title: Two novel regulatory genes, fliT and fliZ, in the flagellar regulon of Salmonella.
abstract: The flagellar operons of Salmonella are divided into three classes with respect to their transcriptional hierarchy. Expression of the class 2 operons requires the class 1 gene products, FlhD and FlhC, and is increased by mutation in the flgM gene, which encodes a class 3-specific anti-sigma factor. Here we report the identification of two novel regulatory genes for class 2 transcription. Presence of the fliZ and fliT genes on multicopy plasmids enhanced and inhibited, respectively, transcription from a chromosomal class 2 promoter. Disruption of the fliZ and fliT genes on the chromosome decreased and increased, respectively, class 2 expression. These results suggest that the fliZ and fliT genes may encode positive and negative regulatory factors, respectively, for class 2 expression. Enhancement of class 2 expression by the flgM mutation was cancelled by the coexisting fliZ mutation, indicating that FliZ is essential for this enhancement.
authors.affiliation: Faculty of Applied Biological Science, Hiroshima University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kutsukake
authors.forename: T
authors.initials: T
authors.lastname: Ikebe
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D005407:Flagella / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D008565:Membrane Proteins; D018832:Molecular Chaperones; D009154:Mutation; D009876:Operon; D012475:Salmonella / Q000235:genetics*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C064971:FliA protein, Bacteria; D008565:Membrane Proteins; D018832:Molecular Chaperones; D012808:Sigma Factor; D015534:Trans-Activators; C090553:flhD protein, E coli; C071266:FlgM protein, Bacteria; C074892:fliZ protein, Bacillus subtilis; C076735:fliT protein, Bacteria