Repair of 8-methoxypsoralen + UVA-induced damage in specific sequences in chromosomal and episomal DNA in human cells.
A study of the repair of DNA damage in the dihydrofolate reductase (dhfr) gene of SV40-transformed human fibroblasts after treatment with 8-methoxypsoralen (8MOP) and UVA is described. 8MOP+UVA-induced cross-links in the dhfr gene were completely repaired by 12 h in one normal and one Fanconi's anaemia (FA) group A cell line. In contrast, approximately 35% of cross-links in an episomally maintained Epstein--Barr virus derived plasmid remained unrepaired even after 48 h. Cross-linkable monoadducts in the dhfr gene were repaired more slowly than cross-links, and there was no detectable repair of cross-linkable monoadducts in the plasmid. Thus the ability of a cell to repair 8MOP+UVA-induced cross-links or cross-linkable monoadducts in an episome does not reflect its capacity to repair such lesions in genomic DNA.
Dean
S W
SW
MRC Cell Mutation Unit, University of Sussex, Falmer, Brighton, UK.
D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004247:DNA / Q000187:drug effects / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D005199:Fanconi Anemia; D005796:Genes / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D008730:Methoxsalen / Q000494:pharmacology*; D013539:Simian virus 40 / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*; D014466:Ultraviolet Rays
D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase; D008730:Methoxsalen