Fig. 4.

ATR does not play a role in survival in response to NK314. A, ATR wild-type 1BRhTERT and ATR-deficient F02-98hTERT Seckel cells were incubated with various concentrations of NK314 for 24 h. The insert shows immunoblotting of ATR and β-actin (loading control) in these two cell lines. B, ML-1 cells were incubated with various concentrations of NK314 in the presence or absence of 100 nM UCN-01 for 24 h. For experiments in A and B, colonies were counted after eight doubling times. Each data point represents the mean ± S.E.M. of triplicate samples. C, ATR phosphorylation level does not change in response to NK314. HeLa cells were exposed to 50 and 100 nM NK314 for 24 h, and lysates were subjected to SDS-polyacrylamide gel electrophoresis and then immunoblotting with indicated antibodies.