Genotoxic, Metabolic, and Oxidative Stresses Regulate the RNA Repair Operon of Salmonella enterica Serovar Typhimurium.

The σ regulon in serovar Typhimurium includes a predicted RNA repair operon encoding homologs of the metazoan Ro60 protein (Rsr), Y RNAs (YrlBA), RNA ligase (RtcB), and RNA 3'-phosphate cyclase (RtcA). Transcription from σ-dependent promoters requires that a cognate bacterial enhancer binding protein (bEBP) be activated by a specific environmental or cellular signal; the cognate bEBP for the σ-dependent promoter of the operon is RtcR. To identify conditions that generate the signal for RtcR activation in Typhimurium, transcription of the RNA repair operon was assayed under multiple stress conditions that result in nucleic acid damage.