Figure 1. The YfiBNR system of Pseudomonas aeruginosa.

A) Organization of the yfiBNR operon. Transposon insertions in yfiR inducing the SCV phenotype are marked with grey triangles. B) Domain organization of the Yfi proteins. S.S. (YfiR) denotes an export signal sequence, vertical grey bars (YfiN) represent transmembrane helices, and OMP (YfiB) denotes the OmpA/Pal-like protein fold. The HAMP and GGDEF domains of YfiN are labeled. C) Colony morphology of the yfiR::Tn mutants grown on LB Congo-red agar. The morphology of the non-polar yfiR deletion is indistinguishable from the yfiR::Tn strains. D) Over-expression of the phosphodiesterase PA5295 abolishes surface attachment and SCV morphology of the ΔyfiR mutant. PA5295-AAL denotes an active site mutant of PA5295. Attachment levels are expressed relative to PA01. The graph shows a representative of two independent experiments.