Different activities of the largest subunit of replication protein A cooperate during SV40 DNA replication

Replication protein A (RPA) is a stable heterotrimeric complex consisting of p70, p32 and p14 subunits. The protein plays a crucial role in SV40 minichromosome replication. Peptides of p70 representing interaction sites for the smaller two subunits, DNA as well as the viral initiator protein large T-antigen (Tag) and the cellular DNA polymerase α-primase (Pol) all interfered with the replication process indicating the importance of the different p70 activities in this process. Inhibition by the peptide disrupting protein–protein interactions was observed only during the pre-initiation stage prior to primer synthesis, suggesting the formation of a stable initiation complex between RPA, Tag and Pol at the primer end