Figure 1From: Engineering selection stringency on expression vector for the production of recombinant human alpha1-antitrypsin using Chinese Hamster ovary cellsIllustrations of dhfr selection marker attenuation. (A) Nucleotide sequence of wild type (WT) and codon deoptimized (CDD) dhfr. Nucleotide changes are marked with * and new tandem codon pairs are underlined. (B) Vector map for vector sets with selection marker attenuation by destabilizing peptide, mutant IRES or codon deoptimization.Back to article page