Expression of biologically active human insulin-like growth factor 1 in Arabidopsis thaliana seeds via oleosin fusion technology

Novel protein expression in plant-based systems has become an important tool in producing and studying therapeutic proteins. Among many plant-based systems developed so far, oleosin fusion technology is one of the most cost-effective and convenient methods. In this study, an important therapeutic protein, human insulin-like growth factor 1 (hIGF-1), was expressed in Arabidopsis thaliana seeds via this technology. The plant bias codon usage-optimized hIGF-1 gene was fused to the C-terminal of A. thaliana 18.5 kDa oleosin gene, and the 2011 International Union of Biochemistry and Molecular Biology, Inc. fusion gene driven by an oleosin promoter was transferred into A. thaliana ecotype Col-o. The accumulation of oleosin hIGF-1 fusion protein in transgenic seeds was up to 0.75% of total seed protein (TSP) and the expression level of hIGF-1 was 0.17% of the TSP, which was eight times higher than previously reported using other plant-based hIGF-1 production systems. The biological activity of the hIGF-1 as an oleosin hIGF-1 fusion protein in vitro was demonstrated by using human SH-SY5Y neuroblastoma cells. (C) 2011 International Union of Biochemistry and Molecular Biology, Inc. Volume 58, Number 3, May/June 2011, Pages 139-146. E-mail: kxtang1@yahoo.com