Patent ID: 9096878
Filing Date: 2015-08-04
Classification: C12N,C12P

Abstract:
1. An expression vector for producing a foreign gene-derived protein in a mammalian host cell, which comprises: (a) a translation-impaired dihydrofolate reductase gene cassette (translation-impaired DHFR gene cassette) comprising a region with rare codons wherein the rare codons comprise GCA for alanine, CGA for arginine, AAU for asparagine, GAU for aspartic acid, UGU for cysteine, CAA for glutamine, GAA for glutamic acid, GGU for glycine, CAU for histidine, UUA for leucine, AAA for lysine, CCA for proline, UUU for phenylalanine, UCA for serine, ACU for threonine, UAU for tyrosine, and/or GUA for valine, wherein from the 5′ end of the DHFR gene, each of at least the first 30% of the DHFR gene codons is replaced by the rare codon encoding the same amino acid as the DHFR gene codon, wherein the translation-impaired DHFR gene cassette uses a promoter whose enhancer portion has been removed; and (b) a gene cassette comprising a cloning site for integration of a foreign gene between a transcriptionally active promoter and a stable polyadenylation signal.