The putative oligosaccharide translocase SypK connects biofilm formation with quorum signaling in Vibrio fischeri.
Bottom Line: We found that overexpression of sypK, which encodes a putative oligosaccharide translocase, is sufficient to activate qrr1, and, in addition, this effect appears to depend on the kinase activity of the sensor LuxQ.Finally, we found that induction of the syp locus by overexpression of sypG was sufficient to activate qrr1 levels.Together, our results show how conditions that promote biofilm formation impact the quorum-signaling network in V. fischeri, and further highlight the integrated nature of the regulatory circuits involved in complex bacterial behaviors.
Affiliation: Department of Biochemistry and Molecular Biology, Eberly College of Science, The Pennsylvania State University, University Park, Pennsylvania, 16802; Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, 53706.Show MeSH
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Mentions: We screened over 100,000 colonies and isolated ˜100 clones with elevated levels of GFP. In this study, we report our characterization of two mutants isolated from this genetic screen. Both mutants displayed qrr1 expression levels that were approximately threefold higher than wild-type cells (Fig. 2A). Sequencing of the transposon insertion site in each mutant revealed an insertion in either VF_A1028 (sypI) or VF_A1029 (sypJ) (Fig. 2B). To determine whether the phenotype of elevated qrr1 expression was linked to the transposon, we reintroduced the sypI transposon insertion into ES114 by transformation. The resulting strain, DRO222 (designated sypI::Tn5 [NT]), showed qrr1 expression levels comparable to the original transposon insertion mutant (sypI::Tn5), indicating that the transposon insertion in sypI is linked to elevated qrr1 expression (Fig. 2A). Hereafter, the sypI::Tn5 [NT] mutant is termed the sypI mutant.
Affiliation: Department of Biochemistry and Molecular Biology, Eberly College of Science, The Pennsylvania State University, University Park, Pennsylvania, 16802; Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, 53706.