Evidence implying DNA polymerase beta function in excision repair.
Comparison was made of the ability of calf thymus DNA polymerases alpha and beta to replicate the following templates: native E. coli CR-34 DNA (T-DNA), calf thymus DNA activated by DNase I (act.DNA), BU-DNA (from E. coli CR-34 cells cultured on BUdR-containing medium) with damages resulting from incomplete excision repair, as well as thermally denatured act.DNA and BU-DNA (s.s.act.DNA and s.s.BU-DNA). 3H-TTP incorporation during extensive replication of act.DNA was similar for both enzymes, being, as expected, 40 times higher than for T-DNA. Likewise, the differences in the yield of the s.s.act.DNA or s.s.BU-DNA replication between both enzymes were negligible. In contrast, damaged native DNA was 6 - 30 times more extensively replicated by DNA polymerase beta than alpha. We propose that this is due to the greater ability of DNA polymerase beta compared with alpha to replicate single-stranded gaps, the presence of which is more likely in damaged BU-DNA than in T-DNA and act.DNA.
D000818:Animals; D002417:Cattle; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D004256:DNA Polymerase I / Q000378:metabolism*; D004257:DNA Polymerase II / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003850:Deoxyribonuclease I; D003851:Deoxyribonucleases / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D007700:Kinetics; D013698:Templates, Genetic; D013950:Thymus Gland / Q000201:enzymology*
D004254:DNA Nucleotidyltransferases; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004259:DNA-Directed DNA Polymerase; D003851:Deoxyribonucleases; D004720:Endonucleases; D003850:Deoxyribonuclease I