1887

Abstract

The type III secretion system (TTSS) encoded by pathogenicity island 2 (SPI-2) is expressed after bacterial entry into host cells. The SPI-2 TTSS secretes the translocon components SseBCD, which translocate across the vacuolar membrane a number of effector proteins whose action is required for intracellular bacterial replication. Several of these effectors, including SifA and SifB, are encoded outside SPI-2. The two-component regulatory system SsrA–SsrB, encoded within SPI-2, controls the expression of components of the SPI-2 TTSS apparatus as well as its translocated effectors. The expression of SsrA–B is in turn regulated by the OmpR–EnvZ two-component system, by direct binding of OmpR to the promoter. Several environmental signals have been shown to induce expression of genes regulated by the SsrA–B or OmpR–EnvZ systems. In this work, immunoblotting and flow cytometry were used to analyse the roles of SsrA–B and OmpR–EnvZ in coupling different environmental signals to changes in expression of a SPI-2 TTSS translocon component (SseB) and two effector genes ( and ). Using single and double mutant strains the relative contribution of each regulatory system to the response generated by low osmolarity, acidic pH or the absence of Ca was determined. SsrA–B was found to be essential for the induction of SPI-2 gene expression in response to each of these individual signals. OmpR–EnvZ was found to play a minor role in sensing these signals and to require a functional SsrA–B system to mediate their effect on SPI-2 TTSS gene expression.

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2003-09-01
2020-07-16
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References

  1. Bajaj V., Lucas R. L., Hwang C., Lee C. A.. 1996; Co-ordinate regulation of Salmonella typhimurium invasion genes by environmental and regulatory factors is mediated by control of hilA expression. Mol Microbiol22:703–714
    [Google Scholar]
  2. Beier D., Schwarz B., Fuchs T. M., Gross R.. 1995; In vivo characterization of the unorthodox BvgS two-component sensor protein of Bordetella pertussis . J Mol Biol248:596–610
    [Google Scholar]
  3. Beuzón C. R., Banks G., Deiwick J., Hensel M., Holden D. W.. 1999; pH-dependent secretion of SseB, a product of the SPI-2 type III secretion system of Salmonella typhimurium . Mol Microbiol33:806–816
    [Google Scholar]
  4. Beuzón C. R., Meresse S., Unsworth K. E., Ruiz-Albert J., Garvis S., Waterman S. R., Ryder T. A., Boucrot E., Holden D. W.. 2000; Salmonella maintains the integrity of its intracellular vacuole through the action of SifA [erratum appears in EMBO J . 19, 4191]. EMBO J19:3235–3249
    [Google Scholar]
  5. Beuzón C. R., Unsworth K. E., Holden D. W.. 2001; In vivo genetic analysis indicates that PhoP-PhoQ and the Salmonella pathogenicity island 2 type III secretion system contribute independently to Salmonella enterica serovar Typhimurium virulence. Infect Immun69:7254–7261
    [Google Scholar]
  6. Brumell J. H., Rosenberger C. M., Gotto G. T., Marcus S. L., Finlay B. B.. 2001; SifA permits survival and replication of Salmonella typhimurium in murine macrophages. Cell Microbiol3:75–84
    [Google Scholar]
  7. Brumell J. H., Kujat-Choy S., Brown N. F., Vallance B. A., Knodler L. A., Finlay B. B.. 2003; SopD2 is a novel Type III secreted effector of Salmonella typhimurium that targets late endocytic compartments upon delivery into host cells. Traffic4:36–48
    [Google Scholar]
  8. Buchmeier N. A., Libby S. J.. 1997; Dynamics of growth and death within a Salmonella typhimurium population during infection of macrophages. Can J Microbiol43:29–34
    [Google Scholar]
  9. Chatfield S. N., Dorman C. J., Hayward C., Dougan G.. 1991; Role of ompR -dependent genes in Salmonella typhimurium virulence: mutants deficient in both ompC and ompF are attenuated in vivo . Infect Immun59:449–452
    [Google Scholar]
  10. Christensen K. A., Myers J. T., Swanson J. A.. 2002; pH-dependent regulation of lysosomal calcium in macrophages. J Cell Sci115:599–607
    [Google Scholar]
  11. Cirillo D. M., Valdivia R. H., Monack D. M., Falkow S.. 1998; Macrophage-dependent induction of the Salmonella pathogenicity island 2 type III secretion system and its role in intracellular survival. Mol Microbiol30:175–188
    [Google Scholar]
