Reagents
Labeled and unlabeled dNTPs/rNTPs and Sequenase were purchased from Amersham Pharmacia. M13mp18 and M13mp19 single-stranded circular DNA, T4 polynucleotide kinase, DNase I and the Klenow fragment were from TAKARA, Nuclease P1 was from Roche, and anti-FLAG M2 Ab (antibody)-agarose and FLAG peptide were from Sigma. SV40 T-antigen was purified from baculovirus-infected insect cells as reported (22). PriA helicase protein was provided by Dr Taku Tanaka (23). Oligonucleotides were purchased from Hokkaido system science Co., Ltd (Hokkaido, Japan), and were purified on polyacrylamide gel, followed by purification by Sep-Pak Plus C18 cartridge column (Waters).