Figure 3.

Sequence selectivity of 1-Chl-induced DNA alkylation. (A) SV40 DNA alkylation induced by 1-Chl (0.001–1 µM) following prolonged incubation (18 h at 37°C). DNA alkylation lesions were converted to strand breaks as described in Materials and Methods. (B) Sequence selectivity of 1-Chl-induced SV40 DNA alkylation. Template DNA (0.3 µg) was either reacted with 1 µM 1-Chl for 18 h at 37°C (lane 6) or untreated (control, lane 5). Following extraction and ethanol precipitation, DNA samples (0.1 µg) were subjected to the RPE reaction using ³²P-end-labeled primers (starting from position 2818/reverse on the SV40 genome) and resolved on sequencing polyacrylamide gels as described in Materials and Methods. DNA fragments were visualized by phosphoimaging analysis. Arrows indicate 1-Chl binding sites, and GATC (lanes 1–4) represent results of sequencing reactions using the same DNA primers.