A gene, yaeQ, that suppresses reduced operon expression caused by mutations in the transcription elongation gene rfaH in Escherichia coli and Salmonella typhimurium

Abstract

RfaH is a specialised transcription elongation protein. We isolated from a Salmonella typhimurium rfaH suppressor strain a gene that complements in trans the attenuated transcription of the hlyCABD hemolysin operon caused by an rfaH mutation. The gene is homologous to the uncharacterised Escherichia coli gene yaeQ. YaeQ did not increase hlyCABD-encoded hemolysin activity in the RfaH⁺ wild type, nor did it increase the level of RfaH protein. YaeQ also complements a rfaH::Tn5 null mutation, indicating that it compensates for loss of RfaH function without interaction between the two proteins.