DNA polymerase activity in a repair-deficient human cell line.
A human low-density-lipoprotein (LDL) receptor-deficient diploid fibroblast cell line (GM1915) was determined to be short patch competent (DNA polymerase-beta) and long patch deficient (DNA polymerase-alpha) for DNA excision repair. Analysis of DNA from GM1915 cells or from WI38 control cells, following treatment with a mutagen known to initiate long patch excision repair, showed that GM1915 cells exhibited decreased resynthesis of oligonucleotide segments excised during repair. When cells deficient in DNA polymerase-alpha activity were permeabilized to permit LDL entry, repair synthesis immediately increased. These data suggest that DNA polymerase-alpha is not activated by mutagen treatment in GM1915 cells and that introduction of LDL into the cells results in activation of the enzyme.
D002460:Cell Line; D004260:DNA Repair / Q000187:drug effects; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000201:enzymology*; D006801:Humans; D006937:Hypercholesterolemia / Q000201:enzymology; D008077:Lipoproteins, LDL / Q000378:metabolism; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D011973:Receptors, LDL / Q000032:analysis
D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D008741:Methyl Methanesulfonate; D004259:DNA-Directed DNA Polymerase