Skip to main content
PMC home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1996 Dec;178(23):6857–6864. doi: 10.1128/jb.178.23.6857-6864.1996

PhoP-PhoQ activates transcription of pmrAB, encoding a two-component regulatory system involved in Salmonella typhimurium antimicrobial peptide resistance.

J S Gunn 1, S I Miller 1
PMCID: PMC178586  PMID: 8955307

Abstract

Antimicrobial cationic peptides are a host defense mechanism of many animal species including mammals, insects, and amphibians. Salmonella typhimurium is an enteric and intracellular pathogen that interacts with antimicrobial peptides within neutrophil and macrophage phagosomes and at intestinal mucosal surfaces. The Salmonella spp. virulence regulators, PhoP and PhoQ, activate the transcription of genes (pag) within macrophage phagosomes necessary for resistance to cationic antimicrobial peptides. One PhoP-activated gene, pagB, forms an operon with pmrAB (5' pagB-pmrA-pmrB 3'), a two-component regulatory system involved in resistance to the antimicrobial peptides polymyxin, azurocidin (CAP37), bactericidal/permeability-increasing protein (BPI or CAP57), protamine, and polylysine. Expression of pmrAB increased transcription of pagB-pmrAB by activation of a promoter 5' to pagB. pmrAB is also expressed from a second promoter, not regulated by PhoP-PhoQ or PmrA-PmrB, located within the pagB coding sequence. S. typhimurium strains with increased pag locus expression were demonstrated to be polymyxin resistant because of induction of pagB-pmrAB; however, PmrA-PmrB was not responsible for the increased sensitivity of PhoP-null mutants to NP-1 defensin. Therefore, PhoP regulates at least two separate networks of genes responsible for cationic antimicrobial peptide resistance. These data suggest that resistance to the polymyxin-CAP family is controlled by a cascade of regulatory protein expression that activates transcription upon environmental sensing.

