Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA174310 | ENA |
REPOSITORIES: ENA
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Project description:Histone H3K4 methylation is a feature of meiotic recombination hotspots shared by many organisms including plants and mammals. Meiotic recombination is initiated by programmed double strand break (DSB) formation that in budding yeast is directed in gene promoters by histone H3K4 di/trimethylation. This histone modification is indeed recognized by Spp1, a PHD-finger containing protein that belongs to the conserved histone H3K4 methyltransferase Set1 complex. During meiosis, Spp1 binds H3K4me and recruits a DSB protein, Mer2, to promote DSB formation close to gene promoters. How Set1C and Mer2 related functions of Spp1 are connected is not clear.
2018-01-30 | PXD007590 | Pride
Project description:PRDM9 specifies the sites of meiotic DNA double strand break that initiate meiotic recombination in mice and humans. PRDM9 is known to bind to specific DNA sequences with its DNA binding domain, to induce H3K4me3 and H3K36me3 to adjacent nucleosomes through its methyltransferase activity, and to recruit or activate the meiotic DSB machinery. To understand how PRDM9 executes these various steps, we set up to identify its partners. This was performed by a proteomic approach where protein extracts from mouse testis were immunoprecipitated with anti-PRDM9 antibody for mass spectrometry analysis.
2020-12-03 | PXD017337 | Pride
Project description:Crossovers formed by recombination between homologous chromosomes are important for proper homolog segregation during meiosis and for generation of genetic diversity. Optimal molecular analysis of DNA intermediates of recombination requires synchronous cultures. We previously described a mutant, pat1-as2, of the fission yeast Schizosaccharomyces pombe that undergoes synchronous meiosis at 25°C when an ATP analog is added to the culture. Here, we compare recombination intermediates in pat1-as2 at 25°C with those in the widely used pat1-114 temperature-sensitive mutant at 34°C, a temperature higher than optimal. DNA double-strand breaks at most hotspots are similarly abundant in the two conditions but, remarkably, a few hotspots are distinctly deficient at 25°C. In both conditions Holliday junctions at DNA break hotspots form more frequently between sister chromatids than between homologs, but a novel species, perhaps arising from invasion by only one end of broken DNA, is more readily observed at 25°C. Our results confirm the validity of previous assays of recombination intermediates in S. pombe and provide new information on the mechanism of meiotic recombination. DNA double-strand break analysis by immunoprecipation of Rec12-FLAG covalently linked to DNA (without exogenous crosslinking agent used) following meiotic induction via pat1-114 or pat1-as2 alleles
2013-09-20 | E-GEOD-49961 | biostudies-arrayexpress
Project description:Meiotic recombination in mammals requires recombination hotspot activation through the action of the histone 3 lysine-4 and lysine-36 methyltransferase PRDM9 to ensure successful double-strand break initiation and repair. Here using a Ewsr1 male germ cell conditional knockout mouse, we show that EWSR1 increases the efficiency of PRDM9-dependent H3K4/K36 trimethylation at the adjacent nucleosomes in vivo, and directs the hotspot choices for double-strand breaks formation and their subsequent repair into sufficient number of crossovers properly positioned along the centromere-telomere axis.
2020-12-17 | GSE108259 | GEO
Project description:HELB is a human helicase involved in initiation of DNA replication, the replication stress response, and regulation of double-strand DNA break repair. rs75770066 is a low-frequency single-nucleotide polymorphism (SNP) in the HELB gene that affects age at natural menopause. rs75770066 results in a D506G substitution in a HELB specific insertion in the 1A domain of the helicase that contains amino acids known to interact with RPA. We found that this amino acid change has no effect on the enzymatic activity of HELB but dramatically impairs the cellular function of HELB. D506G HELB exhibits impaired interaction with RPA, which likely results in the effects of rs75770066 as this reduces recruitment of HELB to sites of DNA damage. Reduced recruitment of D506G-HELB to double-strand DNA breaks and the concomitant increase in homologous recombination likely alters the levels of meiotic recombination, which affects the viability of gametes. Because menopause occurs when oocyte levels drop below a minimum threshold, altered repair of meiotic double-stranded DNA breaks has the potential to directly affect the age at natural menopause.
2024-11-12 | MSV000096390 | MassIVE
Project description:Meiotic recombination ensures proper chromosome segregation to form viable gametes and results in gene conversion events between homologs. Conversion tracts are shorter in meiosis than in mitotically dividing cells. This results at least in part from the binding of a complex, formed of the Mer3 helicase and the MutL heterodimer, to meiotic recombination intermediates. The molecular actors inhibited by this complex are elusive. The Pif1 DNA helicase is known to stimulate DNA polymerase delta (Pol δ) -mediated DNA synthesis from D-loops in vitro, allowing long synthesis required for break-induced replication. We show that Pif1 is recruited genome wide to meiotic double-strand break (DSB) sites. We further show that Pif1, through its interaction with PCNA, is required for the long gene conversions observed in the absence of MutL recruitment to recombination sites. in vivo, Mer3 interacts with the PCNA clamp loader RFC, and in vitro, Mer3-MutL ensemble inhibits Pif1-stimulated D-loop extension by Pol δ and RFC-PCNA. Mechanistically, our results suggest that Mer3-MutL may compete with Pif1 for binding to RFC-PCNA. Taken together, our data show that Pif1’s activity to promote meiotic recombination-related DNA synthesis is restrained by the Mer3-MutL ensemble to prevent long gene conversion events and possibly associated mutagenesis.
