Regulon controlled by the GppX hybrid two component system in Porphyromonas gingivalis.
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ABSTRACT: The periodontal pathogen Porphyromonas gingivalis experiences a number of environmental conditions in the oral cavity, and must monitor and respond to a variety of environmental cues. However, the organism possesses only five full two-component systems, one of which is the hybrid system GppX. To investigate the regulon controlled by GppX we performed RNA-Seq on a ?GppX mutant. Fifty-three genes were upregulated and 37 genes were downregulated in the ?GppX mutant. Pathway analyses revealed no systemic function for GppX under nutrient-replete conditions; however, over 40% of the differentially abundant genes were annotated as encoding hypothetical proteins indicating a novel role for GppX. Abundance of small RNA was, in general, not affected by the absence of GppX. To further define the role of GppX with respect to regulation of a hypothetical protein observed with the greatest significant relative abundance change relative to a wild-type control, PGN_0151, we constructed a series of strains in which the ?gppX mutation was complemented with a GppX protein containing specific domain and phosphotransfer mutations. The transmembrane domains, the DNA-binding domain and the phosphotransfer residues were all required for regulation of PGN_0151. In addition, binding of GppX to the PGN_0151 promoter regions was confirmed by an electrophoretic mobility shift assay. Both the ?GppX mutant and a ?PGN_0151 mutant were deficient in monospecies biofilm formation, suggesting a role for the GppX-PGN_0151 regulon in colonization and survival of the organism.
SUBMITTER: Hirano T
PROVIDER: S-EPMC3543493 | biostudies-literature | 2013 Feb
REPOSITORIES: biostudies-literature
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