Non-specific incision of DNA due to the presence of 8-methoxypsoralen photoinduced interstrand cross-links in Saccharomyces cerevisiae.
The repair of DNA interstrand cross-links (CL) induced by 8-methoxypsoralen (8-MOP) plus UVA irradiation was analyzed by the alkaline step elution technique. A double-exposure protocol was used with 8-MOP, starting with exposure to monochromatic 405-nm radiation inducing only DNA monoadducts (MA), followed, after washing out of unbound 8-MOP molecules, by a second exposure to 365-nm radiation inducing varying relative amounts of CL at a constant level of total photoadducts. In the range of doses used for the second exposure, repair of CL took place; however, in the presence of increased relative amounts of CL induced non-specific incision of DNA occurred. This endonucleolytic cleavage appears to be related to the increased mutagenic and recombinogenic effects observed at increased levels of CL.
Cundari
E
E
Centro Genetica Evoluzionistia CNR, Istituto di Genetica, Rome, Italy.
Polasa
K
K
Dardalhon
M
M
Youssefi
A A
AA
Averbeck
D
D
D003432:Cross-Linking Reagents / Q000494:pharmacology; D004249:DNA Damage; D004271:DNA, Fungal / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D008730:Methoxsalen / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics
D003432:Cross-Linking Reagents; D004271:DNA, Fungal; D008730:Methoxsalen