title: RyhB, an iron-responsive small RNA molecule, regulates Shigella dysenteriae virulence.
abstract: Regulation of bacterial gene expression by small RNA (sRNA) molecules is an increasingly recognized phenomenon but one that is not yet fully understood. We show that the sRNA RyhB suppresses several virulence-associated phenotypes of Shigella dysenteriae, a causative agent of bacillary dysentery in humans. The virulence genes repressed by S. dysenteriae RyhB include those encoding the type III secretion apparatus, its secreted effectors, and specific chaperones. Suppression of Shigella virulence occurs via RyhB-dependent repression of the transcriptional activator VirB, leading to reduced expression of genes within the VirB regulon. Efficient repression of virB is mediated by a single-stranded region of RyhB that is distinct from the region required for repression of Shigella sodB. Regulation of virB by RyhB implicates iron as an environmental factor contributing to the complex regulation of Shigella virulence determinants.
authors: University of Texas at Austin, Section of Molecular Genetics and Microbiology, 1 University Station A5000, Austin, TX 78712, USA.
authors: Erin R
authors: ER
authors: Murphy
authors: Shelley M
authors: SM
authors: Payne
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002478:Cells, Cultured; D004405:Dysentery, Bacillary; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008138:Loop of Henle / Q000382:microbiology; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012762:Shigella dysenteriae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D015534:Trans-Activators; D007501:Iron