rpe, a cis-acting element from the strA region of the Haemophilus influenzae chromosome that makes plasmid establishment independent of recombination.

Plasmids that share homology with the Haemophilus influenzae chromosome transform wild-type cells more efficiently than they transform recombination-defective mutants. A 5.2-kilobase-pair chromosomal fragment containing the strA gene of H. influenzae was found to promote efficient plasmid establishment in recombination-defective mutants. A cis-acting element in the insert, called rpe for rec-less plasmid establishment, promoted plasmid transformation in rec-1 and rec-2 mutants without suppressing the recombination defects of these strains. The rpe locus increased plasmid transformation in wild-type cells without interfering with the pathway of plasmid establishment that is dependent on recombination functions.