Reactivation and mutagenesis of herpes virus in 5-azacytidine-treated monkey kidney cells

Enhanced survival of UV-damaged herpes simplex virus and Simian virus 40 was investigated in CV-1 monkey cells treated with inhibitors of DNA methylation such as 5-azacytidine and ethionine. Survival of UV-irradiated virus was higher in treated cells than in untreated cells. Survival of herpes virus irradiated with 60Co gamma-ray was not enhanced in the treated cells. The frequency of forward mutation of herpes virus increased in 5-azacytidine-treated cells. Relative content of methylcytosine was reduced in the cells treated with 5-azacytidine. Therefore a mechanism similar to UV-enhanced reactivation of virus was operating in the cells with hypomethylated DNA.