Figure 2.

Formation of DNA interstrand cross-links on SV40 DNA by 1-Chl, polyamide 1 and Chl. (A) Dose dependence. SV40 DNA was incubated at 37°C for 1 h with 10 µM of Chl (lane 3) polyamide 1 (lane 4) or 0.1–10 µM 1-Chl (lanes 5–7). (B) Time dependence. SV40 DNA was incubated at 37°C with 10 µM 1-Chl for 0, 5, 15 and 60 min (lanes 3–6). Lanes 1 and 2 represent native, double-stranded (ds) and denatured, single-stranded (ss) control SV40 DNA, respectively. Linearized and [³²P] end-labeled SV40 DNA was treated with agents, purified, denatured and resolved on neutral agarose gels as described in Materials and Methods. The percentage of double-stranded and resistant to denaturation cross-linked DNA was determined by phosphoimaging analysis of dried gels. The data points in the charts represent the average of at least two independent experiments.