Host dependenet inactivation by IS2 of induced E.coli penicillin amidase gene cloned on multicopy plasmids

TLDR: The results indicated that the induction of the plasmid cloned gene was the main factor which rendered it a target for inactivation by insertions of the host encoded IS2 elements.

Abstract: Structural instability of the cloned penicillin acylase gene (pac) from E.coli ATCC11105 was studied under various physiological conditions. Structural changes which adversely affect the expression of penicillin acylase gene were selected for only under conditions in which the gene was active and fully induced. In E.coli strain YMC the predominant mutations were the insertions of the IS2 element at various sites within the 700 bp proximal portion of the pac gene. The results indicated that the induction of the plasmid cloned gene was the main factor which rendered it a target for inactivation by insertions of the host encoded IS2 elements. The mutational events were host specific and they were not influenced by mutual positions and orientations of key marker genes on the plasmid.