Disease relevance of prgH

• Previously, the PhoP-repressed locus prgH was identified as important for signalling epithelial cells to endocytose Salmonella typhimurium [1].

High impact information on prgH

• Previously, prgH and prgK were shown to be required for formation of the supramolecular type III secretion needle complex (NC) [Kubori, T., et al. (1998) Science 280, 602-605] [2].
• In order to understand how HilA controls the transcription of SPI-1 genes, we have analysed the invF and prgH promoters [3].
• SirA of Salmonella typhimurium is known to regulate the hilA and prgH genes within Salmonella pathogenicity island 1 (SPI1) [4].
• Here we describe four genes (SspB, sspC, sspD, and sspA), located between spaT and prgH, which encode proteins of 63, 42, 36, and 87 kDa, respectively [5].
• At least one prg locus, prgH, is required for full S. typhimurium mouse virulence [6].

Biological context of prgH

• The invasion defect of PrgH but not that of PhoPc mutant bacteria was complemented by plasmids containing prgH (hil) DNA [7].
• One prg locus, prgH, was demonstrated to contribute to mouse virulence by both the oral and the intraperitoneal routes. prgH was located at 59 min on the Salmonella chromosome, a region where other genes essential to invasion of epithelial cells are clustered [7].
• The prgH locus was highly linked to one invasion locus, hil (C.A. Lee, B.D. Jones, and S. Falkow, Proc. Natl. Acad. Sci. USA 89:1847-1851, 1992), although transcription of prgH was opposite that of the Tn5B50-encoded promoters that result in a hyperinvasive or hil phenotype [7].

Anatomical context of prgH

• Previously, growth in the presence of bile was shown to repress the transcription of prgH, a locus encoding components of the Salmonella pathogenicity island I (SPI-1) type III secretion system (TTSS) necessary for eukaryotic cell invasion [8].
• Increased levels of pmrH, phoP, and prgH transcription but not ssaB were observed in bacteria isolated from the lumen of the distal ileum [9].

Other interactions of prgH

• Here, we present experiments indicating that orgA expression is driven by the prgH promoter [10].
• Invasion-deficient S. typhimurium strains carrying mutations in components of SPI1 (invA, invG, sspC, and prgH) exhibited filamentous appendages similar to those on wild-type S. typhimurium when adhering to epithelial cells, demonstrating that formation of these appendages is not itself sufficient to trigger bacterial invasion [11].

Analytical, diagnostic and therapeutic context of prgH

• In addition, using reverse transcriptase PCR analysis, we have found that this polycistronic message extends downstream of prgH to include a total of 10 genes [10].

References