The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
Gene Review

ssrB  -  secretion system transcriptonal activator...

Salmonella enterica subsp. enterica serovar Typhimurium str. LT2

Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of ssrB

  • Identification and characterization of mutants with increased expression of hilA, the invasion gene transcriptional activator of Salmonella typhimurium [1].
  • Protein crosslinking studies suggest that Rhizobium meliloti C4-dicarboxylic acid transport protein D, a sigma 54-dependent transcriptional activator, interacts with sigma 54 and the beta subunit of RNA polymerase [2].
  • Expression of the cysteine regulon in Salmonella typhimurium and Escherichia coli is controlled by the LysR-type transcriptional activator CysB and by the inducer N-acetyl-L-serine [3].

High impact information on ssrB

  • Genes belonging to the adaptive response are positively regulated by the ada gene; the Ada protein acts as a transcriptional activator when methylated in one of its cysteine residues at position 69 [4].
  • The traJ gene of the virulence plasmid of Salmonella enterica serovar Typhimurium (pSLT) encodes a transcriptional activator of the transfer operon [5].
  • The isolated C-terminus of SsrB binds to DNA and protects regions upstream of ssrA, ssrB and srfH from DNase I digestion [6].
  • However, despite the improved interaction with the transcriptional activator, the altered regulatory region was poorer at promoting spvR gene transcription than the wild type [7].
  • Conjugation of Agrobacterium tumefaciens wide-host-range octopine-type Ti plasmids is regulated by the LuxR-type transcriptional activator TraR in conjunction with an acylated homoserine lactone designated AAI [8].

Chemical compound and disease context of ssrB


Biological context of ssrB

  • Results from DNase I protection assays provide direct evidence that SsrB binds at ssrA and ssrB, although the binding sites lie within the transcribed regions [6].
  • The hilA gene, encoded on Salmonella pathogenicity island 1 (SPI-1), is a transcriptional activator which is required for invasion and whose expression is modulated by oxygen, pH, and osmolarity [1].
  • The transcriptional activator FlhD2C2 is the master regulator of bacterial flagellum biogenesis and swarming migration, activating the "early" class II promoters of the large flagellar gene hierarchy [13].
  • The genetic regulation of gogB in Salmonella is influenced by the transcriptional activator, SsrB, under SPI-2-inducing conditions, but the modular nature of the gogB gene allows for autonomous expression and type III secretion following horizontal gene transfer into a heterologous pathogen [14].
  • In vivo titration of transcriptional activator UhpA by the intact or mutant promoters on multicopy plasmids identified the -64 element as the UhpA-binding site [15].

Anatomical context of ssrB

  • Transcription of the hilA gene, which encodes an OmpR/ToxR-type transcriptional activator of downstream invasion genes, is increased during growth under high-osmolarity and low-oxygen conditions, which presumably mimic the environment found within the small intestine [16].
  • However, neither SirA nor HilA is believed to directly activate the promoters of these genes. invF, the first gene of the inv-spa gene cluster, is predicted to encode an AraC-type transcriptional activator and is required for invasion into cultured epithelial cells [17].

Associations of ssrB with chemical compounds

  • These data are consistent with a role for PchR as a transcriptional activator of pyochelin and ferripyochelin receptor synthesis in P. aeruginosa [18].
  • A model for control of this regulon suggests that the PocR protein is a transcriptional activator of both the cob and pdu operons and that both glycerol and propanediol can individually serve as effectors of the PocR protein [19].
  • These activities are thought to be mediated by interactions of the ATPase subunit, MalK, with the transcriptional activator, MalT, and nonphosphorylated enzyme IIA of the glucose phosphotransferase system, respectively [20].

Other interactions of ssrB

  • Strains with mutations in either gene of the regulatory pair (phoP [transcriptional activator] or phoQ [membrane sensor kinase]) had increased sensitivities to defensin [21].
  • We also provide direct evidence for the regulation of SPI-2 by the Salmonella transcription factors ompR and ssrB in vivo [22].

Analytical, diagnostic and therapeutic context of ssrB

  • Transcriptional fusions and Northern blot analysis demonstrated that the aarG1 allele also resulted in a large increase in the expression of aarP, a gene encoding a transcriptional activator of aac(2')-Ia [23].


