Regulation of transcription in Helicobacter pylori: simple systems or complex circuits?

A common strategy used by both Gram-negative and Gram-positive bacterial pathogens is based on the synchronisation of virulence gene expression using a variety of regulatory systems and networks to overcome host defence. During the last decade an exponentially growing number of studies on Helicobacter pylori, a human pathogen associated with diverse stomach diseases, have mainly focussed on the elucidation of mechanisms and functions of virulence factors. A subset of these studies were focussed on the molecular mechanisms regulating gene transcription in H. pylori with the aim of understanding the profound physiological changes that this pathogen, as well as other bacteria, undergoes during infection. Despite the limited number of putative regulatory proteins, as deduced from genome sequence analyses, evidence is accumulating for the existence of new and complex circuits regulating gene transcription and virulence of this bacterium. Here we will focus on the molecular mechanisms used by H. pylori to control gene transcription.