Characterization of Helicobacter pylori factors that control transformation frequency and integration length during inter-strain DNA recombination.

Publication Type:

Journal Article

Authors:

Humbert, Olivier; Dorer, Marion S; Salama, Nina R

Source:

Molecular microbiology, Volume 79, Issue 2, p.387-401 (2011)

Keywords:

2011, Bacterial Proteins, Deoxyribonucleases, DNA Helicases, DNA Restriction-Modification Enzymes, DNA, Bacterial, Helicobacter pylori, Human Biology Division, Recombinases, Recombination, Genetic, Transformation, Bacterial

Abstract:

Helicobacter pylori is a genetically diverse bacterial species, owing in part to its natural competence for DNA uptake that facilitates recombination between strains. Inter-strain DNA recombination occurs during human infection and the H. pylori genome is in linkage equilibrium worldwide. Despite this high propensity for DNA exchange, little is known about the factors that limit the extent of recombination during natural transformation. Here, we identify restriction-modification (R-M) systems as a barrier to transformation with homeologous DNA and find that R-M systems and several components of the recombination machinery control integration length. Type II R-M systems, the nuclease nucT and resolvase ruvC reduced integration length whereas the helicase recG increased it. In addition, we characterized a new factor that promotes natural transformation in H. pylori, dprB. Although free recombination has been widely observed in H. pylori, our study suggests that this bacterium uses multiple systems to limit inter-strain recombination.