Disease relevance of ureI

• ureI encodes an inner membrane protein of Helicobacter pylori [1].

High impact information on ureI

• These data show that VacA behaves as a low-pH activated, passive urea transporter potentially capable of permeabilizing the gastric epithelium to urea [2].
• Changes in urease synthesis or assembly were determined by incubation of the organisms at pH 5.5 or 7.0 in the absence and presence of chloramphenicol, urea, or nickel chelator and in ureI-positive and -negative organisms [3].
• Total bacterial urease activity was increased 3-5-fold by incubation at pH 5.5 in the presence of chloramphenicol but not in nickel-free medium or in ureI knockout organisms [3].
• The transcription start point of ureI was identified by primer extension using a ureA promoter-deleted mutant, and a consensus sequence of RpoD-RNA polymerase was found in the ureI promoter [4].
• Isogenic ureI knockout mutants of several H. pylori strains were constructed by replacing the ureI gene of the urease gene cluster with a promoterless kanamycin resistance marker gene (kanR) [1].

Chemical compound and disease context of ureI

• We also determined ureI expression, urease activity, and the effect of urea on membrane potential of several gastric and nongastric Helicobacter species. ureI was found to be present in the genome of the gastric Helicobacter species and absent in the nongastric Helicobacter species studied, as determined by PCR [5].

Biological context of ureI

• 0. Whereas wild-type bacteria showed high levels of urease activity below pH 4.0, this ability was not retained in the ureI mutants, resulting in inhibition of metabolism and cell death [1].
• This increase of urea permeability is essential for H. pylori survival in environments below pH 4.0. ureI-independent urease activity may be sufficient for maintenance of bacterial viability above pH 4.0 [1].
• To determine the function of UreI protein, we produced H. pylori ureI deletion mutants and measured the pH dependence of urease activity of intact and lysed bacteria and the effect of urea on the membrane potential [5].
• Footprint analyses identify binding sites of the phosphorylated ArsR response regulator within the ureA and ureI promoters [6].
• The gene complex encodes catalytic subunits (ureA/B), an acid-gated urea channel (ureI), and accessory assembly proteins (ureE-H) [7].

Anatomical context of ureI

• Measurement of 14C-urea uptake into Xenopus oocytes injected with ureI cRNA showed acid activation of uptake only in injected oocytes [1].
• ureI encodes an integral cytoplasmic membrane protein [5].
• The eradication of ureI mutants following restoration of acid secretion suggests that the organism is exposed to pH < 4.0 at the surface of the antral mucosa and that UreI provides a target for specific monotherapy of H. pylori infections [8].
• The dominant requirement for acid resistance is the presence of a proton gated urea transporter, UreI, which increases access of gastric juice urea to the intrabacterial urease 300-fold [9].

Other interactions of ureI

• Sequences of internal fragments (542-627 bp) of three housekeeping genes (ureI, ahpC and atpA) were analysed for 85 isolates from individuals in Japan and China (30 isolates), Nigeria and South Africa (14 isolates), the United Kingdom (32 isolates), and nine miscellaneous reference strains [10].
• Moreover, stepwise additions of ureE and ureI to ureFGH significantly increased urease activity [11].

Analytical, diagnostic and therapeutic context of ureI

• We employed pH- and Ca(2+)-sensitive fluorescent dyes and confocal microscopy to determine the location, rate, and magnitude of pH changes in an H. pylori-AGS cell coculture model, comparing wild-type bacteria with nonpolar ureI-deletion strains (ureI-ve) [12].
• Northern blot hybridization analysis demonstrated that cells of the wild-type strain grown in an ordinary broth had transcripts of ureAB, ureABI, ureI, ureIE' and ure'FGH, but cells of a ureI-disrupted mutant had only the ureAB transcript [4].

References