title: Enhanced expression of codon optimized interferon gamma in CHO cells.
abstract: The human interferon-gamma (IFN-γ) is a potential drug candidate for treating various diseases due to its immunomodulatory properties. The efficient production of this protein can be achieved through a popular industrial host, Chinese hamster ovary (CHO) cells. However, recombinant expression of foreign proteins is typically suboptimal possibly due to the usage of non-native codon patterns within the coding sequence. Therefore, we demonstrated the application of a recently developed codon optimization approach to design synthetic IFN-γ coding sequences for enhanced heterologous expression in CHO cells. For codon optimization, earlier studies suggested to establish the target usage distribution pattern in terms of selected design parameters such as individual codon usage (ICU) and codon context (CC), mainly based on the host's highly expressed genes. However, our RNA-Seq based transcriptome profiling indicated that the ICU and CC distribution patterns of different gene expression classes in CHO cell are relatively similar, unlike other microbial expression hosts, Escherichia coli and Saccharomyces cerevisiae. This finding was further corroborated through the in vivo expression of various ICU and CC optimized IFN-γ in CHO cells. Interestingly, the CC-optimized genes exhibited at least 13-fold increase in expression level compared to the wild-type IFN-γ while a maximum of 10-fold increase was observed for the ICU-optimized genes. Although design criteria based on individual codons, such as ICU, have been widely used for gene optimization, our experimental results suggested that codon context is relatively more effective parameter for improving recombinant IFN-γ expression in CHO cells.
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research-A*STAR, 20 Biopolis Way #06-01, Singapore 138668, Singapore.
authors.forename: Bevan Kai-Sheng
authors.initials: BK
authors.lastname: Chung
authors.forename: Faraaz N K
authors.initials: FN
authors.lastname: Yusufi
authors.lastname: Mariati
authors.forename: Yuansheng
authors.initials: Y
authors.lastname: Yang
authors.forename: Dong-Yup
authors.initials: DY
authors.lastname: Lee
mesh_terms: D000818:Animals; D016466:CHO Cells; D003062:Codon; D006224:Cricetinae; D003412:Cricetulus; D020869:Gene Expression Profiling; D007371:Interferon-gamma / Q000235:genetics* / Q000378:metabolism; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D011994:Recombinant Proteins; D007371:Interferon-gamma
keywords: Chinese hamster ovary cells; Codon context; Codon optimization; Interferon-gamma; Recombinant protein production; Synthetic gene design