Photorepair of ultraviolet radiation-induced pyrimidine dimers in corneal DNA.
The induction and photorepair of pyrimidine dimers in DNA have been measured in the ultraviolet-irradiated, corneal epithelium of the marsupial, Monodelphis domestica, using damage-specific nucleases from Micrococcus luteus in conjunction with agarose gel electrophoresis. We observed that FS-40 sunlamps (280-400 nm) induced 7.2 +/- 1.0 X 10(-5) pyrimidine dimers per kilobase (kb) of DNA per J/m2. Following 100 J/m2, 50% and greater than 90% of the dimers were photorepaired during a 10- and 30-min exposure to photoreactivating light (320-400 nm), respectively. In addition, approximately 70% and approximately 60% of the dimers induced by 300 and 500 J/m2, respectively, were repaired by a 60-min exposure to photoreactivating light. The capacity of the corneal epithelium of M. domestica to photorepair pyrimidine dimers identifies this animal as a potentially useful model with which to determine whether pyrimidine dimers are involved in pathological changes of the irradiated eye.
Ley
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RD
Division of Biomedical Research, Lovelace Medical Foundation, Albuquerque, NM 87108.
Applegate
L A
LA
Freeman
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SE
D000818:Animals; D003315:Cornea / Q000378:metabolism* / Q000528:radiation effects; D004260:DNA Repair; D003720:Densitometry; D004307:Dose-Response Relationship, Radiation; D004587:Electrophoresis, Agar Gel; D004848:Epithelium / Q000378:metabolism / Q000528:radiation effects; D005453:Fluorescence; D008027:Light; D009893:Opossums; D010781:Photography; D011740:Pyrimidine Dimers / Q000378:metabolism*; D014466:Ultraviolet Rays
D011740:Pyrimidine Dimers