Absence in Helicobacter pylori of an uptake sequence for enhancing uptake of homospecific DNA during transformation.

Uptake sequences are abundant sequence motifs, often located downstream of ORFs, that are used to facilitate the within-species horizontal transfer of DNA. A frequent word analysis of the complete genome sequence of Helicobacter pylori strain 26685 was performed to search for and determine the identity of an uptake sequence in this species. The results demonstrated that Hel. pylori does not possess an uptake sequence. This is the first naturally transformable Gram-negative species shown to lack such a transformation-targeting system.