Principles of chromosome organization for meiotic recombination
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ABSTRACT:
PROVIDER: PRJNA1091364 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR28432900_1.fastq.gz | Fastqsanger.gz | |||
| SRR28432900_2.fastq.gz | Fastqsanger.gz | |||
| SRR28432901_1.fastq.gz | Fastqsanger.gz | |||
| SRR28432901_2.fastq.gz | Fastqsanger.gz | |||
| SRR28432902_1.fastq.gz | Fastqsanger.gz |
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Project description:In meiotic cells, chromosomes are organized as chromatin loop arrays anchored to a protein axis. This organization is essential to regulate meiotic recombination, from DNA double-strand break (DSB) formation to their repair. In mammals, it is unknown how chromatin loops are organized along the genome and how proteins participating in DSB formation are tethered to the chromosome axes. Here, we identified three categories of axis-associated genomic sites: PRDM9 binding sites, where DSBs form, binding sites of the insulator protein CTCF, and H3K4me3-enriched sites. We demonstrated that PRDM9 promotes the recruitment of MEI4 and IHO1, two proteins essential for DSB formation. In turn, IHO1 anchors DSB sites to the axis components HORMAD1 and SYCP3. We discovered that IHO1, HORMAD1 and SYCP3 are associated at the DSB ends during DSB repair. Our results highlight how interactions of proteins with specific genomic elements shape the meiotic chromosome organization for recombination.
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Project description:Here we studied the budding yeast Lachancea kluyveri, a cousin of the model Saccharomyces cerevisiae, in order to try to understand the mechanism responsible for the absence of meiotic recombination on its almost entire sex chromosome (Brion et al. 2017). We performed meiotic DSB mapping using CC-seq (Gittens 2019). Briefly, we observed a distribution of meiotic DSBs mainly in gene promoters as in S. cerevisiae and a depletion within Lakl0C-left (the 1 Mb long domain on the sex chromosome with no meiotic recombination). Also, we noted a poor conservation of DSB hotspots strength between L. kluyveri and S. cerevisiae.
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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.
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