double-strand breaks (DSBs) that are preferentially concentrated within genomic regions known as hotspots, but the factor(s) which specify the positions for meiotic DSB hotspots remain unclear. Here, we show that the frequency and distribution of R-loops, a type of functional chromatin structure comprising single-stranded DNA and a DNA:RNA hybrid, change dramatically throughout meiosis. We detected the formation of multiple de novo R-loops in the pachytene stage, and found they co-localize with meiotic DSB hotspots. We further show that transcription-replication head-on collisions could promote R-loop formation during meiosis, and apparently direct the initiation of meiotic DSB formation. Furthermore, the hotspots can be eliminated by reverse the direction of either transcription or replication, and reconstituted by reverse both of their direction. Our study reveals that R-loops may play dual roles in meiotic recombination. In addition to participation in meiotic DSB processing, some meiotic DSB hotspots may be originated from the transcription-replication head-on collisions during meiotic DNA replication.
2023-05-14 | GSE167915 | GEO
Project description:During gamete formation, crossover recombination must occur on replicated DNA to ensure proper chromosome segregation in the first meiotic division. We identified a Mec1/ATR-dependent replication checkpoint in budding yeast that prevented the earliest stage of recombination, the programmed induction of DNA double-strand breaks (DSBs), when pre-meiotic DNA replication was delayed. The checkpoint suppressed DSBs through three complementary mechanisms: inhibition of Mer2 phosphorylation by Dbf4-dependent Cdc7 kinase, preclusion of chromosomal loading of Rec114 and Mre11, and lowered abundance of the Spo11 nuclease. Without this checkpoint, cells formed DSBs on partially replicated chromosomes. Importantly, such DSBs frequently failed to be repaired and impeded further DNA synthesis, leading to a rapid loss in cell viability. We conclude that a checkpoint-dependent constraint of DSB formation to duplicated DNA is critical not only for meiotic chromosome assortment, but also to protect genome integrity during gametogenesis.
2013-09-20 | GSE46841 | GEO
Project description:During gamete formation, crossover recombination must occur on replicated DNA to ensure proper chromosome segregation in the first meiotic division. We identified a Mec1/ATR-dependent replication checkpoint in budding yeast that prevented the earliest stage of recombination, the programmed induction of DNA double-strand breaks (DSBs), when pre-meiotic DNA replication was delayed. The checkpoint suppressed DSBs through three complementary mechanisms: inhibition of Mer2 phosphorylation by Dbf4-dependent Cdc7 kinase, preclusion of chromosomal loading of Rec114 and Mre11, and lowered abundance of the Spo11 nuclease. Without this checkpoint, cells formed DSBs on partially replicated chromosomes. Importantly, such DSBs frequently failed to be repaired and impeded further DNA synthesis, leading to a rapid loss in cell viability. We conclude that a checkpoint-dependent constraint of DSB formation to duplicated DNA is critical not only for meiotic chromosome assortment, but also to protect genome integrity during gametogenesis. DSB factor association was measured in wild-type and checkpoint mutants strains under non-inducing or replication checkpoint inducing conditions. Additionally, DNA replication and helicase loading were measured in a replication and checkpoint deficient strain (cdc6-mn).
2013-09-20 | E-GEOD-46841 | biostudies-arrayexpress
Project description:To segregate accurately during meiosis, homologous chromosomes in most species must recombine. Very small chromosomes would risk missegregation if recombination were randomly distributed, so the double-strand breaks (DSBs) that initiate recombination are not haphazard. How this nonrandomness is controlled is not understood. Here we demonstrate that Saccharomyces cerevisiae integrates multiple, temporally distinct pathways to regulate chromosomal binding of pro-DSB factors Rec114 and Mer2, thereby controlling duration of a DSB-competent state. Homologous chromosome engagement regulates Rec114/Mer2 dissociation late in prophase, whereas replication timing and proximity to centromeres or telomeres influence timing and amount of Rec114/Mer2 accumulation early. A distinct early mechanism boosts Rec114/Mer2 binding quickly to high levels specifically on the shortest chromosomes, dependent on chromosome axis proteins and subject to selection pressure to maintain hyperrecombinogenic properties of these chromosomes. Thus, an organism’s karyotype and its attendant risk of meiotic missegregation influence the shape and evolution of its recombination landscape.
2018-09-12 | GSE119787 | GEO
Project description:To segregate accurately during meiosis, homologous chromosomes in most species must recombine. Very small chromosomes would risk missegregation if recombination were randomly distributed, so the double-strand breaks (DSBs) that initiate recombination are not haphazard. How this nonrandomness is controlled is not understood. Here we demonstrate that Saccharomyces cerevisiae integrates multiple, temporally distinct pathways to regulate chromosomal binding of pro-DSB factors Rec114 and Mer2, thereby controlling duration of a DSB-competent state. Homologous chromosome engagement regulates Rec114/Mer2 dissociation late in prophase, whereas replication timing and proximity to centromeres or telomeres influence timing and amount of Rec114/Mer2 accumulation early. A distinct early mechanism boosts Rec114/Mer2 binding quickly to high levels specifically on the shortest chromosomes, dependent on chromosome axis proteins and subject to selection pressure to maintain hyperrecombinogenic properties of these chromosomes. Thus, an organism’s karyotype and its attendant risk of meiotic missegregation influence the shape and evolution of its recombination landscape.
2018-09-12 | GSE119786 | GEO
Project description:Higher-order chromosome structure is assumed to control various DNA-templated reactions in eukaryotes. Meiotic chromosomes implement developed structures called “axes” and “loops”; both are suggested to tether each other, activating Spo11 to catalyze meiotic DNA double-strand breaks (DSBs) at recombination hotspots. We found that the Schizosaccharomyces pombe Spo11 homolog Rec12 and its partners form two distinct subcomplexes, DSBC (Rec6-Rec12-Rec14) and SFT (Rec7-Rec15-Rec24). Additionally, Mde2, whose expression is strictly regulated by the replication checkpoint, interacts with a component of each subcomplex. The SFT subcomplex binds to both axes via direct interaction of Rec15 with Rec10 in axes and DSB sites, hence axial Rec10 can partially tether DSB sites located in loops. Importantly, this multiprotein-based tethered axis-loop complex is destabilized in the absence of Mde2. We therefore propose a novel mechanism by which Mde2 functions as a recombination initiation mediator to tether axes and loops, in liaison with the meiotic replication checkpoint.
2012-07-28 | GSE31846 | GEO