The Helicobacter pylori UreI Protein Is Not Involved in Urease Activity but Is Essential for Bacterial Survival In Vivo

AUTOR(ES)

Skouloubris, Stéphane

FONTE

American Society for Microbiology

RESUMO

We produced defined isogenic Helicobacter pylori ureI mutants to investigate the function of UreI, the product of one of the genes of the urease cluster. The insertion of a cat cassette had a strong polar effect on the expression of the downstream urease genes, resulting in very weak urease activity. Urease activity, measured in vitro, was normal in a strain in which ureI was almost completely deleted and replaced with a nonpolar cassette. In contrast to previous reports, we thus found that the product of ureI was not necessary for the synthesis of active urease. Experiments with the mouse-adapted H. pylori SS1 strain carrying the nonpolar ureI deletion showed that UreI is essential for H. pylori survival in vivo and/or colonization of the mouse stomach. The replacement of ureI with the nonpolar cassette strongly reduced H. pylori survival in acidic conditions (1-h incubation in phosphate-buffered saline solution at pH 2.2) in the presence of 10 mM urea. UreI is predicted to be an integral membrane protein and may therefore be involved in a transport process essential for H. pylori survival in vivo.

Documentos Relacionados

• Expression of the Helicobacter pylori ureI Gene Is Required for Acidic pH Activation of Cytoplasmic Urease
• Helicobacter pylori rocF Is Required for Arginase Activity and Acid Protection In Vitro but Is Not Essential for Colonization of Mice or for Urease Activity
• Dependence of Helicobacter pylori Urease Activity on the Nickel-Sequestering Ability of the UreE Accessory Protein
• Inhibition of urease activity but not growth of Helicobacter pylori by acetohydroxamic acid.
• γ-Glutamyltransferase Is a Helicobacter pylori Virulence Factor but Is Not Essential for Colonization