FIG. 1.

Various genotoxic drugs induce PARP cleavage but not necessarily a sub-G₁ population in FACS analysis. BL41 cells were treated for 16 h with genotoxins (cisplatin, 10 μg/ml; doxorubicin, 5 μg/ml; etoposide, 10 μg/ml; camptothecin, 3 μg/ml). (A) Cells were harvested at 4-h intervals and assessed for PARP cleavage by Western blotting: (0 h [tracks 1, 6, 11, and 16], 4 h [tracks 2, 7, 12, and 17], 8 h [tracks 3, 8, 13, and 18], 12 h [tracks 4, 9, 14, and 19], and 16 h [tracks 5, 10, 15, and 20]). (B) Samples were also subjected to FACS analysis for cell cycle distribution. Cell cycle profiles corresponding to time points at which PARP cleavage was judged to be 100% are shown.