Replication of mycoplasmavirus MVL51. IV. Inhibition of viral synthesis by rifampin.

The effect of rifampin on the replication of MVL51, a bullet-shaped mycoplasmavirus with single-stranded circular DNA of molecular weight 2 X 10(6), has been examined in a rifampin-resistant host cell. Rifampin does not block the early steps in MVL51 infection but does decrease the total amount of parental viral DNA taken up. The single-stranded parental viral DNA that enters the cell is found in membrane-associated, double-stranded DNA replicative forms I and II. Rifampin had no significant effect on the synthesis of progeny viral DNA RFI and RFII early in infection and SSI (single-stranded progeny viral chromosomes) later in infection. The rifampin block in virus synthesis was found to be in the step converting SSI into assembled virions. Rifampin was shown to affect the synthesis of virus-specific RNA, Which suggests that viral transcription is necessary for virion assembly.