Correlation of increased nuclease activity with enhanced virus reactivation

An increase in nuclease activity, which degraded both unirradiated and ultraviolet (UV)-irradiated DNA, was observed in the extract of monkey Vero cells after irradiation with an appropriate amount of UV. In contrast, no increase was observed with mouse L cells. Neither DNA polymerases nor uracil-DNA glycosylase was enhanced but rather suppressed by UV irradiation in both cell lines. Cytological studies showed that, in Vero cells, the reactivation of UV-irradiated herpes simplex virus was markedly enhanced by irradiating cells with UV before infection. However, no enhancement was observed with L cells. These results suggest that an increase in nuclease activity may be one of underlying mechanisms for the enhanced reactivation of DNA viruses