An SV40-transformed xeroderma pigmentosum group D cell line: establishment, ultraviolet sensitivity, transfection efficiency and plasmid mutation induction.

Fibroblasts from a patient with xeroderma pigmentosum complementation group D were treated with Simian virus 40 to establish a transformed cell line suitable for studies of DNA-mediated gene transfer. After progressing through 2 crises, a stable line, XP6Be(SV40), was established and cultured for more than 1 year. This line retains the characteristic xeroderma pigmentosum ultraviolet hypersensitivity and is able to complement a SV40-transformed group A line when fused and assayed for ultraviolet radiation inhibition of colony-forming ability. XP6Be(SV40) expressed high levels of transfected chloramphenicol acetyltransferase activity (0.1 nmole X mg-1 X min-1) in a transient expression assay, showed stable expression of transfected gpt or neo genes (frequency 1-20 X 10(-5)), and permitted replication of the mutagenesis shuttle vector plasmid, pZ189. Ultraviolet treatment (500 J X m-2) of pZ189 prior to replication in XP6Be(SV40) resulted in a large reduction in plasmid yield (5% survival) and a 60-fold increase in the mutation frequency, reflecting the reduced ability of these cells to repair ultraviolet-damaged transfecting DNA. This cell line provides the opportunity to utilize transfection studies in cells with the xeroderma pigmentosum group D defect in excision repair.