Polymerases alpha, delta, and epsilon are most active in dividing cells, suggesting that they function in replication. In contrast, polymerase beta is active in nondividing and dividing cells suggesting that it may function primarily in DNA repair. Polymerase alpha also has primase activity in association with primase in many eukaryotic systems. May just be complexed with the primase in a polymerase a- primase complex. The primers are then extended by polymerase delta.
Suggestion is that it also untangles newly replicated loops of DNA in the chromosome of eukaryotes.
Nuceleosomes apparently form very rapidly following replication of the daughter strand. The synthesis of histones, therefore, must occur simulataneously with DNA replication. The extreme 5' ends of the eukaryotic chromosome cannot be replicated by DNA polymerase because of the requirement for 5' to 3' synthesis. Special mechanisms required. Telomeres consist of tandem repeats of simple-sequence DNA and they are replicated by the telomerase which catalyzes synthesis without a DNA template.