An Escherichia coli insertion element (IS2) provides a functional promoter in Bordetella pertussis.

The adenylate cyclase (cyaA) gene of Bordetella pertussis is not expressed in Escherichia coli. Using cya-lac fusions, high-expression spontaneous mutants were isolated and shown to have the insertion element IS2 in orientation II integrated into the reading frame of cyaA. Upon transfer of the IS2-activated cya-lac fusion into B. pertussis, we found that the IS2-provided promoter is as efficient in B. pertussis as it is in E. coli. These results provide evidence that an insertion element derived from the E. coli chromosome can activate gene expression in B. pertussis, a taxonomically distant organism.