Biosynthesis of Escherichia coli RNA polymerase subunits upon release of rifampicin inhibition.

Upon release of rifampicin inhibition of Escherichia coli cells, the initiation of transcription will resume. The sequential resumption of the synthesis of proteins after release of rifampicin inhibition reflects the genetic order and size of the corresponding transcriptional units. We have used this approach to analyze whether the genes for alpha and sigma are on the same transcriptional unit as the genes for beta and beta', employing a method, which allowed us to measure the amounts of RNA polymerase subunits, alpha, beta, beta' and sigma in crude extracts. We have found that the alpha and sigma subunits are synthesized concurrently with the beta subunit in the rifampicin restart experiment, which suggests that the genes for alpha and sigma belongs to different transcriptional units.