| Summary: | <p>Abstract</p> <p>Background</p> <p>In order to identify new virulence determinants in <it>Y. pseudotuberculosis </it>a comparison between its genome and that of <it>Yersinia pestis </it>was undertaken. This reveals dozens of pseudogenes in <it>Y. pestis</it>, which are still putatively functional in <it>Y. pseudotuberculosis </it>and may be important in the enteric lifestyle. One such gene, <it>YPTB1572 </it>in the <it>Y. pseudotuberculosis </it>IP32953 genome sequence, encodes a protein with similarity to invasin, a classic adhesion/invasion protein, and to intimin, the attaching and effacing protein from enteropathogenic (EPEC) and enterohaemorraghic (EHEC) <it>Escherichia coli</it>.</p> <p>Results</p> <p>We termed YPTB1572 Ifp (Intimin family protein) and show that it is able to bind directly to human HEp-2 epithelial cells. Cysteine and tryptophan residues in the C-terminal region of intimin that are essential for function in EPEC and EHEC are conserved in Ifp. Protein binding occurred at distinct foci on the HEp-2 cell surface and can be disrupted by mutation of a single cysteine residue at the C-terminus of the protein. Temporal expression analysis using <it>lux </it>reporter constructs revealed that <it>ifp </it>is expressed at late log phase at 37°C in contrast to invasin, suggesting that Ifp is a late stage adhesin. An <it>ifp </it>defined mutant showed a reduction in adhesion to HEp-2 cells and was attenuated in the <it>Galleria mellonella </it>infection model.</p> <p>Conclusion</p> <p>A new <it>Y. pseudotuberculosis </it>adhesin has been identified and characterised. This Ifp is a new member in the family of invasin/intimin outer membrane adhesins.</p>
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