MS2177 is a potent and selective inhibitor of SETD8, the only methyltransferase known to catalyze monomethylation of histone H4 lysine 20 (H4K20). MS2177 has an in vitro IC50 of 1.9 μM (σ = 1.05 μM, n = 4) in ascintillation proximity assay. Binding of MS2