Disease relevance of xylS

• Nucleotide sequence of the regulatory gene xylS on the Pseudomonas putida TOL plasmid and identification of the protein product [1].
• Determination of the polynucleotide sequence of the xylS gene revealed amino acid sequence homology with several DNA binding proteins, particularly with the araC products of Escherichia coli and Salmonella typhimurium and with the nifA and ntrC products of Klebsiella pneumoniae [2].
• Evidence is presented that suggests the promoter operator of the meta pathway gene functions less effectively with the RNA polymerase or xylS product of E. coli than with the enzyme or product of P. putida [3].

High impact information on xylS

• Expression of the meta-cleavage pathway operon of TOL plasmid pWW0 of Pseudomonas putida is positively regulated by the xylS gene product [4].
• The results of the above experiments provide evidence that xylR positively controls the transcription of xylS in the presence of m-xylene or m-methylbenzyl alcohol [5].
• The regulatory gene xylS on the TOL plasmid of Pseudomonas putida activates the transcription of the xylDLEGF operon for the m-toluate-degrading pathway in the presence of m-toluate [5].
• Expression of the meta pathway is also induced by toluene/xylene-activated XylR protein via a cascade regulatory system in which this protein in combination with NtrA protein stimulates transcription from the xylS gene promoter [6].
• Bestowing Inducibility on the Cloned Methanol Dehydrogenase Promoter (PmxaF) of Methylobacterium extorquens by Applying Regulatory Elements of Pseudomonas putida F1 [7].

Chemical compound and disease context of xylS

• The xylS gene is a regulatory gene which positively controls expression of the genes on the TOL plasmid for degradation enzymes of benzoate or m-toluate in Pseudomonas putida [1].
• Transcription from the promoter of a positive regulatory gene, xylS, on the TOL plasmid of Pseudomonas putida is activated by another positive regulator, XylR, in the presence of m-xylene and is dependent on RNA polymerase containing the NtrA protein (sigma 54) [8].
• The pKT530 plasmid also carries xylS (a gene whose product has been postulated to regulate expression of the lower pathway genes) and the control sequences of the pathway that interact with this product, because catechol 2,3-oxygenase synthesis is specifically induced by m-toluate in both P. putida and E. coli [3].

Biological context of xylS

• The first, the upper operon, is controlled by the xylR regulatory gene, whereas the second, the meta operon, is controlled by the xylS regulatory gene [9].
• Deletion analysis of the upstream region of the xylS gene revealed an upstream regulatory sequence (URS), located between 145 and 188 bp upstream from the transcription start site [8].
• Upstream binding sequences of the XylR activator protein and integration host factor in the xylS gene promoter region of the Pseudomonas TOL plasmid [10].
• The Ps2 promoter was located 110 bp downstream from a previously described sigma54-dependent promoter located upstream from the xylS open reading frame, now called Ps1 [11].
• These vectors contain the minimal replicon of RK2 and the inducible Pu or Pm promoters together with their regulatory xylR or xylS genes, respectively, from the Pseudomonas putida TOL plasmid pWWO [12].

Associations of xylS with chemical compounds

• Alternatively, in cells growing on toluene or its aromatic alcohols, overexpression of xylS mediated by XylR activated by these compounds leads to overproduction of the XylS regulator, which even in the absence of benzoate effectors stimulates transcription from the meta cleavage pathway operon promoter [11].
• The xylR and xylS genes are divergent and control transcription of the TOL plasmid catabolic pathways for toluene metabolism [13].
• We show here that in bacteria growing on glycerol or alkylbenzoates, the xylS gene is expressed at a low but constitutive level from a newly found sigma 70-dependent promoter called Ps2 [11].
• When either benR or xylS was cloned into plasmids compatible with those plasmids containing only the benABCD regions, benzoate was removed from the medium and catechol was produced [14].
• The mRNA level of xylS during nonlimited growth on succinate was very low compared with that in succinate-limited cultures, suggesting that suppression of expression of the meta-cleavage pathway is regulated mainly by the level of the XylS regulator [15].

Regulatory relationships of xylS

• The xylS gene itself is subjected to control by xylR [9].

Other interactions of xylS

• Four recombinant mini-Tn5 transposons are described which contain outward-facing Pm, Pu or Psal promoters from the catabolic plasmids TOL and NAH of Pseudomonas putida, along with their cognate wild-type regulatory genes (xylS, xylR, nahR) or mutant varieties (xylS2) [16].

Analytical, diagnostic and therapeutic context of xylS

• The xylS gene positive regulator of TOL plasmid pWWO: identification, sequence analysis and overproduction leading to constitutive expression of meta cleavage operon [2].
• These bacterial biosensors are based on fusions of a promoter that is sensitive to aromatic compounds (the promoter region of the xylS gene and the xylR gene coding for the transcriptional regulator of the xyl operon) to reporter genes that can be monitored electrochemically at real-time and on-line [17].
• Molecular cloning of gene xylS of the TOL plasmid: evidence for positive regulation of the xylDEGF operon by xylS [18].

References