2021-03-01 | GSE164467 | GEO
Project description:In most eukaryotes, meiotic crossovers are essential for error-free chromosome segregation but are specifically repressed near centromeres to prevent missegregation. Recognized for >85 years, the molecular mechanism of this repression has remained unknown. Meiotic chromosomes contain two distinct cohesin complexes: pericentric complex (for segregation) and chromosomal arm complex (for crossing-over). We show that the pericentric-specific complex also actively represses pericentric meiotic double-strand break (DSB) formation and, consequently, crossovers. The fission yeast pericentric regions contain heterochromatin, removal of which can result in derepression in double-strand break formation and recombination during meiosis. We uncover the mechanism by which fission yeast heterochromatin protein Swi6 (mammalian HP1-homolog) prevents recruitment of activators of meiotic DSB formation such as Rec10. Localizing these missing activators to wild-type pericentromeres bypasses repression and generates abundant crossovers but reduces gamete viability.The molecular mechanism elucidated here likely extends to other species including humans, where pericentric crossovers can result in disorders such as Down syndrome. These mechanistic insights provide new clues to understand the roles played by multiple cohesin complexes, especially in human infertility and birth defects.
2018-06-14 | GSE115726 | GEO
Project description:DNA double-strand breaks (DSBs) initiate meiotic recombination. Past DSB-mapping studies have used rad50S or sae2? mutants, which are defective in break processing, to accumulate DSBs, and report large (= 50 kb) “DSB-hot” regions that are separated by “DSB-cold” domains of similar size. Substantial recombination occurs in some DSB-cold regions, suggesting that DSB patterns are not normal in rad50S or sae2? mutants. We therefore developed novel methods that detect DSBs using ssDNA enrichment and microarray hybridization, and that use background-based normalization to allow cross-comparison between array datasets, to map genome-wide the DSBs that accumulate in processing-capable, repair-defective dmc1î and dmc1î rad51î mutants. DSBs were observed at known hotspots, but also in most previously-identified “DSB-cold” regions, including near centromeres and telomeres. While about 40% of the genome is DSB-cold in rad50S mutants, analysis of meiotic ssDNA from dmc1? shows that most of these regions have significant DSB activity. Thus, DSBs are distributed much more uniformly than was previously believed. Southern-blot assays of DSBs in selected regions in dmc1?, rad50S and wild-type cells confirm these findings. Comparisons of DSB signals in dmc1, dmc1 rad51, and dmc1 spo11 mutant strains identify Dmc1 as the primary strand transfer activity genome-wide, and Spo11-induced lesions as initiating all meiotic recombination. Keywords: DSB mapping, ChIP-chip, single strand DNA , BND cellulose We use two different strategies to map the genome-wide distribution of meiotic DSBs in the yeast Saccharomyces cerevisiae. The first is a chromatin immunoprecipitation (ChIP) based approach that targets the Spo11p protein, which remains covalently attached to DSB ends in the rad50S mutant background. The second approach involves BND cellulose enrichment of the single strand DNA (ssDNA) recombination intermediate formed by end-resection at DSB sites following Spo11p removal. We use dmc1 and dmc1 rad51 mutants that accumulates meiotic single strand DNA intermediates
2007-12-30 | E-GEOD-8981 | biostudies-arrayexpress
Project description:During meiotic prophase I, germ cells must balance transcriptional activation with meiotic recombination and chromosome synapsis, biological processes requiring extensive changes to chromatin state and structure. Here we explored the interplay between chromatin accessibility and transcription across a detailed time-course of murine male meiosis by measuring genome-wide patterns of chromatin accessibility, transcription, and processed mRNA. To understand the relationship between these parameters of gene regulation and recombination, we integrated these data with maps of double-strand break formation. Maps of nascent transcription showed that Pol II is loaded on chromatin and maintained in a paused state early during meiosis. In pachynema, paused Pol II is released in a coordinated transcriptional burst resulting in ~3-fold increase in transcription. Release from pause is mediated by the transcription factor A-MYB and the testis-specific bromodomain protein, BRDT. The burst of transcriptional activity is both temporally and spatially segregated from key steps of meiotic recombination: double strand breaks show evidence of chromatin accessibility earlier during prophase I and at distinct loci from those undergoing transcriptional activation, despite shared chromatin marks. Our findings uncover the mechanisms of transcriptional activation and how cells compartmentalize transcription and recombination during meiosis.
2022-09-30 | GSE212116 | GEO
Project description:During meiotic prophase I, germ cells must balance transcriptional activation with meiotic recombination and chromosome synapsis, biological processes requiring extensive changes to chromatin state and structure. Here we explored the interplay between chromatin accessibility and transcription across a detailed time-course of murine male meiosis by measuring genome-wide patterns of chromatin accessibility, transcription, and processed mRNA. To understand the relationship between these parameters of gene regulation and recombination, we integrated these data with maps of double-strand break formation. Maps of nascent transcription showed that Pol II is loaded on chromatin and maintained in a paused state early during meiosis. In pachynema, paused Pol II is released in a coordinated transcriptional burst resulting in ~3-fold increase in transcription. Release from pause is mediated by the transcription factor A-MYB and the testis-specific bromodomain protein, BRDT. The burst of transcriptional activity is both temporally and spatially segregated from key steps of meiotic recombination: double strand breaks show evidence of chromatin accessibility earlier during prophase I and at distinct loci from those undergoing transcriptional activation, despite shared chromatin marks. Our findings uncover the mechanisms of transcriptional activation and how cells compartmentalize transcription and recombination during meiosis.
2022-09-30 | GSE212118 | GEO