Cell proliferation effect of human epidermal growth factor fused with trigger factor in E.coli

Abstract

The recombinant protein production in E. coli system has advantages of be inexpensive, rapid expression and high yields. However, accumulation of target protein into insoluble form in E.coli expression system requires complicated and costly denaturation and refolding strategy for recovery of the biological activity. Diverse techniques have been developed to simplify downstream process including co-expression of chaperones and secretion of proteins into periplasm or media. In order to produce recombinant protein of human epidermal growth factor (hEGF) efficiently, we synthesized the gene using the signal peptide of xylanase obtained from Bacillus subtilis CH2 because the signal peptide plays an important role in secretion of protein into periplasm or culture media. Then, a trigger factor (TF) which is one of the chaperone derived from E. coli was fused to increase the solubility. The synthesized gene was cloned into pET11-a vector and overexpressed in E. coli BL21(DE3) using IPTG. Expression analysis of hEGF-TF was conducted according to induction time. The amount of hEGF-TF in the total protein decreased, and the amount of secreted hEGF-TF increased overtime. Additionally MTT cell proliferation assay was conducted to determine the activity of hEGF-TF protein on human dermal fibroblast while comparing with commercial hEGF. It showed that the proliferative effect of hEGF-TF is higher than commercial hEGF.