Functional analysis of yersiniabactin transport genes of Yersinia enterocolitica

Yersinia enterocolitica O:8, biogroup (BC) is, strain WA-C carries a high-p athogenicity island (HPI) including iron-repressible genes (irp1-9, fyuA) f or biosynthesis and uptake of the siderophore yersiniabactin (Ybt). The aut hors report the functional analysis of irp6,7,8, which show 98-99 % similar ity to the corresponding genes ybtP,Q,X on the HPI of Yersinia pestis. It w as demonstrated that irp6,7 are involved in ferric (Fe)-Ybt utilization and mouse virulence of Y, enterocolitica, thus confirming corresponding result s for Y. pestis. Additionally it was shown that inactivation of the ampG-li ke gene irp8 did not affect either Fe-Ybt utilization or mouse virulence. T o determine whether irp6, irp7 and fyuA (encoding the outer-membrane Fe-Ybt /pesticin receptor FyuA) are sufficient to mediate Fe-Ybt transport/utiliza tion. these genes were transferred into Escherichia coli entD,F and into no n-pathogenic Y. enterocolitica, BG IA, strain NF-O. Surprisingly, E. coli e ntD,F but not Y. enterocolitica NF-O gained the capability to utilize exoge nous Fe-Ybt as a result of this gene transfer, although both strains expres sed functional FyuA (pesticin sensitivity). These results suggest that besi des irp6, irp7 and fyuA, additional genes are required for sufficient Fe-Yb t transport/utilization. Finally, it was shown that irp6, irp7 and fyuA but not irp8 are involved in controlling Ybt biosynthesis and fyuA gene expres sion: irp6 and/or irp7 mutation leads to upregulation whereas fyuA mutation leads to downregulation. However, fyuA-dependent control of Ybt biosynthes is could be bypassed in a fyuA mutant by ingredients of chrome azurol S (CA S) siderophore indicator agar.