Effects of UV-irradiation upon Venezuelan equine encephalomyelitis virus.

Venezuelan equine encephalomyelitis virus labelled with [14C]aminoacids or [3H]uridine was purified and UV-irradiated. The irradiation led to the formation of uracil photodimers and the covalent linking of the nucleocapsid protein C to virion RNA. The inactivation of infectivity correlated with the formation of uracil dimers, whereas the RNA-protein links were formed at much higher doses of UV irradiation.