An autocatalytic expression system for regulated production of recombinant protein in mammalian cells

An autocatalytic inducible mammalian expression system was established. This system is composed of two sets of vectors: one carries a selectable marker gene and the other carries a bicistronic expression unit consisting of a target gene, an internal ribosomal entry site, and a tetracycline-controlled transactivator gene. Both the selectable marker and the bicistronic unit are controlled by the tetracycline-responsive promoter (PhCMV*-1). When the two vectors are cotransfected into host cells, only a single selection round in the absence of tetracycline is necessary to generate clones expressing the target gene. The expression level is high and easily regulated by tetracycline. Combination with a gene amplification system may allow further enhance the foreign gene expression. Because the PhCMV*-1 promoter is relatively independent of cellular regulation signals, this system is expected to work in a wide variety of cell types.