Soluble Expression of Recombinant Human Ciliary Neurotrophic Factor in E.coli Using Lactose as Inducer

Objective To express recombinant human ciliary neurotrophic factor(rhCNTF)in E.coli BL-TCS,in a soluble form,using lactose as inducer instead of IPTG,and optimize the condition for expression.Methods Induce the expression of rhCNTF in E.coli BL-TCS with various concentrations of lactose at different temperatures for 9 h,using 0.5 mmol/L IPTG as control.Compare the growth of bacteria,the consummation of lactose and the expression of target protein.Results All the A_(600) values of bacteria induced by lactose were significantly higher than that by IPTG and increased with the increasing lactose concentration.The rhCNTF under induction of lactose was mainly expressed in a soluble form,and the expression level was not less than that under induction of IPTG.The condition for expression was optimized as incubation at 25℃ for 6 h under induction of 2% lactose.Conclusion Lactose might be used as an inducer of expression of rhCNTF in E.coli instead of IPTG.