REPAIR OF ULTRAVIOLET-LIGHT DAMAGE IN A VARIETY OF HUMAN FIBROBLAST CELL STRAINS

Abstract

Postreplication repair of DNA damage after UV light irradiation was examined in a wide variety of human fibroblast strains. The donors were patients with xeroderma pigmentosum (XP) of different complementation groups or other hereditary disorders with indications of radiosensitivity, or with light sensitivity or multiple cancers. The defect in postreplication repair previously found in XP variants (excision proficient XP) was observed in 5 XP variants and a less severe defect in postreplication repair was found in excision defective XP in complementation groups A, B, C and D. Complementation group E and all other cell strains studied showed a response that was not significantly different from that of cells from normal donors. Excision repair was also measured in some of these cell strains and was defective only in XP cells. UV cell survival characteristics were obtained for many of the cell strains. The most sensitive were cells from excision deficient XP and a sun sensitive child (11961). The latter had no measurable defect in excision of postreplication repair. The rest of the survival curves lay in a band limited by normal cell strains and the slightly more sensitive excision proficient XP variant XP30RO. Only in the case of the variants XP30RO and XP7TA was any influence of caffeine on cell survival shown.