FIG. 4.

T-antigen-mediated priming and elongation activity of the pol-prim trimer in the presence of RPA. Reaction mixtures contained 25 ng of M13 DNA, 300 ng of T antigen as indicated (+), 200 ng of tetramer (A), 250 ng of trimer (B and C), and 500 to 1,000 ng of RPA (A), 1,000 ng of RPA (B), or 50 to 300 ng of E. coli SSB (C). Where indicated, 250 ng of p68 was added to the reaction (B and C). Radiolabeled elongation products were detected by alkaline agarose electrophoresis and autoradiography. The radioactivity (counts per minute [cpm]) incorporated in each reaction is shown below each lane. Products made in control reactions without pol-prim, T antigen, RPA, or SSB are indicated (−). The mobilities of end-labeled marker DNA fragments of the indicated lengths in nucleotides are shown at the right.