NsrR Represses σ^E-Dependent Small RNAs and Interacts with RpoE via a Noncanonical Mechanism in <i>Escherichia coli</i>.

ABSTRACT: The envelope stress response in Escherichia coli is primarily governed by the sigma factor RpoE (σ^E), which activates protective genes upon membrane perturbation. Under non-stress conditions, σ^E is sequestered by its anti-sigma factor RseA. In this study, we identify an unexpected role for the nitric-oxide-sensing repressor NsrR in dampening σ^E activity and repressing σ^E-dependent small RNAs, including rybB, micA, and micL. Overexpression of nsrR represses transcription from σ^E-dependent promoters and phenocopies σ^E inactivation, resulting in filamentous morphology and growth defects. Conversely, ΔnsrR de-represses σ^E targets, with additive effects in rseA mutants-s

SUBMITTER: Aubee JI 

PROVIDER: S-EPMC12249550 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature