Separation of DNA replication from the assembly of break-competent meiotic chromosomes
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PROVIDER: PRJNA152437 | ENA |
REPOSITORIES: ENA
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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: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:Faithful meiotic chromosome inheritance and fertility relies on the stimulation of meiotic crossover recombination by potentially genotoxic DNA double-strand breaks (DSBs). To avoid excessive damage, feedback mechanisms down-regulate DSBs on chromosomes that have successfully initiated crossover repair. In Saccharomyces cerevisiae, this regulation requires the removal of the conserved DSB-promoting protein Hop1/HORMAD during chromosome synapsis. Here, we identify privileged end-adjacent regions (EARs) spanning roughly 100 Kb near all telomeres that escape DSB downregulation. These regions retain Hop1 and continue to break in pachynema despite normal synaptonemal complex deposition. Differential retention of Hop1 requires the disassemblase Pch2/TRIP13, which preferentially removes Hop1 from telomere-distant sequences, and is modulated by the histone deacetylase Sir2 and the nucleoporin Nup2. Importantly, the uniform size of EARs among chromosomes contributes to disproportionately high DSB and repair signals on short chromosomes in pachynema, suggesting that EARs partially underlie the curiously high recombination rate of short chromosomes. Grant ID: Research grant #6-FY16-208 Grant title: Meiotic segregation of small chromosomes Funding Source: March of Dimes Foundation Affiliation: NEW YORK UNIVERSITY Name: Andreas Hochwagen
2019-01-10 | GSE105111 | 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 strictly 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.
| S-EPMC3355065 | biostudies-literature
Project description:Persistent DNA-break potential near telomeres increases initiation of meiotic recombination on short chromosomes
| PRJNA414664 | ENA
Project description:Crossover recombination is a hallmark of meiosis, which holds the paternal and maternal chromosomes (homologs) together for their faithful separation, meanwhile, it promotes genetic diversity of progenies. The pattern of crossover is mainly controlled by the architecture of meiotic chromosomes. Environmental factors, especially temperature, also play an important role in modulating crossovers. However, it is unclear how temperature affects crossovers. Here, we examined the distributions of budding yeast axis components (Red1, Hop1, and Rec8) and the CO-associated Zip3 foci in detail in different temperatures, and found that both increased and decreased temperatures result in shorter meiotic chromosome axes and more crossovers. Further investigations showed that altered temperature coordinately enhanced the hyperabundant accumulation of Hop1 and Red1 on chromosomes and the number of Zip3 foci. Most importantly, temperature-induced alterations in axis distribution and Zip3 foci depend on the changes in DNA negative supercoil. These findings suggest that yeast meiosis senses temperature changes by increasing the level of negative supercoil to increase crossovers and modulate chromosome organization. These findings provide a novel view in understanding the effect and mechanism of temperature on meiosis recombination and chromosome organization, and thus also have an important implication in evolution and breeding.
2024-07-30 | GSE246901 | GEO
Project description:Spo11-mediated DNA double strand breaks (DSBs) that initiate meiotic recombination are temporally and spatially controlled. The meiotic cohesin Rec8 has been implicated in regulating DSB formation, but little is known about the features of their interplay. To shed light on this point, we investigated the genome-wide localization of Spo11 in budding yeast during early meiosis by chromatin immunoprecipitation using high-density tiling arrays. We found that Spo11 is dynamically localized to meiotic chromosomes. Spo11 initially accumulated around centromeres and thereafter localized to arm regions as premeiotic S-phase proceeded. During this stage, a substantial proportion of Spo11 bound to Rec8 binding sites. Eventually, some of Spo11 further bound to both DSB and Rec8 sites. We also showed that such a change in a distribution of Spo11 is affected by hydroxyurea (HU) treatment. Interestingly, deletion of REC8 influences the localization of Spo11 to centromeres and in some of the intervals of the chromosomal arms. Thereby we observed a lack of DSB formation in a region-specific manner. These observations suggest that Rec8 would prearrange the distribution of Spo11 along chromosomes and will provide clues to understanding temporal and spatial regulation of DSB formation. Keywords: ChIP-chip â?