Microinjection of Micrococcus luteus UV-endonuclease restores UV-induced unscheduled DNA synthesis in cells of 9 xeroderma pigmentosum complementation groups.
The UV-induced unscheduled DNA synthesis (UDS) in cultured cells of excision-deficient xeroderma pigmentosum (XP) complementation groups A through I was assayed after injection of Micrococcus luteus UV-endonuclease using glass microneedles. In all complementation groups a restoration of the UV-induced UDS, in some cells to the repair-proficient human level, was observed. Another prokaryotic DNA-repair enzyme, T4 endonuclease V, restored the UV-induced UDS in a similar way after microinjection into XP cells. Since both enzymes specifically catalyse only the incision of UV-irradiated DNA, we conclude that this activity is impaired in cells of all 9 excision-deficient XP complementation groups tested.
D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000528:radiation effects*; D004260:DNA Repair; D004706:Endodeoxyribonucleases / Q000008:administration & dosage; D005816:Genetic Complementation Test; D006801:Humans; D008837:Micrococcus / Q000201:enzymology; D008845:Microinjections; D009097:Multienzyme Complexes / Q000008:administration & dosage*; D009699:N-Glycosyl Hydrolases; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000201:enzymology / Q000235:genetics*
D009097:Multienzyme Complexes; C032219:UV endonuclease; D004247:DNA; D004706:Endodeoxyribonucleases; C026044:deoxyribonuclease V; D009699:N-Glycosyl Hydrolases