FIG. 9.

Basal DNA polymerase activity of UL54 mutants. (A) The DNA polymerase activity of wild-type or mutant UL54 proteins expressed in reticulocyte lysates was measured by determining the incorporation of [³²P]dTTP into a poly(dA)-oligo(dT) DNA template. Samples were taken after 0, 10, 20, and 30 min of incubation at 37°C and spotted onto DE81 filters. The filters were washed, and the radioactivity was counted. (B) The values were normalized to the amount of in vitro-translated proteins (lower panel), as estimated by SDS-PAGE analysis and phosphorimager quantification. The graph (upper panel) shows the average of data from three independent experiments, together with the standard deviations.