Bacteriophage SPO1 DNA- and RNA-directed protein synthesis in vitro: the effect of TF1, a template-selective transcription inhibitor.

Transcription factor one (TF1), a protein synthesized after infection of B. subtilis by phage SPO1, is a specific inhibitor of SPO1 in vitro transcription. In this paper, we investigate the effect of TF1 on SPO1-specific in vitro protein synthesis, using SPO1 DNA or messenger RNA as templates. Protein syhthesis is measured by incorporation of radioactive amino acids into acid insoluble form, synthesis of a phage-specific enzymatic activity, and analysis of radioactive polypeptides by acrylamide gel electrophoresis. TF1 is shown to inhibit the DNA-dependent synthesis of all SPO1 proteins which can be made in vitro, but to have no specific effect on RNA-dependent protein synthesis in vitro.