CLONING VECTORS FOR POLYPEPTIDE EXPRESSION IN MICROBIAL HOSTS

摘要

The invention relates to a novel class of plasmid cloning vehicles which include a DNA sequence coding for the desired polypeptide linked for transcriptional expression in reading phase with one or more functional fragments derived from an outer membrane protein gene of a gram-negative bacterium. The plasmids also include an inducible promoter sequence positioned in the proper orientation for transcriptional expression of the desired polypeptide, as well as a separate DNA sequence coding for a repressor protein which can interact with the inducible promoter to prevent transcription therefrom. The repressor protein can be selectively inactivated by means of an inducer molecule to permit transcriptional expression of the desired polypeptide. Such plasmids may be used to introduce genetic capability into micro-organisms for the production of proteins, such as medically or commercially useful hormones, enzymes, immunogenic proteins, or intermediates therefor, but only in the presence of an appropriate inducer.