Acid-Induced Activation of the Urease Promoters Is Mediated Directly by the ArsRS Two-Component System of Helicobacter pylori

• Published in: Infection and Immunity Vol. 73; no. 10; pp. 6437 - 6445
• Main Authors: Pflock, Michael, Kennard, Simone, Delany, Isabel, Scarlato, Vincenzo, Beier, Dagmar
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.10.2005
• Subjects: Acids - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Base Sequence; Biological and medical sciences; DNA Footprinting; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Helicobacter pylori; Helicobacter pylori - enzymology; Helicobacter pylori - genetics; Histidine Kinase; Hydrogen-Ion Concentration; Membrane Transport Proteins - genetics; Metalloproteins - metabolism; Microbiology; Miscellaneous; Molecular Pathogenesis; Molecular Sequence Data; Mutation; Nickel - metabolism; Operon - genetics; Promoter Regions, Genetic - genetics; Protein Kinases - metabolism; Repressor Proteins - genetics; Repressor Proteins - metabolism; Sequence Deletion; Trans-Activators - metabolism; Urease - genetics; Spirillales; Helicobacter pylori; Microbiology; Enzyme; Spirillaceae; Bacteria; Hydrolases; Urease; Immunity
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.73.10.6437-6445.2005

The nickel-containing enzyme urease is an essential colonization factor of the human gastric pathogen Helicobacter pylori which enables the bacteria to survive the low-pH conditions of the stomach. Transcription of the urease genes is positively controlled in response to increasing concentrations of nickel ions and acidic pH. Here we demonstrate that acid-induced transcription of the urease genes is mediated directly by the ArsRS two-component system. Footprint analyses identify binding sites of the phosphorylated ArsR response regulator within the ureA and ureI promoters. Furthermore, deletion of a distal upstream ArsR binding site of the ureA promoter demonstrates its role in acid-dependent activation of the promoter. In addition, acid-induced transcription of the ureA gene is unaltered in a nikR mutant, providing evidence that pH-responsive regulation and nickel-responsive regulation of the ureA promoter are mediated by independent mechanisms involving the ArsR response regulator and the NikR protein.