PRDM9 is a zinc finger protein that binds DNA at specific locations in the genome and alleles influence human chromosomal rearrangements, causing hereditary diseases. MRK-740 is a potent selective and cell-active PRDM9 inhibitor with an IC50 of 80 nM. In cells, MRK-740 specifically and directly inhibits H3K4 methylation at endogenous...