Helicobacter pylori with separate beta- and beta '-subunits of RNA polymerase is viable and can colonize conventional mice

The genes encoding the beta- and beta '-subunits of RNA polymerase (rpoB en d rpoC respectively) are fused as one continuous open reading frame in Heli cobacter pylori and in other members of this genus, but are separate in oth er bacterial taxonomic groups, including the closely related genus Campylob acter. To test whether this beta-beta ' tethering is essential, we used pol ymerase chain reaction-based cloning to separate the rpoB and rpoC moieties of the H. pylori rpoB-rpoC fusion gene with a non-polar chloramphenicol re sistance cassette containing a new translational start, and introduced this construct into H. pylori by electrotransformation. H. pylori containing th ese separated rpoB and rpoC genes in place of the native fusion gene produc ed non-tethered beta and beta ' RNAP subunits, grew well in culture and col onized and proliferated well in conventional C57BL/8 mice. Thus, the extrao rdinary beta-beta ' tethering is not essential for H. pylori viability and gastric colonization.