Figure 6.

Activity of both mouse extracts against dU (lanes 1–6) and the AP site (lanes 7–12). The AP site was obtained by treating the dU-containing oligomer with purified UDG. The AP site was then created and incubated with testes cell-free extracts from both wt and ko mice. Lanes 7 and 10 illustrate the lability of the AP site under experimental conditions in the absence of any added enzyme. For this reason the purified HAP1 was added to the reaction mixture in Fig. 5.