Investigating the Role of Helicobacter pylori PriA Protein.

ABSTRACT

BACKGROUND: In bacteria, PriA protein, a conserved DEXH-type DNA helicase, plays a central role in replication restart at stalled replication forks. Its unique DNA binding property allows it to recognize and stabilize stalled forks and the structures derived from them. PriA plays a very critical role in replication fork stabilization and DNA repair in E. coli and N. gonorrhoeae. In our in vivo expression technology screen, priA gene was induced in vivo when Helicobacter pylori infects mouse stomach. MATERIALS AND METHODS: We decided to elucidate the role of H. pylori PriA protein in survival in mouse stomach, survival in gastric epithelial cells and macrophage cells, DNA repair, acid stress, and oxidative stress. RESULTS: The priA null mutant strain was unable to colonize mice stomach mucosa after long-term infections. Mouse colonization was observed after 1 week of infection, but the levels were much lower than the wild-type HpSS1 strain. PriA protein was found to be important for intracellular survival of epithelial cell-/macrophage cell-ingested H. pylori. Also, a priA null mutant was more sensitive to DNA-damaging agents and was much more sensitive to acid and oxidative stress as compared to the wild-type strain. CONCLUSIONS: These data suggest that the PriA protein is needed for survival and persistence of H. pylori in mice stomach mucosa.