Project description:DNA Double Strands Breaks (DSBs) are highly detrimental since they can lead to mutations and chromosomes rearrangements (amplification, deletion, translocation and chromosome loss). Here, we used in a standardized system, where multiples DSBs are induced at defined positions across the human genome (U2OS-DIvA cells), to describe the distribution of eighteen histone modifications before and after damage using ChIP-Seq. This provides a comprehensive picture of the chromatin landscape induced at DSBs.
Project description:The Spo11-generated double-strand breaks (DSBs) that initiate meiotic recombination are non-randomly distributed across the genome. Here, we use Spo11-oligonucleotide complexes to map the distribution of meiotic DSBs in a spo11 mutant strain of Saccharomyces cerevisiae.
Project description:Doxorubicin is a widely used chemotherapeutic drug that intercalates between DNA base-pairs and posions Topoisomerase II, although the mechanistic basis for cell killing remains speculative. Here we show that both anthracyclines and Topoisomerase II poison cause enhanced DNA double-strand breaks around CpG island promoters of active genes genome-wide. We propose that torsion-based enhancement of nucleosome turnover exposes promoter DNA, ultimately causing DNA breaks around promoters that contributes to cell killing. We have analyzed mouse squamous cell carcinoma cells treated with doxorubicin, aclarubicin and etoposide. The direct in situ Breaks Labeling, Enrichment on Streptavidin (BLESS, PMID 23503052) method was used for mapping DNA double-strand breaks genome-wide.
Project description:The Spo11-generated double-strand breaks (DSBs) that initiate meiotic recombination are non-randomly distributed across the genome. Here, we use Spo11-oligonucleotide complexes, a byproduct of DSB formation, to map the distribution of meiotic DSBs in pch2 and sir2 mutant strains of Saccharomyces cerevisiae.
Project description:Mapping physiological double strand breaks (DSBs) in cancer cells uncovers transcription-coupled repair mechanism at oncogenic super-enhancers in which RAD51 of the homologous recombination pathway plays a key role supporting the hyper-transcription of related oncogenes.
Project description:High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (γH2AX), which occurs around DNA double-strand breaks and contributes to their repair. By chromatin immunoprecipitation using anti-γH2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of double–strand breaks induced by high NaCl, γH2AX is predominantly localized to regions of the genome devoid of genes (“gene deserts”), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes.
Project description:In relation with the study of the meiotic dynamic of H3K4 methylation, we determined the meiotic Double Strand Breaks (DSB) profiles of wild-type and set1∆ cells.