Control of bacteriophage RNA synthesis in Escherichia coli

Abstract

The control of f2 bacteriophage RNA synthesis has been studied by labelling infected Escherichia coli with radioactive uracil during a period of restriction of amino acid or shift-down of energy source. Following encapsulation of phage RNA, radioactive phage was purified by density gradient centrifugation. Various host strains, both RC stringent and RC relaxed were used. Results indicate that the synthesis of bacteriophage RNA is controlled by amino acids in a manner similar to that of cellular RNA. Since it is known from the work of others that infection with f2 results in the introduction into the host cell of a new template (the phage RNA) and a new (RNA-dependent) RNA polymerase, the present results are interpreted in favour of the hypothesis that mutation from RC str to RC rel most probably results in alteration of a supposed repressor of RNA synthesis. The synthesis of f2 RNA, like host RNA, is also subject to control in the energy source shift-down. It is suggested that f2 phage RNA and its RNA-dependent RNA polymerase might provide a suitable model system for in vitro studies of the control of cellular RNA synthesis.