Repeated sequence motifs in the Helicobacter pylori P1408 promoter do not affect its transcription.

The ArsRS two-component system controls the pH-dependent transcription of several target genes involved in the acid resistance of Helicobacter pylori. In its phosphorylated form the response regulator ArsR activates transcription of the urease genes and it has been reported that ArsR approximately P binds to a 26 bp consensus motif which is present in the promoter regions of the ORFs hp1408, hp119 and hp1432 encoding proteins of unknown function. Here we show that the upstream region of ORF hp1408 exhibits considerable sequence variation in different isolates of H. pylori. By the construction of fusions of the P(1408) promoter from different H. pylori strains to the reporter gene gfp in the genetic background of H. pylori G27 we demonstrate that these sequence variations do not significantly affect acid-induced transcription. Furthermore, we show that a P(1408) core promoter comprising only the -10 promoter element and the 26 bp ArsR binding site overlapping the -35 region is sufficient for eliciting the normal acid response of ORF hp1408.