EWSR1 regulates PRDM9-dependent histone 3 methylation and links recombinant hotspots to the chromosomal axis

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. Overall design: We performed ChIP-seq with antibodies against H3K4me3 and H3K36me3 using chromatin extracted from control, Prdm9 PR/SET domain mutant and Ewsr1 conditional knockout mouse spermatocytes, and compared it to previously generated ChIP-seq data for H3K4me3 and H3K36me3 in the same cell type. We also performed ChIP-seq with antibody against single strand DNA binding protein DMC1 in spermatocytes isolated from control, Prdm9 PR/SET domain mutant, Prdm9 heterozygous and Ewsr1 conditional knockout mouse to analyze meiotic DNA double strand formation level