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

gadX  -  acid resistance regulon transcriptional...

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK3501, JW3484, yhiX
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 gadX


High impact information on gadX

  • Band shift and DNase I footprints reveal that H-NS indeed binds to specific sites in the promoter regions of gadA and gadX and represses the transcription of these genes both in an in vitro system and in vivo [2].
  • Analysis of a gadX mutant grown in the different culture media with acidic and alkaline pH showed that regulation of perA, gadA and gadB by GadX was altered by the external pH and the culture media condition [3].
  • Under conditions in which EPEC infects cultured epithelial cells, GadX negatively regulated perA expression, and the derepression in the gadX mutant increased translocation of Tir into epithelial cells relative to wild-type EPEC [3].
  • The induction of mdtEF by GlcNAc is not mediated by the evgSA, ydeO, gadX, and rpoS signaling pathways that have been known to regulate mdtEF expression [4].
  • A promoter mutation which abolished gadY expression resulted in a reduction in the amount of gadX mRNA during stationary phase [5].

Biological context of gadX

  • However, P(T5)lacO-controlled gadX expression in neutral rich medium results in upregulation of target genes even in exponential phase, i.e., when the gad system is normally repressed [1].
  • The gadX promoter encompasses the 67-bp region preceding the gadX transcription start site and contains both RpoD and RpoS putative recognition sites [1].
  • We suggest that during stationary phase, GadY forms base pairs with the 3'-untranslated region of the gadX mRNA and confers increased stability, allowing for gadX mRNA accumulation and the increased expression of downstream acid resistance genes [5].
  • The gadX gene and a second downstream araC-like transcription factor gene, gadW, were mutated separately and in combination, and the gene expression profiles of the mutants were compared to those of the wild-type strain grown in neutral and acidified media under conditions favoring induction of glutamate-dependent acid resistance [6].

Associations of gadX with chemical compounds

  • However, there was no defect in colonization of the streptomycin-treated mouse model by the gadX mutant in competition with the wild type, and the gadX gadW mutant was a better colonizer than the wild type [6].

Other interactions of gadX

  • GadW clearly represses gadX and, in situations where GadX is missing, activates gadA and gadBC [7].
  • The control loop involves the GadX protein repressing the expression of gadW and the GadW protein repressing or inhibiting RpoS, which is the alternative sigma factor that drives transcription of gadX [8].

Analytical, diagnostic and therapeutic context of gadX


  1. Functional characterization and regulation of gadX, a gene encoding an AraC/XylS-like transcriptional activator of the Escherichia coli glutamic acid decarboxylase system. Tramonti, A., Visca, P., De Canio, M., Falconi, M., De Biase, D. J. Bacteriol. (2002) [Pubmed]
  2. Antagonistic role of H-NS and GadX in the regulation of the glutamate decarboxylase-dependent acid resistance system in Escherichia coli. Giangrossi, M., Zattoni, S., Tramonti, A., De Biase, D., Falconi, M. J. Biol. Chem. (2005) [Pubmed]
  3. An activator of glutamate decarboxylase genes regulates the expression of enteropathogenic Escherichia coli virulence genes through control of the plasmid-encoded regulator, Per. Shin, S., Castanie-Cornet, M.P., Foster, J.W., Crawford, J.A., Brinkley, C., Kaper, J.B. Mol. Microbiol. (2001) [Pubmed]
  4. N-acetyl-d-glucosamine induces the expression of multidrug exporter genes, mdtEF, via catabolite activation in Escherichia coli. Hirakawa, H., Inazumi, Y., Senda, Y., Kobayashi, A., Hirata, T., Nishino, K., Yamaguchi, A. J. Bacteriol. (2006) [Pubmed]
  5. GadY, a small-RNA regulator of acid response genes in Escherichia coli. Opdyke, J.A., Kang, J.G., Storz, G. J. Bacteriol. (2004) [Pubmed]
  6. Genes of the GadX-GadW regulon in Escherichia coli. Tucker, D.L., Tucker, N., Ma, Z., Foster, J.W., Miranda, R.L., Cohen, P.S., Conway, T. J. Bacteriol. (2003) [Pubmed]
  7. Collaborative regulation of Escherichia coli glutamate-dependent acid resistance by two AraC-like regulators, GadX and GadW (YhiW). Ma, Z., Richard, H., Tucker, D.L., Conway, T., Foster, J.W. J. Bacteriol. (2002) [Pubmed]
  8. pH-Dependent modulation of cyclic AMP levels and GadW-dependent repression of RpoS affect synthesis of the GadX regulator and Escherichia coli acid resistance. Ma, Z., Richard, H., Foster, J.W. J. Bacteriol. (2003) [Pubmed]
WikiGenes - Universities