Temperature‐dependent regulation of Yersinia enterocolitica Class III flagellar genes

Abstract

Temperature is a key environmental cue for Yersinia enterocolitica as well as for the two other closely related pathogens, Yersinia pestis and Yersinia pseudotuberculosis. Between the range of 30 degrees C and 37 degrees C, Y. enterocolitica phase-varies between motility and plasmid-encoded virulence gene expression. To determine how temperature regulates Y. enterocolitica motility, we have been dissecting the flagellar regulatory hierarchy to determine at which level motility is blocked by elevated temperature (37 degrees C). Here we report the cloning, DNA sequences, and regulation of the two main regulators of Class III flagellar genes, fliA (sigma F) and flgM (anti-sigma F), and a third gene, flgN, which we show is required for filament assembly. Identification of the Y. enterocolitica fliA and flgM genes was accomplished by functional complementation of both S. typhimurium and Y. enterocolitica mutations and by DNA sequence analysis. The Y. enterocolitica fliA gene, encoding the flagellar-specific sigma-factor, sigma F, maps immediately downstream of the three flagellin structural genes. The flgM and flgN genes, encoding anti-sigma F and a gene product required for filament assembly, respectively, map downstream of the invasin (inv) gene but are transcribed in the opposite (convergent) direction. By using Northern blot analyses we show that transcription of both fliA and flgM is immediately arrested when cells are exposed to 37 degrees C, coincident with the timing of virulence gene induction. Unlike S. typhimurium flgM mutants, Y. enterocolitica flgM mutants are fully virulent.

A new pathway for the secretion of virulence factors by bacteria: The flagellar export apparatus functions as a protein-secretion system

“…Fop production first was examined in a strain carrying a mutation in fliA that encodes 28 and is necessary for flagellar class III gene transcription (10). The fliA mutant did not produce flagellin, as was shown previously (10), and it also did not secrete the Fops (Fig.…”

“…All Y. enterocolitica strains used in this study were derived from JB580v [⌬yenR (R Ϫ M previously (7,9,10) . Escherichia coli S17-1(pir) was used to conjugally transfer plasmids to Y. enterocolitica (11).…”

A motile but non‐swarming mutant of Proteus mirabilis lacks FlgN, a facilitator of flagella filament assembly

“…2) Minamino et al, 1994). The orf immediately downstream of P. mirabilis flgMN appears to be unique; it is not similar to genes identified in Escherichia coli or S. typhimurium or to Y. pseudotubercolosis invA (Isberg et al, 1987), which is located in an otherwise identical linkage at this locus (Kapatral et al, 1996). We call it floA, for flagella locus orf.…”

Contribution of FliC to Epithelial Cell Invasion by Enterohemorrhagic Escherichia coli O113:H21

“…Previous work has shown that FliC is more highly expressed at temperatures below 37°C in the invasive pathogens Yersinia enterocolitica and Listeria monocytogenes (3,9,18). We therefore examined FliC H21 expression by wild-type STEC O113:H21 strain EH41 at two different growth temperatures.…”