Send to

Choose Destination
See comment in PubMed Commons below
Microbiology. 2009 Jun;155(Pt 6):1890-900. doi: 10.1099/mic.0.026294-0. Epub 2009 Apr 21.

Functional characterization of FlgM in the regulation of flagellar synthesis and motility in Yersinia pseudotuberculosis.

Author information

Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, China.


We describe here the functional characterization of the flgM gene in Yersinia pseudotuberculosis. Direct interaction of FlgM with the alternative sigma factor sigma(28) (FliA) was first confirmed. A conserved region in the C-terminus of FlgM was found which included the sigma(28) binding domain. By site-directed mutagenesis, bacterial two-hybrid analysis and Western blotting, the primary FlgM binding sites with sigma(28) were shown to be Ile85, Ala86 and Leu89. A role for FlgM in swimming motility was demonstrated by inactivation of flgM and subsequent complementation in trans. Transcriptional fusion analyses showed differential gene expression of flhDC, fliA, flgM and fliC in the fliA and flgM mutants compared with the wild-type. flhDC expression was not influenced by sigma(28) or FlgM while fliA expression was abolished in the fliA mutant and considerably reduced in the flgM mutant when compared to the wild-type, indicating that both FliA and FlgM can activate fliA transcription. Conversely, flgM transcription was higher in the fliA mutant when compared to the wild-type, suggesting that flgM transcription was repressed by sigma(28). Interestingly, fliC expression was markedly increased in the flgM mutant, suggesting a negative regulatory role for FlgM in fliC expression. The transcription of other sigma-dependent genes (cheW, flgD, flaA, csrA and fliZ) was also examined in fliA and flgM mutant backgrounds and this revealed that other sigma-factors apart from sigma(28) may be involved in flagellar biogenesis in Y. pseudotuberculosis. Taking together the motility phenotypes and effects of flgM mutation on the regulation of these key motility genes, we propose that the mechanisms regulating flagellar biogenesis in Y. pseudotuberculosis may differ from those described for other bacteria.

[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Ingenta plc
    Loading ...
    Support Center