Isolation and Characterization of OmpR-LacZ protein fusions

Abstract

The ompR gene product of Escherichia coil functions to regulate the expresion of the outer membrane porins OmpF and OmpC. A model has been proposed by Hall and Silhavy (1981a) to explain how ompR functions to regulate these porins. This model proposed that the ompR gene consists of two functional domains ompR1 and ompR2. By constructing and analyzing a series of ompR-lacZ gene fusions we have shown that the ompR gene does in fact consist of these two functional domains. Genetic and DNA sequence analysis of these fusions have aided in defining the regions of the ompR gene necessary for the expresion of OmpF and OmpC. The results suggest that the entire ompR gene is necessary for its full function and that information necessary for ompF expression lies between residues 213 and 237. In addition, one of the ompR-lacZ fusions may prove useful in defining the region of lacZ necessary for formation of the active enzyme.