Full Text

The Full Text of this article is available as a PDF (275.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alpuche Aranda C. M., Swanson J. A., Loomis W. P., Miller S. I. Salmonella typhimurium activates virulence gene transcription within acidified macrophage phagosomes. Proc Natl Acad Sci U S A. 1992 Nov 1;89(21):10079–10083. doi: 10.1073/pnas.89.21.10079. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Behlau I., Miller S. I. A PhoP-repressed gene promotes Salmonella typhimurium invasion of epithelial cells. J Bacteriol. 1993 Jul;175(14):4475–4484. doi: 10.1128/jb.175.14.4475-4484.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Belden W. J., Miller S. I. Further characterization of the PhoP regulon: identification of new PhoP-activated virulence loci. Infect Immun. 1994 Nov;62(11):5095–5101. doi: 10.1128/iai.62.11.5095-5101.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Buchmeier N. A., Heffron F. Intracellular survival of wild-type Salmonella typhimurium and macrophage-sensitive mutants in diverse populations of macrophages. Infect Immun. 1989 Jan;57(1):1–7. doi: 10.1128/iai.57.1.1-7.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chan R. K., Botstein D., Watanabe T., Ogata Y. Specialized transduction of tetracycline resistance by phage P22 in Salmonella typhimurium. II. Properties of a high-frequency-transducing lysate. Virology. 1972 Dec;50(3):883–898. doi: 10.1016/0042-6822(72)90442-4. [DOI] [PubMed] [Google Scholar]
  6. Fields P. I., Groisman E. A., Heffron F. A Salmonella locus that controls resistance to microbicidal proteins from phagocytic cells. Science. 1989 Feb 24;243(4894 Pt 1):1059–1062. doi: 10.1126/science.2646710. [DOI] [PubMed] [Google Scholar]
  7. Fields P. I., Swanson R. V., Haidaris C. G., Heffron F. Mutants of Salmonella typhimurium that cannot survive within the macrophage are avirulent. Proc Natl Acad Sci U S A. 1986 Jul;83(14):5189–5193. doi: 10.1073/pnas.83.14.5189. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Ganz T., Selsted M. E., Szklarek D., Harwig S. S., Daher K., Bainton D. F., Lehrer R. I. Defensins. Natural peptide antibiotics of human neutrophils. J Clin Invest. 1985 Oct;76(4):1427–1435. doi: 10.1172/JCI112120. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. García Véscovi E., Soncini F. C., Groisman E. A. Mg2+ as an extracellular signal: environmental regulation of Salmonella virulence. Cell. 1996 Jan 12;84(1):165–174. doi: 10.1016/s0092-8674(00)81003-x. [DOI] [PubMed] [Google Scholar]
  10. Gray P. W., Flaggs G., Leong S. R., Gumina R. J., Weiss J., Ooi C. E., Elsbach P. Cloning of the cDNA of a human neutrophil bactericidal protein. Structural and functional correlations. J Biol Chem. 1989 Jun 5;264(16):9505–9509. [PubMed] [Google Scholar]
  11. Groisman E. A., Chiao E., Lipps C. J., Heffron F. Salmonella typhimurium phoP virulence gene is a transcriptional regulator. Proc Natl Acad Sci U S A. 1989 Sep;86(18):7077–7081. doi: 10.1073/pnas.86.18.7077. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Groisman E. A., Parra-Lopez C., Salcedo M., Lipps C. J., Heffron F. Resistance to host antimicrobial peptides is necessary for Salmonella virulence. Proc Natl Acad Sci U S A. 1992 Dec 15;89(24):11939–11943. doi: 10.1073/pnas.89.24.11939. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Gunn J. S., Alpuche-Aranda C. M., Loomis W. P., Belden W. J., Miller S. I. Characterization of the Salmonella typhimurium pagC/pagD chromosomal region. J Bacteriol. 1995 Sep;177(17):5040–5047. doi: 10.1128/jb.177.17.5040-5047.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Gunn J. S., Hohmann E. L., Miller S. I. Transcriptional regulation of Salmonella virulence: a PhoQ periplasmic domain mutation results in increased net phosphotransfer to PhoP. J Bacteriol. 1996 Nov;178(21):6369–6373. doi: 10.1128/jb.178.21.6369-6373.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Helander I. M., Kilpeläinen I., Vaara M. Increased substitution of phosphate groups in lipopolysaccharides and lipid A of the polymyxin-resistant pmrA mutants of Salmonella typhimurium: a 31P-NMR study. Mol Microbiol. 1994 Feb;11(3):481–487. doi: 10.1111/j.1365-2958.1994.tb00329.x. [DOI] [PubMed] [Google Scholar]
  16. Hohmann E. L., Oletta C. A., Killeen K. P., Miller S. I. phoP/phoQ-deleted Salmonella typhi (Ty800) is a safe and immunogenic single-dose typhoid fever vaccine in volunteers. J Infect Dis. 1996 Jun;173(6):1408–1414. doi: 10.1093/infdis/173.6.1408. [DOI] [PubMed] [Google Scholar]
  17. Kier L. D., Weppelman R., Ames B. N. Regulation of two phosphatases and a cyclic phosphodiesterase of Salmonella typhimurium. J Bacteriol. 1977 Apr;130(1):420–428. doi: 10.1128/jb.130.1.420-428.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Mekalanos J. J. Duplication and amplification of toxin genes in Vibrio cholerae. Cell. 1983 Nov;35(1):253–263. doi: 10.1016/0092-8674(83)90228-3. [DOI] [PubMed] [Google Scholar]
