INDUCTION OF VIRUS-SPECIFIC PROTEINS IN SILKWORM BMN CELL-CULTURE AFTER INFECTION WITH NUCLEAR POLYHEDROSIS-VIRUS

The dynamics of induction of virus-specific proteins in silkworm BmN c ell culture after infection with nuclear polyhedrosis virus has been s tudied. Incubation of virus-infected cells in the presence of 0.3 mu g /ml aphidicolin resulted in inhibition of synthesis of late viral prod ucts and, in particular, of virus-specific DNA-polymerase and very lat e major viral proteins such as p10 protein and polyhedrin. Infection o f BmN cells with virus was not accompanied by an increase in activity of host cell DNA-polymerase alpha, and the presence of aphidicolin in the incubation medium did not effect the activity of this enzyme. Indu ction of an endonuclease specific to single-stranded DNA in infected c ells was shown. The endonuclease activity was maximal 40 h after infec tion, and activity of the virus-specific DNA-polymerase was maximal 60 h after infection. Retardation of the induction of the endonuclease i n cells incubated in the presence of aphidicolin suggests that this en zyme is a late viral product. The dynamics of induction of a virus-spe cific protein kinase detected earlier in infected silkworm pupae corre sponded to that of the very late viral product polyhedrin. Induction o f the protein kinase was inhibited by aphidicolin; this suggests that the protein kinase is also a late viral protein.