EςE RNA polymerase transcribes a regulon of folding factors for the bacterial envelope and is induced by physical and chemical stresses. The RseA anti-sigma factor inhibits the activity of EςE RNA polymerase. It is shown here that the N-terminal portion of ςE, residues 1–153, binds core RNA polymerase. RseA interacts with residues 154–191 of ςE, a site that is homologous to region 4, the sigma factor binding site for promoter DNA. Mutations that reduce transcription of EςE RNA polymerase map to ςE residues 178, 181, and 183. Variant ςEproteins with amino acid substitutions at residues 178, 181, or 183 do not associate with RseA. A regulatory mechanism is proposed whereby RseA binds to a C-terminal peptide of ςE and inhibits the transcription of EςE RNA polymerase by blocking promoter recognition.

The RseA anti-sigma factor inhibits EE RNA polymerase transcription by binding to a C-terminal peptide of E and blocking promoter recognition.

Interaction of the Conserved Region 4.2 of ςE with the RseA Anti-sigma Factor*

Key Takeaway: The RseA anti-sigma factor inhibits EE RNA polymerase transcription by binding to a C-terminal peptide of E and blocking promoter recognition.