DNA synthesis on UV irradiated model templates using human DNA polymerases alpha and beta: primer slippage to account for evident transdimer continuity in product.
We have studied the comparative behavior of human DNA polymerases alpha and beta on a polynucleotide template of dT100 with dA15 covalently attached at the 3' end to serve as primer when defined numbers of pyrimidine dimers are introduced by UV (254 nm) irradiation. We have obtained the surprising result that with both alpha and beta polymerases the incorporation of labelled dATP is enhanced when the template has been irradiated (maximum value at 1000 J/m2 UV incident dose). In the presence of Mn2+, DNA polymerase beta produces a product size corresponding to full copying of the template whether irradiated or not. In marked contrast DNA polymerase alpha produces only short products on unirradiated strands but full copying of irradiated templates. Evidently both polymerases utilize a much larger fraction of the template pool following UV irradiation.
D004256:DNA Polymerase I / Q000378:metabolism*; D004257:DNA Polymerase II / Q000378:metabolism*; D004261:DNA Replication / Q000528:radiation effects*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007700:Kinetics; D011061:Poly A; D011071:Poly T; D011740:Pyrimidine Dimers / Q000032:analysis; D013698:Templates, Genetic; D014466:Ultraviolet Rays
D011740:Pyrimidine Dimers; D011061:Poly A; D011071:Poly T; C015465:poly(dA); D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004259:DNA-Directed DNA Polymerase