FIGURE 3.

Cells expressing FLAG-KAP-1 S473A are sensitive to DNA damage. A and B, colony survival in HeLa cells. Cells were transfected with FLAG-CMV, FLAG-KAP-1 WT, or FLAG-KAP-1 S473A and treated with the indicated dose of IR (A) or camptothecin (B). Cells were left to form colonies for 10 days before staining with methylene blue. The data shown represent the average and S.E. of three independent experiments. C, HeLa cells were transfected with FLAG-CMV, FLAG-KAP-1 WT, or FLAG-KAP-1 S473A and treated with IR (6 Gy). Cell extracts were taken at 0.5 and 2 h after IR and immunoblotted with the indicated antibodies. P-KAP-1, phospho-KAP-1; P-ATM, phospho-ATM.