Replication of RNA bacteriophage R23. I. Quantitative aspects of phage RNA and protein synthesis

Infection of Escherichia coli by R23, a newly isolated strain of RNA bacteriophage, has been found markedly to suppress synthesis of bacterial RNA. Approximately 60% of total RNA synthesized after infection was encapsulated in progeny phage particles. In contrast, after infection with the RNA phages f2 or Qβ, only 25 to 30% of newly synthesized RNA was phage RNA. Thirty to 40% of the RNA synthesized after B23 infection was characterized as a second form of phage-specific RNA by its resistance to RNase. Synthesis of bacterial proteins was also markedly inhibited after infection by R23 and ultimately replaced by phage-directed protein synthesis. B23 "early" protein synthesis, detected as phage RNA polymerase activity, was evident five to ten minutes after infection and increased until 20 to 30 minutes. In contrast, in the normally infected cell, synthesis of coat protein was predominant at a later time, beginning 30 to 45 minutes after infection and reaching a maximum between 45 and 75 minutes of infection, when coat protein constituted almost all of the newly synthesized protein. Coat protein synthesis was not detectable in the absence of RNA synthesis, whereas phage RNA polymerase induction required little or no RNA synthesis.