  1. Identification and characterization of mutants with increased expression of hilA, the invasion gene transcriptional activator of Salmonella typhimurium. Fahlen, T.F., Mathur, N., Jones, B.D. FEMS Immunol. Med. Microbiol. (2000) [Pubmed]
  2. Protein crosslinking studies suggest that Rhizobium meliloti C4-dicarboxylic acid transport protein D, a sigma 54-dependent transcriptional activator, interacts with sigma 54 and the beta subunit of RNA polymerase. Lee, J.H., Hoover, T.R. Proc. Natl. Acad. Sci. U.S.A. (1995) [Pubmed]
  3. In vitro characterization of constitutive CysB proteins from Salmonella typhimurium. Colyer, T.E., Kredich, N.M. Mol. Microbiol. (1996) [Pubmed]
  4. Transcriptional activation of the Escherichia coli adaptive response gene aidB is mediated by binding of methylated Ada protein. Evidence for a new consensus sequence for Ada-binding sites. Landini, P., Volkert, M.R. J. Biol. Chem. (1995) [Pubmed]
  5. Regulation of traJ transcription in the Salmonella virulence plasmid by strand-specific DNA adenine hemimethylation. Camacho, E.M., Casadesús, J. Mol. Microbiol. (2005) [Pubmed]
  6. The response regulator SsrB activates transcription and binds to a region overlapping OmpR binding sites at Salmonella pathogenicity island 2. Feng, X., Walthers, D., Oropeza, R., Kenney, L.J. Mol. Microbiol. (2004) [Pubmed]
  7. In vivo analysis of the interactions of the LysR-like regulator SpvR with the operator sequences of the spvA and spvR virulence genes of Salmonella typhimurium. Sheehan, B.J., Dorman, C.J. Mol. Microbiol. (1998) [Pubmed]
  8. Localization of OccR-activated and TraR-activated promoters that express two ABC-type permeases and the traR gene of Ti plasmid pTiR10. Fuqua, C., Winans, S.C. Mol. Microbiol. (1996) [Pubmed]
  9. Residue threonine-149 of the Salmonella typhimurium CysB transcription activator: mutations causing constitutive expression of positively regulated genes of the cysteine regulon. Colyer, T.E., Kredich, N.M. Mol. Microbiol. (1994) [Pubmed]
  10. Hydroxyl radical footprints and half-site arrangements of binding sites for the CysB transcriptional activator of Salmonella typhimurium. Hryniewicz, M.M., Kredich, N.M. J. Bacteriol. (1995) [Pubmed]
  11. A rationale for autoinduction of a transcriptional activator: ethanolamine ammonia-lyase (EutBC) and the operon activator (EutR) compete for adenosyl-cobalamin in Salmonella typhimurium. Sheppard, D.E., Roth, J.R. J. Bacteriol. (1994) [Pubmed]
  12. Homology between virF, the transcriptional activator of the Yersinia virulence regulon, and AraC, the Escherichia coli arabinose operon regulator. Cornelis, G., Sluiters, C., de Rouvroit, C.L., Michiels, T. J. Bacteriol. (1989) [Pubmed]
  13. Interaction of the atypical prokaryotic transcription activator FlhD2C2 with early promoters of the flagellar gene hierarchy. Claret, L., Hughes, C. J. Mol. Biol. (2002) [Pubmed]
  14. Genetic and molecular analysis of GogB, a phage-encoded type III-secreted substrate in Salmonella enterica serovar typhimurium with autonomous expression from its associated phage. Coombes, B.K., Wickham, M.E., Brown, N.F., Lemire, S., Bossi, L., Hsiao, W.W., Brinkman, F.S., Finlay, B.B. J. Mol. Biol. (2005) [Pubmed]
  15. Promoter elements required for positive control of transcription of the Escherichia coli uhpT gene. Merkel, T.J., Nelson, D.M., Brauer, C.L., Kadner, R.J. J. Bacteriol. (1992) [Pubmed]
  16. Lon protease activity causes down-regulation of Salmonella pathogenicity island 1 invasion gene expression after infection of epithelial cells. Boddicker, J.D., Jones, B.D. Infect. Immun. (2004) [Pubmed]
  17. InvF is required for expression of genes encoding proteins secreted by the SPI1 type III secretion apparatus in Salmonella typhimurium. Darwin, K.H., Miller, V.L. J. Bacteriol. (1999) [Pubmed]
  18. Cloning and sequence analysis of a gene (pchR) encoding an AraC family activator of pyochelin and ferripyochelin receptor synthesis in Pseudomonas aeruginosa. Heinrichs, D.E., Poole, K. J. Bacteriol. (1993) [Pubmed]
  19. A single regulatory gene integrates control of vitamin B12 synthesis and propanediol degradation. Bobik, T.A., Ailion, M., Roth, J.R. J. Bacteriol. (1992) [Pubmed]
  20. Functional characterization of the maltose ATP-binding-cassette transporter of Salmonella typhimurium by means of monoclonal antibodies directed against the MalK subunit. Stein, A., Seifert, M., Volkmer-Engert, R., Siepelmeyer, J., Jahreis, K., Schneider, E. Eur. J. Biochem. (2002) [Pubmed]
  21. Characterization of defensin resistance phenotypes associated with mutations in the phoP virulence regulon of Salmonella typhimurium. Miller, S.I., Pulkkinen, W.S., Selsted, M.E., Mekalanos, J.J. Infect. Immun. (1990) [Pubmed]
  22. Salmonella pathogenicity island 2 is expressed prior to penetrating the intestine. Brown, N.F., Vallance, B.A., Coombes, B.K., Valdez, Y., Coburn, B.A., Finlay, B.B. PLoS Pathog. (2005) [Pubmed]
  23. A regulatory cascade involving AarG, a putative sensor kinase, controls the expression of the 2'-N-acetyltransferase and an intrinsic multiple antibiotic resistance (Mar) response in Providencia stuartii. Rather, P.N., Paradise, M.R., Parojcic, M.M., Patel, S. Mol. Microbiol. (1998) [Pubmed]
WikiGenes - Universities