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PhoP-induced genes within Salmonella pathogenicity island 1.
J Bacteriol. 2006 Oct; 188(19):6889-98.JB

Abstract

The invasive pathogen Salmonella enterica has evolved a sophisticated device that allows it to enter nonphagocytic host cells. This process requires the expression of Salmonella pathogenicity island 1 (SPI-1), which encodes a specialized type III protein secretion system (TTSS). This TTSS delivers a set of effectors that produce a marked rearrangement of the host cytoskeleton, generating a profuse membrane ruffling at the site of interaction, driving bacterial entry. It has been shown that the PhoP/PhoQ two-component system represses the expression of the SPI-1 machinery by down-regulating the transcription of its master regulator, HilA. In this work, we reveal the presence of a PhoP-activated operon within SPI-1. This operon is composed of the orgB and orgC genes, which encode a protein that interacts with the InvC ATPase and a putative effector protein of the TTSS, respectively. Under PhoP-inducing conditions, expression of this operon is directly activated by the phosphorylated form of the response regulator, which recognizes a PhoP box located at the -35 region relative to the transcription start site. Additionally, under invasion-inducing conditions, orgBC expression is driven both by the prgH promoter, induced by the SPI-1 master regulator HilA, and by the directly controlled PhoP/PhoQ promoter. Together, these results indicate that in contrast to the rest of the genes encompassed in the SPI-1 locus, orgBC is expressed during and after Salmonella entry into its host cell, and they suggest a role for the products of this operon after host cell internalization.

Authors+Show Affiliations

Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas (UNR), Suipacha 531, S2002LRK Rosario, Argentina.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16980492

Citation

Aguirre, Andrés, et al. "PhoP-induced Genes Within Salmonella Pathogenicity Island 1." Journal of Bacteriology, vol. 188, no. 19, 2006, pp. 6889-98.
Aguirre A, Cabeza ML, Spinelli SV, et al. PhoP-induced genes within Salmonella pathogenicity island 1. J Bacteriol. 2006;188(19):6889-98.
Aguirre, A., Cabeza, M. L., Spinelli, S. V., McClelland, M., García Véscovi, E., & Soncini, F. C. (2006). PhoP-induced genes within Salmonella pathogenicity island 1. Journal of Bacteriology, 188(19), 6889-98.
Aguirre A, et al. PhoP-induced Genes Within Salmonella Pathogenicity Island 1. J Bacteriol. 2006;188(19):6889-98. PubMed PMID: 16980492.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - PhoP-induced genes within Salmonella pathogenicity island 1. AU - Aguirre,Andrés, AU - Cabeza,María Laura, AU - Spinelli,Silvana V, AU - McClelland,Michael, AU - García Véscovi,Eleonora, AU - Soncini,Fernando C, PY - 2006/9/19/pubmed PY - 2006/10/17/medline PY - 2006/9/19/entrez SP - 6889 EP - 98 JF - Journal of bacteriology JO - J Bacteriol VL - 188 IS - 19 N2 - The invasive pathogen Salmonella enterica has evolved a sophisticated device that allows it to enter nonphagocytic host cells. This process requires the expression of Salmonella pathogenicity island 1 (SPI-1), which encodes a specialized type III protein secretion system (TTSS). This TTSS delivers a set of effectors that produce a marked rearrangement of the host cytoskeleton, generating a profuse membrane ruffling at the site of interaction, driving bacterial entry. It has been shown that the PhoP/PhoQ two-component system represses the expression of the SPI-1 machinery by down-regulating the transcription of its master regulator, HilA. In this work, we reveal the presence of a PhoP-activated operon within SPI-1. This operon is composed of the orgB and orgC genes, which encode a protein that interacts with the InvC ATPase and a putative effector protein of the TTSS, respectively. Under PhoP-inducing conditions, expression of this operon is directly activated by the phosphorylated form of the response regulator, which recognizes a PhoP box located at the -35 region relative to the transcription start site. Additionally, under invasion-inducing conditions, orgBC expression is driven both by the prgH promoter, induced by the SPI-1 master regulator HilA, and by the directly controlled PhoP/PhoQ promoter. Together, these results indicate that in contrast to the rest of the genes encompassed in the SPI-1 locus, orgBC is expressed during and after Salmonella entry into its host cell, and they suggest a role for the products of this operon after host cell internalization. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/16980492/PhoP_induced_genes_within_Salmonella_pathogenicity_island_1_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=16980492 DB - PRIME DP - Unbound Medicine ER -