Identification of PRDM9 partners

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.