Fig. 2. Translesion synthesis by human pol η. Increasing amounts of pol α (4.7 and 23.6 fmol in lanes 2 and 3, respectively) or pol η (0.25, 1.4 and 7.1 fmol in lanes 5, 6 and 7, respectively) were incubated with the 5′-³²P-labeled primer–templates indicated beside each panel at 37°C for 15 min in the standard reaction mixture. Lanes 1 and 4 contained no enzyme. The products were subjected to polyacrylamide gel electrophoresis under denaturing conditions. The autoradiograms of the gels are shown. (A) Undamaged control for CPD and (6–4) photoproduct [(6–4)PP]. (B) CPD at the bridged TT. (C) The (6–4) photoproduct at the bridged TT. (D) The abasic analog at X. (E) Undamaged control for AAF. (F) AAF-modified guanine at the indicated site. (G) Undamaged control for cisplatin. (H) Intrastrand cross-link of two guanines by cisplatin at the indicated site.