Fig. 5.

Caspase-2 contributes to IR-induced cell cycle arrest. (A and B) Cells stained positive for BrdU 24 h following γ-irradiation. Caspase-2^+/+ or caspase-2^−/− MEFs, and E1A/Ras-transformed caspase-2^+/+and caspase-2^−/− MEFs, were seeded onto glass coverslips and exposed to 10 Gy γ-irradiation. Twenty-four hours following γ-irradiation, cells were pulsed for 4 h with BrdU and BrdU +ve cells detected by immunostaining (A). Results in panel B are expressed as mean ± SEM from 3 experiments. *P < 0.005 for comparison between irradiated caspase-2^+/+ vs. caspase-2^−/− MEFs and E1A/Ras-transformed caspase-2^+/+and caspase-2^−/− MEFs.