Leakage induced in Escherichia coli cells by A protein-RNA complexes from bacteriophage f2.

Complexes of f2 phage RNA and its A protein, or maturation protein, transfect Escherichia coli cells much better than does protein-free RNA. We used these complexes to introduce the bacteriophage f2 lysis gene into cells. The A protein-RNA complex was found to kill cells, probably by causing them to leak large macromolecules. Previously induced beta-galactosidase leaked from cells treated either with the A protein-RNA complex or with lethal but noninfectious complexes that had been treated with formaldehyde. This observation was consistent with an earlier finding that formaldehyde-treated f2 RNA stimulates the in vitro synthesis of a lysis protein. The complexes did not stimulate the rate of leakage of beta-galactosidase from a streptomycin-resistant mutant known to be lysis defective. On the other hand, the rate of leakage was increased in a double mutant resistant to both streptomycin and rifampin and which is lysed normally by f2 bacteriophage.