1. Sensing structural intermediates in bacterial flagellar assembly by export of a negative regulator.
- Author
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Hughes KT, Gillen KL, Semon MJ, and Karlinsey JE
- Subjects
- Bacterial Proteins genetics, Flagella metabolism, Gene Expression Regulation, Bacterial, Genes, Bacterial, Genes, Regulator, Models, Biological, Morphogenesis, Recombinant Fusion Proteins metabolism, Salmonella typhimurium genetics, Salmonella typhimurium growth & development, Salmonella typhimurium metabolism, Sigma Factor genetics, Sigma Factor metabolism, Bacterial Proteins metabolism, Flagella ultrastructure, Flagellin genetics, Salmonella typhimurium ultrastructure, Transcription, Genetic
- Abstract
The ability of a regulatory protein to sense the integrity of the bacterial flagellar structure was investigated. In response to a defective hook-basal body complex, the anti-sigma 28 FlgM protein inhibits flagellin transcription. In cells with a functional hook-basal body complex, the flagellin genes are transcribed normally and the FlgM protein is expelled into the growth medium. In strains with a defective hook-basal body structure, FlgM is absent from the media. The presence of flagellin protein in the media is substantially reduced in strains carrying a FlgM-LacZ protein fusion, suggesting that the fusion is blocking the flagellar export apparatus. These results suggest that the FlgM protein assesses the integrity of the flagellar hook-basal body complex by itself being a substrate for export by the flagellar-specific export apparatus.
- Published
- 1993
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