Transcription-termination factor Rho from Bacills subtilis.

A protein has been isolated from Bacillus subtilis which has functions similar to that of transcription termination factor rho (rho) from Escherichia coli. The apparent molecular weight of the B. subtilis rho factor is about 80000-95000 as estimated by a non-denaturing polyacrylamide gel electrophoresis method. It contains two subunits with a molecular weight of 47000 as determined by sodium dodecylsulfate/polyacrylamide gel electrophoresis. The rho factor shows poly(C)-dependent beta-gamma ATPase activity and depresses the activity of RNA synthesis from B. subtilis phage rho 29 DNA template with purified B. subtilis RNA polymerase holoenzyme. The specific activity of the poly(C)-dependent ATPase of the B. subtilis rho factor was significantly less than that of the E. coli rho factor. In the presence of rho factor fewer RNA transcripts were produced overall from the rho 29 template and smaller RNA transcripts with discrete sizes were made. These results suggest that the B. subtilis rho factor can catalyze transcription termination at specific sites on rho 29 phage DNA in vitro.