Enhancing gene expression through stabilization of mRNA in Escherichia coli

Abstract

Expression level of a gene can be modulated by changing stability of mRNA in Escherichia coli. In order to develop an efficient E. coli expression system, the effects of secondary structures on the 5-untranslated region (5''-UTR) of mRNA and heat shock proteins on stability of mRNA were studied. The plasmids conferring different stem-loop structures on the 5''-end of mRNA (pHY1, pHY2, pHY3, and pHY4) were constructed and the genes encoding amylase were tested. The degree of stabilization was varied depending on the stem-loop structures. As an additional stabilizing factor, coexpressed heat shock proteins DnaKJ, GrpE, GroELS encoded by pG-KJE6, or GroELS encoded by pGro7, were involved in the stabilization of mRNA. The degree of stabilization was varied depending on the stem-loop structures and variety of heat shock proteins. These results suggest that secondary structures and heat shock proteins can enhance gene expression by stabilizing mRNA.