Figure 4.

KARP-1 induction is dependent on functional p53 and ATM gene products. (A) HCW-2 (p53^−/−) and (B) HeLa (p53-defective) cell lines were x-irradiated at the indicated doses and at 90 min postirradiation RT-PCR reactions (β-actin) followed by Southern hybridizations (KARP-1) were performed as described. (C) GM08436A (ATM^−/−), (D) GM01526E (ATM^−/−), and (E) GM00130C (ATM^+/+) cells were x-irradiated at 10 Gy and at the indicated times postirradiation RT-PCR reactions (β-actin) followed by Southern hybridizations (KARP-1) were performed as described.