INHIBITION OF THE INTRACELLULAR-TRANSPORT OF INFLUENZA VIRAL-RNA BY ACTINOMYCIN-D

In primary chicken embryo cells infected with fowl plague virus additi on of actinomycin D at defined times during the infection cycle has di fferent consequences on viral replication. If actinomycin D is added i mmediately after infection with a concentration, which inhibits viral RNA synthesis only partially, it interferes with the nucleo-cytoplasmi c transport of all viral RNA species (mRNA and vRNA) so far tested. If actinomycin D is present during infection (adsorption, penetration an d uncoating) no viral RNA is synthesized, and the nucleocapsid of the infecting virus does not reach the nucleus, as shown by fluorescent an tibodies. Therefore the primary effect of actinomycin D on influenza v irus replication is on the transport of the incoming vRNPs from the cy toplasm to the cell nucleus, which is the cell compartment where trans cription takes place.