Figure 4.

PCNA increases the processivity of strand displacement-coupled DNA synthesis by pol δ. (A) Pol δ (0.1 unit) was incubated in the presence of 12 nM (3′-OH ends) 72–5′-³²P-labeled 17-mer template-primer under the conditions described in Materials and Methods for single turnover synthesis. Reactions were stopped at the indicated time points and the products were resolved on a 14% PAA/7 M Urea gel. Linear 5′-labeled 70- and 17-mer markers migrated at the positions indicated by arrows. (B) Pol δ (0.1 unit) was incubated in the presence of 12 nM (3′-OH ends) 72:17-mer template-primer in the absence or presence of RP-A (16 nM), RF-C (0.02 unit), and PCNA (1 μM as trimer), under the conditions described in Materials and Methods. Reactions were stopped at the indicated times and the products were resolved on a 14% PAA/7 M Urea gel. Arrows indicate the position of 85- and 17-mer markers, as well as the length of the different products synthesized.