Patent ID: 9657310
Date: 2017-05-23
CPC Classifications: C07K,C12N,C12Y

Claim:
1. An expression vector for expression of a protein, comprising a gene expression regulatory site (A), and a gene encoding the protein downstream thereof, an internal ribosome entry site further downstream thereof, a gene encoding a glutamine synthetase still further downstream thereof, and additionally a dihydrofolate reductase gene downstream of another gene expression regulatory site (B) in addition to the former, wherein the internal ribosome entry site is derived from the 5′ untranslated region of mouse encephalomyocarditis virus, wherein the internal ribosome entry site is that in which the 2nd or 3rd start codon from the 5′ end has been destroyed by introducing one or more mutations into the nucleotide sequence of a wild-type internal ribosome entry site, and wherein the internal ribosome entry site comprises the nucleotide sequence set forth as SEQ ID NO:4.