Expression of a mammalian DNA photolyase confers light-dependent repair activity and reduces mutations of UV-irradiated shuttle vectors in xeroderma pigmentosum cells.
Photoreactivation is one of the DNA repair mechanisms to remove UV lesions from cellular DNA with a function of the DNA photolyase and visible light. Two types of photolyase specific for cyclobutane pyrimidine dimers (CPD) and for pyrimidine (6-4) pyrimidones (6-4PD) are found in nature, but neither is present in cells from placental mammals. To investigate the effect of the CPD-specific photolyase on killing and mutations induced by UV, we expressed a marsupial DNA photolyase in DNA repair-deficient group A xeroderma pigmentosum (XP-A) cells. Expression of the photolyase and visible light irradiation removed CPD from cellular DNA and elevated survival of the UV-irradiated XP-A cells, and also reduced mutation frequencies of UV-irradiated shuttle vector plasmids replicating in XP-A cells. The survival of UV-irradiated cells and mutation frequencies of UV-irradiated plasmids were not completely restored to the unirradiated levels by the removal of CPD. These results suggest that both CPD and other UV damage, probably 6-4PD, can lead to cell killing and mutations.
Asahina
H
H
Radiation Biology Center, Kyoto University, Yoshida-konoecho, Sakyo-ku, Kyoto, Japan.
Han
Z
Z
Kawanishi
M
M
Kato
T
T
Ayaki
H
H
Todo
T
T
Yagi
T
T
Takebe
H
H
Ikenaga
M
M
Kimura
S H
SH
D001483:Base Sequence; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D004260:DNA Repair / Q000528:radiation effects*; D018076:DNA, Complementary / Q000235:genetics; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics* / Q000528:radiation effects; D010957:Plasmids / Q000528:radiation effects; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000201:enzymology* / Q000235:genetics*
D018076:DNA, Complementary; D012333:RNA, Messenger; C098727:pyrimidine(6-4)pyrimidone photolyase; D004255:Deoxyribodipyrimidine Photo-Lyase