Deoxyribonucleic acid-dependent ribonucleic acid synthesis in Escherichia coli infected with bacteriophage T2

Following infection of Escherichia coli by the bacteriophage T2, ribonucleic acid polymerase activity in unfractionated extracts is reduced to approximately twenty per cent of the activity in unfractionated extracts of uninfected cells. The residual enzyme activity is sensitive to deoxyribonuclease, to ribonuclease and to actinomycin D. RNA polymerase can be purified from extracts of T2-infected cells with a yield of more than 200%. The purified enzyme has properties similar to the enzyme purified from uninfected cells. Deoxyribonucleic acid isolated from T2-infected cells is a mixture of high molecular weight bacterial and viral DNA. Both components of this mixture are active as templates for RNA polymerase in vitro, although only the viral DNA is a template in vivo. As reported by Skold & Buchanan (1964), material which inhibits purified RNA polymerase in vitro appears in cell extracts following T2 infection. The inhibitory material is destroyed by acid treatment and reduced in amount by digestion with alkali. Incubation overnight at 37°C and heating at 100°C increase the amount of inhibitory material. In control experiments with uninfected E. coli, inhibitory material is not present in the initial extract or after treatment with acid. Treatment with alkali, incubation overnight at 37°C or heating at 100°C result in levels of inhibitory material similar to that in extracts of infected cells subjected to the same treatment.