Abnormal mutation frequencies in human repair-defective hybrid cell lines.
Two intraspecific human cell hybrids, HD2 and HD1A, produced from fusion between HeLa cells and xeroderma pigmentosum fibroblasts, express XPD-like rates of excision repair and hypersensitivity to UV-radiation. In the present paper we describe unusual patterns of UV-induced mutation in both cell lines. Though HD2 very closely resembles XPD both phenotypically and genetically, in UV-dose response it is hypomutable at the loci for ouabain and diphtheria toxin resistance. At equitoxic dose, however, it shows normal mutability, HD1A, by contrast, is hypermutable as a function either of UV dose or in terms of equitoxicity for these genes. HD1A's mutator phenotype is a dominant characteristic and is not associated with grossly abnormal DNA precursor pool imbalance. The possibility remains that DNA polymerase infidelity underlies its hypermutability.
D002455:Cell Division / Q000528:radiation effects; D002460:Cell Line; D004260:DNA Repair; D004167:Diphtheria Toxin / Q000494:pharmacology; D004351:Drug Resistance / Q000187:drug effects; D006801:Humans; D006822:Hybrid Cells / Q000502:physiology; D009154:Mutation / Q000528:radiation effects; D010042:Ouabain / Q000494:pharmacology; D014466:Ultraviolet Rays
D004167:Diphtheria Toxin; D010042:Ouabain