Two novel regulatory genes, fliT and fliZ, in the flagellar regulon of Salmonella.
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.
Kutsukake
K
K
Faculty of Applied Biological Science, Hiroshima University, Japan.
Ikebe
T
T
Yamamoto
S
S
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
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