establishment of stable chinese hamster ovary cells expressing codon-optimized human interferon-β gene

Background: codon optimization is an efficient approach to achieve a higher level of heterologous gene expression and generate productive recombinant mammalian cell lines. in our previous work, based on the codon usage preference of chinese hamster ovary (cho) cells, a codon-optimized human interferon-beta (opt-hifn-β) gene was redesigned and transiently expressed in a suspension-adapted cho (cho-s) cell line. our results indicated a 2.8-fold increase in the expression level of the codon-optimized gene compared to the unmodified sequence. objectives: in the current work, based on our previous results, a stable cho-k1 cell line expressing the opt-hifn-β gene was engineered, in which the opt-hifn-β gene expression was confirmed by dot and western blotting analyses. methods: the designed opt-hifn-β sequence was digested and cloned into a pcdna3.0 shuttle vector downstream to the cytomegalovirus (cmv) promoter. the verified recombinant plasmid was then linearized and transfected into a cho-k1 cell line to integrate the opt-hifn-β gene into the cho-k1 genome. the transfected cells were then grown under the selective pressure of 450 µg/ml of g418 to develop a stable cho-k1 cell line expressing the opt-hifn-β gene. the enzyme-linked immunosorbent assay (elisa) and dot and western blotting analyses were carried out to verify hifn-β protein expression. results: elisa and dot and western blotting analyses confirmed the expression of hifn-β in the stably-transfected cho-k1 cells. conclusions: stable expression of the opt-hifn-β gene in the cho-k1 cell line was verified by elisa and dot and western blotting analyses. this study was a pioneering work for further production of recombinant hifn-β in the bioreactor.