Stability of the pBR322 plasmid as affected by the promoter region of the tetracycline-resistance gene.

A region affecting the pBR322 plasmid maintenance has been located within the region of the TcR gene promoter. On the basis of stability analysis of pBR322 derivatives comprising the modified region of the TcR gene, we deduced that it is the nucleotide sequence localized in the region of the HindIII site that causes destabilization of the plasmid and not the TcR gene product or active transcription of this region. The destabilizing effect is manifested both in cis and in trans.