  19. Michaelis S., Inouye H., Oliver D., Beckwith J. Mutations that alter the signal sequence of alkaline phosphatase in Escherichia coli. J Bacteriol. 1983 Apr;154(1):366–374. doi: 10.1128/jb.154.1.366-374.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Miller S. I., Kukral A. M., Mekalanos J. J. A two-component regulatory system (phoP phoQ) controls Salmonella typhimurium virulence. Proc Natl Acad Sci U S A. 1989 Jul;86(13):5054–5058. doi: 10.1073/pnas.86.13.5054. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Miller S. I., Mekalanos J. J. Constitutive expression of the phoP regulon attenuates Salmonella virulence and survival within macrophages. J Bacteriol. 1990 May;172(5):2485–2490. doi: 10.1128/jb.172.5.2485-2490.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Miller S. I., Pulkkinen W. S., Selsted M. E., Mekalanos J. J. Characterization of defensin resistance phenotypes associated with mutations in the phoP virulence regulon of Salmonella typhimurium. Infect Immun. 1990 Nov;58(11):3706–3710. doi: 10.1128/iai.58.11.3706-3710.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Miller V. L., Mekalanos J. J. A novel suicide vector and its use in construction of insertion mutations: osmoregulation of outer membrane proteins and virulence determinants in Vibrio cholerae requires toxR. J Bacteriol. 1988 Jun;170(6):2575–2583. doi: 10.1128/jb.170.6.2575-2583.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Nelson D. L., Kennedy E. P. Magnesium transport in Escherichia coli. Inhibition by cobaltous ion. J Biol Chem. 1971 May 10;246(9):3042–3049. [PubMed] [Google Scholar]
  25. Parra-Lopez C., Baer M. T., Groisman E. A. Molecular genetic analysis of a locus required for resistance to antimicrobial peptides in Salmonella typhimurium. EMBO J. 1993 Nov;12(11):4053–4062. doi: 10.1002/j.1460-2075.1993.tb06089.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Parra-Lopez C., Lin R., Aspedon A., Groisman E. A. A Salmonella protein that is required for resistance to antimicrobial peptides and transport of potassium. EMBO J. 1994 Sep 1;13(17):3964–3972. doi: 10.1002/j.1460-2075.1994.tb06712.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Pohl J., Pereira H. A., Martin N. M., Spitznagel J. K. Amino acid sequence of CAP37, a human neutrophil granule-derived antibacterial and monocyte-specific chemotactic glycoprotein structurally similar to neutrophil elastase. FEBS Lett. 1990 Oct 15;272(1-2):200–204. doi: 10.1016/0014-5793(90)80484-z. [DOI] [PubMed] [Google Scholar]
  28. Roland K. L., Martin L. E., Esther C. R., Spitznagel J. K. Spontaneous pmrA mutants of Salmonella typhimurium LT2 define a new two-component regulatory system with a possible role in virulence. J Bacteriol. 1993 Jul;175(13):4154–4164. doi: 10.1128/jb.175.13.4154-4164.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Selsted M. E., Miller S. I., Henschen A. H., Ouellette A. J. Enteric defensins: antibiotic peptide components of intestinal host defense. J Cell Biol. 1992 Aug;118(4):929–936. doi: 10.1083/jcb.118.4.929. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Shafer W. M., Martin L. E., Spitznagel J. K. Cationic antimicrobial proteins isolated from human neutrophil granulocytes in the presence of diisopropyl fluorophosphate. Infect Immun. 1984 Jul;45(1):29–35. doi: 10.1128/iai.45.1.29-35.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Soncini F. C., Véscovi E. G., Groisman E. A. Transcriptional autoregulation of the Salmonella typhimurium phoPQ operon. J Bacteriol. 1995 Aug;177(15):4364–4371. doi: 10.1128/jb.177.15.4364-4371.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Spitznagel J. K. Antibiotic proteins of human neutrophils. J Clin Invest. 1990 Nov;86(5):1381–1386. doi: 10.1172/JCI114851. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Stinavage P., Martin L. E., Spitznagel J. K. O antigen and lipid A phosphoryl groups in resistance of Salmonella typhimurium LT-2 to nonoxidative killing in human polymorphonuclear neutrophils. Infect Immun. 1989 Dec;57(12):3894–3900. doi: 10.1128/iai.57.12.3894-3900.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Storm D. R., Rosenthal K. S., Swanson P. E. Polymyxin and related peptide antibiotics. Annu Rev Biochem. 1977;46:723–763. doi: 10.1146/annurev.bi.46.070177.003451. [DOI] [PubMed] [Google Scholar]
  36. Vaara M. Agents that increase the permeability of the outer membrane. Microbiol Rev. 1992 Sep;56(3):395–411. doi: 10.1128/mr.56.3.395-411.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Vaara M. Increased outer membrane resistance to ethylenediaminetetraacetate and cations in novel lipid A mutants. J Bacteriol. 1981 Nov;148(2):426–434. doi: 10.1128/jb.148.2.426-434.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Vaara M., Vaara T., Jensen M., Helander I., Nurminen M., Rietschel E. T., Mäkelä P. H. Characterization of the lipopolysaccharide from the polymyxin-resistant pmrA mutants of Salmonella typhimurium. FEBS Lett. 1981 Jun 29;129(1):145–149. doi: 10.1016/0014-5793(81)80777-6. [DOI] [PubMed] [Google Scholar]
  39. Vaara M., Vaara T., Sarvas M. Decreased binding of polymyxin by polymyxin-resistant mutants of Salmonella typhimurium. J Bacteriol. 1979 Aug;139(2):664–667. doi: 10.1128/jb.139.2.664-667.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES