A genetic system for RNase E variant-controlled overproduction of ColE1-type plasmid DNA.

Escherichia coli endoribonuclease RNase E (Rne) regulates replication of ColE1-type plasmids by cleaving RNA I transcripts, which are synthesized from the plasmid and regulate the plasmid replication as antisense RNA. Here, we report the development of a genetic system that efficiently overproduces ColE1-type plasmid DNA when an RNase E variant that confers a hyperactive phenotype in RNA I cleavage is conditionally expressed from chromosome. This genetic system offers a method for isolation of large quantities of pure ColE1-type plasmid DNA, which have been most commonly used as molecular biology and biotechnology tools for research and industrial purposes.