Repair of pyrimidine dimer ultraviolet light photoproducts by human cell extracts.
A newly developed method allows human cell extracts to carry out repair synthesis on ultraviolet light irradiated closed circular plasmid DNA [Wood, R. D., Robins, P., & Lindahl, T. (1988) Cell 53, 97-106]. The identity of the photodamage that leads to this repair replication was investigated. Removal of stable pyrimidine hydrates from irradiated plasmid pAT153 did not significantly affect the amount of repair replication in the fluence range of 0-450 J/m2, because of the low yield of these products and their short DNA repair patch size. Photoreactivation of irradiated DNA using purified Escherichia coli DNA photolyase to remove more than 95% of the cyclobutane dimers from the DNA reduced the observed repair synthesis by 20-40%. The greater part of the repair synthesis is highly likely to be caused by (6-4) pyrimidine dimer photoproducts. This class of lesions is rapidly repaired by mammalian cells, and their removal is known to be important for cell survival after ultraviolet irradiation.
Wood
R D
RD
Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, U.K.
D002457:Cell Extracts / Q000494:pharmacology; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism* / Q000528:radiation effects; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D004706:Endodeoxyribonucleases / Q000378:metabolism; D006801:Humans; D008190:Lyases / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D009699:N-Glycosyl Hydrolases / Q000378:metabolism; D010957:Plasmids / Q000528:radiation effects*; D011740:Pyrimidine Dimers / Q000378:metabolism*; D014466:Ultraviolet Rays
D002457:Cell Extracts; D004269:DNA, Bacterial; D009097:Multienzyme Complexes; D011740:Pyrimidine Dimers; C032219:UV endonuclease; D004706:Endodeoxyribonucleases; D009699:N-Glycosyl Hydrolases; D008190:Lyases; D004255:Deoxyribodipyrimidine Photo-Lyase