HP0333, a member of the dprA family, is involved in natural transformationin Helicobacter pylori

Helicobacter pylori is naturally competent for DNA transformation, but the mechanism by which transformation occurs is not known. For Haemophilus infl uenzae, dprA is required fur transformation by chromosomal but not plasmid DNA, and the complete genomic sequence of H. pylori 26695 revealed a dprA h omolog (HP0333), Examination of genetic databases indicates that DprA homol ogs are present in a wide variety of bacterial species. To examine whether HP0333 has a function similar to dprA of H, influenzae, HP0333, present in each of ii strains studied, was disrupted in two H. pylori isolates, For bo th mutants, the frequency of transformation by H, pylori chromosomal DNA wa s markedly reduced, but not eliminated, compared to their wild-type parenta l strains, Mutation of HP0333 also resulted in a marked decrease in transfo rmation frequency by a shuttle plasmid (pHP1), which differs from the pheno type described in II. influenzae, Complementation of the mutant with HP0333 inserted in trans in the chromosomal ureAB locus completely restored the f requency of transformation to that of the wild-type strain. Thus, while dpr A is required for high-frequency transformation, transformation also may oc cur independently of DprA. The presence of DprA homologs in bacteria known not to be naturally competent suggests a broad function in DNA processing.