Effect of rifampicin on poxvirus protein synthesis

Poxvirus strains differ with respect to the effect of rifampicin on viral protein synthesis. Rifampicin severely depressed vaccinia-directed protein synthesis but had little effect on the rate of cowpox-directed protein synthesis, including one late virus-induced enzyme. The spectrum of polypeptides synthesized in cowpox-infected cells was similar in the presence or absence of rifampicin except for one significant difference. After removal of rifampicin, viruslike particles assembled to some extent, even when protein synthesis was inhibited by cycloheximide. However, reversal was more extensive if protein synthesis was allowed.