DNA replication is initiated at a region on a chromosome called an origin of replication. An enzyme called T-antigen (helicase) binds to the origin and unwinds the DNA in both directions from the origin. As the DNA is unwound specific single stranded DNA binding proteins (Replication factor A) prevent the strands from reannealing. RNA primers are produced by primase which bind to the DNA. Then DNA polymerase binds and begins to synthesize DNA complementary to the parental strand. DNA synthesis involved the incorporation of complementary bases into the growing strands of DNA. |