Bacteriophage SPO1 DNA- and RNA-directed protein synthesis in vitro: comparison with in vivo control.

A cell free protein synthesizing system, derived from E. coli, is shown to be a quantitiative assay system for messenger RNA extracted from B. subtilis infected with bacteriophage SPO1. DNA-directed protein synthesis in this system is shown to be limited mostly to those proteins whose messages are contained in early RNA. A phage induced enzyme, dCMP deaminase, is shown to be dependent on appearance of a class mRNA made in vivo in response to new initiations of transcription dependent on prior synthesis of phage induced protein. Control of the enzyme synthesized in the cell free system is contrasted with in vivo control, and an estimate of "read-through" by RNA polymerase in vitro is presented.