FIGURE 4.

The effect of Fen-1 on the abasic site bypasses by DNA polymerases δ and β are not dependent on the position of the lesion. The reactions were performed as described under “Experimental Procedures.” A, 60 nm DNA pol δ (lanes 1–5) or 30 nm DNA pol β (lanes 6–10) were incubated on the Gap-1 AP template, in the absence (lanes 1 and 6) or in the presence of 110 nm PCNA, either alone (lanes 2 and 7) or in combination with 25 nm RP-A (lanes 3 and 8) or 3 nm Fen-1 (lanes 4 and 9) or both (lanes 5 and 10). B, 30 nm DNA pol β were incubated for the indicated times on the Gap-1 AP template in the presence of PCNA and RP-A and in the absence (lanes 1–4) or in the presence (lanes 5–8) of 3 nm Fen-1. C, 30 nm DNA pol δ (lanes 1–8) or DNA pol β (lanes 9–16) were incubated on the 38 nt Gap control (lanes 1–4 and 9–12) or AP (lanes 5–8 and 13–16) template in the presence of PCNA and RP-A and in the absence (lanes 1, 5, 9, and 13) or in the presence (lanes 2–4, 6–8, 10–12, and 14–16) of increasing amounts of Fen-1. Asterisks mark the position of pausing sites during strand displacement DNA synthesis.