One pyrimidine dimer inactivates expression of a transfected gene in xeroderma pigmentosum cells

摘要: Abstract We have developed a host cell reactivation assay of DNA repair utilizing UV-treated plasmid vectors. The primarily reflects cellular transcriptional activity damaged measured indirectly as enzyme the transfected genes. We studied three plasmids (pSV2cat, 5020 base pairs; pSV2catSVgpt, 7268 and pRSVcat, 5027 pairs) with different sizes promoters carrying bacterial cat gene (CAT, chloramphenicol acetyltransferase) in construction that permits expression human cells. All simian virus 40-transformed cells expressed high levels gene. UV treatment prior to transfection resulted differential decrease CAT lines. With inactivation was greater xeroderma pigmentosum group A D lines (D0 = 56 J X m-2) than other tested (normal, ataxia-telangiectasia, Lesch-Nyhan, retinoblastoma)(D0 680 m-2)(D0 is dose reduces percentage by 63% along exponential portion dose-response curve). D0 curve 50 m-2 for pSV2cat pRSVcat similarity data size implies they all similar UV-inactivation target size. UV-induced pyrimidine dimer formation quantified number T4 endonuclease V-sensitive sites. In most sensitive cells, plasmids, one inactivates about 2 kilobases, close putative mRNA.