An inhibitor of potentially lethal damage (PLD) repair reduces the frequency of gamma-ray-induced mutations in cultured Chinese hamster V79 cells.
Cordycepin (3'-deoxyadenosine, 3'-dA) is an RNA antimetabolite and a radiosensitizer in cultured mammalian cells. In the present paper, the effects of 3'-dA on gamma-ray-induced lethality and 6-thioguanine (6TG)-resistant mutations in cultured Chinese hamster V79 cells were examined. 3'-dA had the effect of sensitizing the lethality induced by gamma-rays. The potentially lethal damage (PLD) repair produced by post-incubation of cells in Hanks' solution after gamma-irradiation was almost completely suppressed by 5 x 10(-5) M 3'-dA. When cells were irradiated with 10 Gy gamma-rays and incubated with 3'-dA for 5 h, the frequency of 6TG-resistant mutations induced by gamma-rays decreased to one-sixth of that of irradiated cells incubated without 3'-dA. The decrease in the frequency of gamma-ray-induced mutations was dependent on the length of incubation time with 3'-dA. It is suggested that the inhibition of PLD repair by 3'-dA may be that of error-prone repair.
Yokoiyama
A
A
Laboratory of Mutagenesis, National Institute of Genetics, Mishima, Japan.
Kada
T
T
Kuroda
Y
Y
D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair / Q000187:drug effects*; D003839:Deoxyadenosines / Q000494:pharmacology*; D005720:Gamma Rays; D008168:Lung / Q000166:cytology / Q000528:radiation effects; D009154:Mutation / Q000187:drug effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D013866:Thioguanine
D003839:Deoxyadenosines; D011838:Radiation-Sensitizing Agents; D013866:Thioguanine; C058120:cordycepin