¢ The goal of the experiment Genome-wide localization of Spo11, Mre11, Rec8, and DSB sites on meiotic chromosomes in Saccharomyces cerevisiae â?¢ Keywords Meiosis, Meiotic homologous recombination, Premeiotic DNA replication, cohesin, Saccharomyces cerevisiae, Genome tilling array (chromosome III, IV, V, VI), Spo11, Mre11, Rec8, DSB (Double strand break) â?¢ Experimental factor Distribution of Spo11, Mre11, and Rec8 in wild type in early meiosis (1.5 hrs, 2 hrs, 3 hrs, 4 hrs, and 5 hrs in sporulation medium) Distribution of Spo11 in rec8delta cells in early meiosis (1.5 hrs, 2 hrs, 3 hrs, 4 hrs, and 5 hrs in sporulation medium) Distribution of Spo11 in wild type in the presence of HU (2hrs and 4 hrs in sporulation medium containing HU) Distribution of DSB sites in rad50S mutant cells at 7 hrs in sporulation medium Distribution of DSB sites in rec8delta rad50S mutant cells at 7 hrs in sporulation medium â?¢ Experimental design ChIP analyses: SK1 background cells expressing FLAG tagged protein were used for the ChIP using anti-FLAG M2 antibody. ChIP-chip analyses: In all cases, hybridization data for ChIP fraction was compared with WCE (whole cell extract) fraction. Saccharomyces cerevisiae affymetrix genome tiling array (SC3456a520015F for chromosome III, IV, V, VI and rikDACF for chromosome VI) were used. Mapping of DSB sites: DSB rich fraction was concentrated by ChIP of Spo11-FLAG in rad50S mutant without crosslinking. In the mutant, DSBs ramain unrepaired with covalently attached Spo11.Meiotic cells (at 7 hours in sporulation medium) were used for the analyses. â?¢ Quality control steps taken Confirmation of several loci by quantitative real time PCR. Southern blotting of several DSB sites.
2010-05-18 | E-GEOD-8422 | biostudies-arrayexpress
Project description:Centromere Pairing Enables Correct Segregation of Meiotic Chromosomes
| PRJNA1069033 | ENA
Project description:Recombination-mediated linking of homologous chromosomes is a unique meiotic feature that enables the halving of chromosomal ploidy in sexual life cycles. Meiotic recombination is initiated by programmed DNA double-strand breaks (DSBs) that are generated by focal multi-protein clusters that condense onto chromosomal axes by poorly understood mechanisms. We discovered in mice that a DBF4-dependent kinase (DDK)–modulated interaction between IHO1 and the chromosomal axis component HORMAD1 effects the formation of axis-bound IHO1 platforms that enhance nucleation of cytologically distinguishable DSB-machinery clusters. This IHO1-HORMAD1-mediated seeding of the DSB-machinery ensures that sufficient DSBs form for efficient pairing of homologous chromosomes. In the absence of IHO1-HORMAD1 interaction, residual DSB activity depends on ANKRD31, which enhances both the seeding and the growth of DSB-machinery clusters. Thus, meiotic DSBs are ensured by complementing pathways that differentially effect seeding and growth of DSB-machinery clusters, and that synergistically enable assembly of the DSB machinery on chromosomal axes.
2024-02-23 | PXD042221 | Pride
Project description:Recombination-mediated linking of homologous chromosomes is a unique meiotic feature that enables the halving of chromosomal ploidy in sexual life cycles. Meiotic recombination is initiated by programmed DNA double-strand breaks (DSBs) that are generated by focal multi-protein clusters that condense onto chromosomal axes by poorly understood mechanisms. We discovered in mice that a DBF4-dependent kinase (DDK)–modulated interaction between IHO1 and the chromosomal axis component HORMAD1 effects the formation of axis-bound IHO1 platforms that enhance nucleation of cytologically distinguishable DSB-machinery clusters. This IHO1-HORMAD1-mediated seeding of the DSB-machinery ensures that sufficient DSBs form for efficient pairing of homologous chromosomes. In the absence of IHO1-HORMAD1 interaction, residual DSB activity depends on ANKRD31, which enhances both the seeding and the growth of DSB-machinery clusters. Thus, meiotic DSBs are ensured by complementing pathways that differentially effect seeding and growth of DSB-machinery clusters, and that synergistically enable assembly of the DSB machinery on chromosomal axes.
2024-02-23 | PXD042179 | Pride