Control system for suppressing expression of heterologous protein

摘要

(1) Control system for suppressing the expression of a gene encoding a protein heterologous to a prokaryotic host is new when it comprises (a) a first DNA sequence comprising a promoter/ operator operably linked to the gene encoding the protein; and (b) a second DNA sequence comprising an inducible promoter operably linked to the gene encoding a repressor protein compatible with the promoter/operator and supplementary to the host. The two DNA sequences are xenogenic to the host. Expression vector effective in prokaryotic host cells in expressing a gene encoding a desired protein heterologous to the host and comprises a control system as defined above is new. Cells or cell culture transformed with a vector as defined above are new.