AN ESCHERICHIA-COLI HOST STRAIN USEFUL FOR EFFICIENT OVERPRODUCTION OF CLONED GENE-PRODUCTS WITH NACL AS THE INDUCER

Salt-induced overexpression of genes cloned downstream of the phage T7 phi 10 promoter was demonstrated in an Escherichia coli strain (GJ115 8) which carries a single chromosomally integrated copy of the gene fo r phage T7 RNA polymerase under transcriptional control of the cis-reg ulatory elements of the osmoresponsive proU operon. Plasmids that have been constructed to obtain overproduction of individual target gene p roducts in strain BL21(DE3) (by addition of isopropyl-beta-D-thiogalac topyranoside as an inducer) can directly be transformed into GJ1158. T he NaCl induction regimen aas also shown to be associated with a decre ased propensity for sequestration of overexpressed target proteins wit hin insoluble inclusion bodies.