The function of DNA polymerases in DNA repair synthesis of ultraviolet-irradiated human fibroblasts.
Ultraviolet-induced DNA repair synthesis was measured in saponin-permeabilized normal human fibroblasts by the incorporation of [alpha-32P]dTMP into DNA. The involvement of DNA polymerases alpha, beta, delta, and epsilon in excision repair of pyrimidine dimers was examined using specific inhibitors. Dose-response curves resulting from experiments with up to 12 different inhibitor concentrations were analyzed by linear regression. Inhibitor concentrations at which repair activity was reduced to 50% were calculated. The following K50 values were found: aphidicolin, 0.2 microM; ddTTP, 12.5 microM; butylphenyl-dGTP, 7.6 microM; butylanilino-dATP, 6.0 microM. Comparison of K50 values with in vitro Ki values of DNA polymerases revealed that in permeabilized human fibroblasts reparative DNA synthesis is catalyzed by DNA polymerase delta and by DNA polymerase epsilon.
Popanda
O
O
Institute of Biochemistry, German Cancer Research Center, Heidelberg.
Thielmann
H W
HW
D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D004247:DNA / Q000528:radiation effects; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D005347:Fibroblasts / Q000201:enzymology / Q000528:radiation effects; D006801:Humans; D019384:Nucleic Acid Synthesis Inhibitors; D013938:Thymidine Monophosphate / Q000378:metabolism; D014466:Ultraviolet Rays
D019384:Nucleic Acid Synthesis Inhibitors; D013938:Thymidine Monophosphate; D004247:DNA; D004259:DNA-Directed DNA Polymerase