Functional expression of individual plasmid-coded RNA bacteriophage MS2 genes.

The genes of the RNA-containing bacteriophage MS2 were individually inserted into thermoinducible expression plasmids under control of the phage lambda P(L) promoter. Three phage-coded proteins (A-protein, coat protein, and replicase) were expressed at high efficiency. Induced cultures specifically complemented superinfecting amber mutants of phage MS2. Regulatory mechanisms operative during the natural infection cycle of the phage were reproduced by the plasmid expression system.