Figure 4.

ATM has only a small contribution to the persistent intra-S-phase checkpoint in DNA-PKcs–deficient cells. (A) Percentage of DNA synthesis over non-irradiated controls measured after exposure to 10 Gy of IR in the presence or absence of ATMi in M059K cells. (B) As in (A) in M059J cells. (C) As in (A) in V3 cells. Error bars represent the standard deviation from 3 independent experiments. The significance of differences between individual measurements is indicated by * symbol: * p < 0.05, ** p < 0.01, *** p < 0.001; n.s. non-significant.