Acid-induced activation of the urease promoters is mediated directly by the ArsRS two-component system of Helicobacter pylori.
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.
Pflock
Michael
M
Theodor-Boveri-Institut für Biowissenschaften, Lehrstuhl für Mikrobiologie, Universität Würzburg, Germany.
Kennard
Simone
S
Delany
Isabel
I
Scarlato
Vincenzo
V
Beier
Dagmar
D
D000143:Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018983:DNA Footprinting; D015964:Gene Expression Regulation, Bacterial; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics; D000071677:Histidine Kinase; D006863:Hydrogen-Ion Concentration; D026901:Membrane Transport Proteins / Q000235:genetics; D008667:Metalloproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009532:Nickel / Q000378:metabolism; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D015534:Trans-Activators / Q000378:metabolism*; D014510:Urease / Q000235:genetics*
D000143:Acids; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D008667:Metalloproteins; D012097:Repressor Proteins; D015534:Trans-Activators; C114527:UreI protein, Helicobacter pylori; D009532:Nickel; D011494:Protein Kinases; D000071677:Histidine Kinase; D014510:Urease