  12. Cornelis G. R., Van Gijsegem F.. 2000; Assembly and function of type III secretory systems. Annu Rev Microbiol54:735–774
    [Google Scholar]
  13. Deiwick J., Hensel M.. 1999; Regulation of virulence genes by environmental signals in Salmonella typhimurium . Electrophoresis20:813–817
    [Google Scholar]
  14. Deiwick J., Nikolaus T., Erdogan S., Hensel M.. 1999; Environmental regulation of Salmonella pathogenicity island 2 gene expression. Mol Microbiol31:1759–1773
    [Google Scholar]
  15. Dorman C. J., Chatfield S., Higgins C. F., Hayward C., Dougan G.. 1989; Characterization of porin and ompR mutants of a virulent strain of Salmonella typhimurium : ompR mutants are attenuated in vivo . Infect Immun57:2136–2140
    [Google Scholar]
  16. Fields P. I., Swanson R. V., Haidaris C. G., Heffron F.. 1986; Mutants of Salmonella typhimurium that cannot survive within the macrophage are avirulent. Proc Natl Acad Sci U S A83:5189–5193
    [Google Scholar]
  17. Freeman J. A., Ohl M. E., Miller S. I.. 2003; The Salmonella enterica serovar typhimurium translocated effectors SseJ and SifB are targeted to the Salmonella -containing vacuole. Infect Immun71:418–427
    [Google Scholar]
  18. Groisman E. A.. 2001; The pleiotropic two-component regulatory system PhoP-PhoQ. J Bacteriol183:1835–1842
    [Google Scholar]
  19. Hensel M., Shea J. E., Gleeson C., Jones M. D., Dalton E., Holden D. W.. 1995; Simultaneous identification of bacterial virulence genes by negative selection. Science269:400–403
    [Google Scholar]
  20. Hensel M., Shea J. E., Waterman S. R.. 7 other authors 1998; Genes encoding putative effector proteins of the type III secretion system of Salmonella pathogenicity island 2 are required for bacterial virulence and proliferation in macrophages. Mol Microbiol30:163–174
    [Google Scholar]
  21. Hersh D., Monack D. M., Smith M. R., Ghori N., Falkow S., Zychlinsky A.. 1999; The Salmonella invasin SipB induces macrophage apoptosis by binding to caspase-1. Proc Natl Acad Sci U S A96:2396–2401
    [Google Scholar]
  22. Heyde M., Portalier R.. 1987; Regulation of major outer membrane porin proteins of Escherichia coli K12 by pH. Mol Gen Genet208:511–517
    [Google Scholar]
  23. Hmiel S. P., Snavely M. D., Miller C. G., Maguire M. E.. 1986; Magnesium transport in Salmonella typhimurium : characterization of magnesium influx and cloning of a transport gene. J Bacteriol168:1444–1450
    [Google Scholar]
  24. Hueck C. J.. 1998; Type III protein secretion systems in bacterial pathogens of animals and plants. Microbiol Mol Biol Rev62:379–433
    [Google Scholar]
  25. Humphreys S., Stevenson A., Bacon A., Weinhardt A. B., Roberts M.. 1999; The alternative sigma factor, sigmaE, is critically important for the virulence of Salmonella typhimurium . Infect Immun67:1560–1568
    [Google Scholar]
  26. Jung K., Hamann K., Revermann A.. 2001; K+ stimulates specifically the autokinase activity of purified and reconstituted EnvZ of Escherichia coli . J Biol Chem276:40896–40902
    [Google Scholar]
  27. Kempf B., Bremer E.. 1998; Uptake and synthesis of compatible solutes as microbial stress responses to high-osmolality environments. Arch Microbiol170:319–330
    [Google Scholar]
  28. Knodler L. A., Celli J., Hardt W. D., Vallance B. A., Yip C., Finlay B. B.. 2002; Salmonella effectors within a single pathogenicity island are differentially expressed and translocated by separate type III secretion systems. Mol Microbiol43:1089–1103
    [Google Scholar]
  29. Kyhse-Andersen J.. 1984; Electroblotting of multiple gels: a simple apparatus without buffer tank for rapid transfer of proteins from polyacrylamide to nitrocellulose. J Biochem Biophys Methods10:203–209
    [Google Scholar]
  30. Laemmli U. K.. 1970; Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature227:680–685
    [Google Scholar]
  31. Lee A. K., Detweiler C. S., Falkow S.. 2000; OmpR regulates the two-component system ssrA-ssrB in Salmonella pathogenicity island 2. J Bacteriol182:771–781
    [Google Scholar]
  32. Libby S. J., Goebel W., Ludwig A., Buchmeier N., Bowe F., Fang F. C., Guiney D. G., Songer J. G., Heffron F.. 1994; A cytolysin encoded by Salmonella is required for survival within macrophages. Proc Natl Acad Sci U S A91:489–493
    [Google Scholar]
