Expression of early virus functions in human cytomegalovirus infected HEL cells: effect of ultraviolet light-irradiation of the virus.

Ultraviolet (u.v.) light-irradiation of human cytomegalovirus (HCMV) resulted in differential inactivation of virus capacities, e.g. induction of cell rounding, early antigens (EA), nuclear inclusion, HCMV DNA synthesis, cellular DNA synthesis, HCMV-specific DNA polymerase, cellular DNA polymerases and plaque production, while the capacity of HCMV to penetrate cell nuclei was not critically impaired. These results indicated that the virus-coded functions expressed after infection were responsible for sll these events except for HCMV-induced stimulation of cellular RNA synthesis which was enhanced by irradiation of the virus at a low dose of u.v. light (6600 ergs/mm2). In these experiments phosphonoacetic acid was effectively utilized to detect EA formation by immunofluorescent staining and to differentiate cellular DNA synthesis from virus DNA synthesis.