Stabilization of T7-promoter-based pARHS expression vectors using the parB locus

We describe a modification of the pAR3040 vector which results in its efficient stabilization during cell division. The parB locus of the plasmid R1 was introduced into the plasmid, pAR3040, to construct the pARHS vectors. These vectors are stable for at least 60 cell generations, even in the absence of selection by an antibiotic present in the culture media, both with or without IPTG induction.