  33. Miao E. A., Miller S. I.. 2000; A conserved amino acid sequence directing intracellular type III secretion by Salmonella typhimurium . Proc Natl Acad Sci U S A97:7539–7544
    [Google Scholar]
  34. Miao E. A., Freeman J. A., Miller S. I.. 2002; Transcription of the SsrAB regulon is repressed by alkaline pH and is independent of PhoPQ and magnesium concentration. J Bacteriol184:1493–1497
    [Google Scholar]
  35. Miller J. F., Johnson S. A., Black W. J., Beattie D. T., Mekalanos J. J., Falkow S.. 1992; Constitutive sensory transduction mutations in the Bordetella pertussis bvgS gene. J Bacteriol174:970–979
    [Google Scholar]
  36. Nikolaus T., Deiwick J., Rappl C., Freeman J. A., Schroder W., Miller S. I., Hensel M.. 2001; SseBCD proteins are secreted by the type III secretion system of Salmonella pathogenicity island 2 and function as a translocon. J Bacteriol183:6036–6045
    [Google Scholar]
  37. O'Neal C. R., Gabriel W. M., Turk A. K., Libby S. J., Fang F. C., Spector M. P.. 1994; RpoS is necessary for both the positive and negative regulation of starvation survival genes during phosphate, carbon, and nitrogen starvation in Salmonella typhimurium . J Bacteriol176:4610–4616
    [Google Scholar]
  38. Ochman H., Soncini F. C., Solomon F., Groisman E. A.. 1996; Identification of a pathogenicity island required for Salmonella survival in host cells. Proc Natl Acad Sci U S A93:7800–7804
    [Google Scholar]
  39. Rathman M., Sjaastad M. D., Falkow S.. 1996; Acidification of phagosomes containing Salmonella typhimurium in murine macrophages. Infect Immun64:2765–2773
    [Google Scholar]
  40. Reeves E. P., Lu H., Jacobs H. L.. 7 other authors 2002; Killing activity of neutrophils is mediated through activation of proteases by K+ flux. Nature416:291–297
    [Google Scholar]
  41. Ruiz-Albert J., Yu X. J., Beuzón C. R., Blakey A. N., Galyov E. E., Holden D. W.. 2002; Complementary activities of SseJ and SifA regulate dynamics of the Salmonella typhimurium vacuolar membrane. Mol Microbiol44:645–661
    [Google Scholar]
  42. Ruiz-Albert J., Mundy R., Yu X. J., Beuzón C. R., Holden D. W.. 2003; SseA is a chaperone for the SseB and SseD translocon components of the Salmonella pathogenicity-island-2-encoded type III secretion system. Microbiology149:1103–1111
    [Google Scholar]
  43. Shea J. E., Hensel M., Gleeson C., Holden D. W.. 1996; Identification of a virulence locus encoding a second type III secretion system in Salmonella typhimurium . Proc Natl Acad Sci U S A93:2593–2597
    [Google Scholar]
  44. Stein M. A., Leung K. Y., Zwick M., García-del Portillo F., Finlay B. B.. 1996; Identification of a Salmonella virulence gene required for formation of filamentous structures containing lysosomal membrane glycoproteins within epithelial cells. Mol Microbiol20:151–164
    [Google Scholar]
  45. Testerman T. L., Vázquez-Torres A., Xu Y., Jones-Carson J., Libby S. J., Fang F. C.. 2002; The alternative sigma factor sigmaE controls antioxidant defences required for Salmonella virulence and stationary-phase survival. Mol Microbiol43:771–782
    [Google Scholar]
  46. Uhl M. A., Miller J. F.. 1994; Autophosphorylation and phosphotransfer in the Bordetella pertussis BvgAS signal transduction cascade. Proc Natl Acad Sci U S A91:1163–1167
    [Google Scholar]
  47. Valdivia R. H., Falkow S.. 1997; Fluorescence-based isolation of bacterial genes expressed within host cells. Science277:2007–2011
    [Google Scholar]
  48. Valdivia R. H., Hromockyj A. E., Monack D., Ramakrishnan L., Falkow S.. 1996; Applications for green fluorescent protein (GFP) in the study of host-pathogen interactions. Gene173:47–52
    [Google Scholar]
  49. Worley M. J., Ching K. H., Heffron F.. 2000; Salmonella SsrB activates a global regulon of horizontally acquired genes. Mol Microbiol36:749–761
    [Google Scholar]
  50. Zaharik M. L., Vallance B. A., Puente J. L., Gros P., Finlay B. B.. 2002; Host-pathogen interactions: host resistance factor Nramp1 up-regulates the expression of Salmonella pathogenicity island-2 virulence genes. Proc Natl Acad Sci U S A99:15705–15710
    [Google Scholar]
  51. Zhou D., Galán J.. 2001; Salmonella entry into host cells: the work in concert of type III secreted effector proteins. Microbes Infect3:1293–1298
    [Google Scholar]
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