Figure 2.

Induction of apoptosis by drug treatment. (a) HOECHST 33258–stained cells analyzed by fluorescence microscopy after 96 hours of treatment with adriamycin. (b) Time course of cell death after treatment with 0.34 μM adriamycin. (c) Cell death after 60 hours of treatment with 5-FU. Two different heterozygous cell lines (A and B) were assayed. (d) Time course of cell death after treatment with 375 μM 5-FU. Cells marked +/– had 1 allele of the indicated gene disrupted and were the parents of the cells with both alleles disrupted (–/–).