FIG 5.

PUBS stimulates the DNA replication activity of the E1Δ protein. (A) DNA replication activities of the indicated E1 proteins measured in cells transfected with increasing amounts of E1 expression vector (2.5, 5, 20, 25, and 50 ng). DNA replication activity is reported as a percentage of the maximal signal obtained with WT E1, which was set at 100%. Each value represents the average from two independent experiments, each performed in triplicates, with the standard deviation indicated by an error bar. (B) DNA replication activities of the indicated E1 proteins measured at different times posttransfection (24, 48, and 72 h). (C) Overexpression of the E1 UBS inhibits DNA replication supported by the PUBS-E1Δ protein. Levels of DNA replication, catalyzed by the PUBS-E1Δ protein, in C33A cells transfected with increasing amounts of E1 UBS-YFP expression vector (1.6 to 50 ng in 2-fold increments). A mutant UBS defective for UAF1 binding (WF mutant) was used as a specificity control. DNA replication activity is reported as a percentage of the signal obtained with YFP alone as a negative control. Each value is the average from two independent experiments, each performed in triplicates, with the standard deviation indicated by an error bar.