Of all mutations identified, T315I was the only exchange mediating full resistance to nilotinib. Mutations identified in the nilotinib screen were recreated in Bcr-Abl p185 using site-directed mutagenesis and expressed in Ba/F3 cells. After incubation for 24 and 48 hours without and in the presence of nilotinib at the indicated concentrations, proliferation was measured using an MTS-based method. At least 2 independent experiments were performed for each construct. Representative results of 1 experiment after 48 hours of incubation are shown. OD indicates optical density. Values are expressed as mean of triplicates. Bars are ± SE. S349L, although not identified in the screen, was included for comparison with Q252H and the Q252H/S349L double mutant.