Effect of actinomycin D and guanidine on the formation of a ribonucleic acid polymerase induced by foot-and mouth-disease virus and on the replication of virus and viral ribonucleic acid.

The RNA-dependent RNA polymerase induced in baby-hamster kidney cells by infection with foot-and-mouth-disease virus can be detected as early as 60min. after infection, which is 60min. before viral RNA synthesis commences. The time at which the polymerase can first be detected coincides with the latest time at which actinomycin D (50mug./10(7) cells) or guanidine (1mg./10(7) cells) inhibits virus replication. However, by increasing the concentration of guanidine, viral replication can be inhibited later in the growth cycle, casting doubt on the validity of the hypothesis that guanidine acts specifically on the formation of the viral RNA polymerase.