Figure 3.

WRN stimulates the rate of incorporation of the initiating nucleotide by DNA pol δ. 0.5 pmol of the 14/46 primer/template was incubated with ≈0.3 fmol of pol δ in the absence (−) or presence (+) of 24 fmol of WRN. dGTP was included at concentrations ranging from 0.02–5 μM, and the reactions were incubated for either 5 min [(−)WRN] or 3 min [(+)WRN] at 37°C. The reactions were quenched by the addition of denaturing loading buffer and were electrophoresed through 14% polyacrylamide-urea gels as described in Materials and Methods. The extension products were visualized by autoradiography (A), and the amounts of 15-mer generated were quantitated by PhosphorImager analysis. The kinetic constants were derived from Hanes-Woolf plots of the data (B).