乳糖诱导重组鸡γ干扰素基因在大肠杆菌中的表达

Expression of Chicken Interferon-γ in Recombinant Strain E.coli BL21(DE3) Induced by Lactose

本文考察了乳糖代替IPTG诱导鸡γ干扰素(ChIFN-γ)在重组大肠杆菌BL21(DE3)中表达的可行性。分别对乳糖作为诱导剂时的诱导时机、乳糖浓度、诱导持续时间和添加方式等方面进行了分析,并在最优诱导条件下与IPTG诱导进行比较。结果表明,工程菌在对数生长中后期(OD600为1.5)添加终浓度为2g/L的乳糖诱导7h对蛋白的表达和菌体量最为有利。由于乳糖本身可作为碳源被菌体利用,分批流加乳糖效果优于一次性添加。与IPTG诱导相比,乳糖诱导的蛋白表达量为29.8%,稍低于IPTG的32.3%,诱导后蛋白表达时间也有所滞后,但收获的菌体量则显著高于IPTG诱导,约为1.21倍,显示出了乳糖作为诱导剂的自身的优势。研究结果证明乳糖可以作为诱导剂应用于重组鸡γ干扰素的工业化生产,同时也为其它重组基因工程药物的生产提供了有益的参考和借鉴。

The feasibility of expression of chicken interferon-γ in recombinant strain E.coli BL21（DE3） induced by lactose instead of IPTG was tested. The main factors of induction, such as the optimal time of induction, concentrations of the inducer （lactose）, the mode of addition and the duration of induction were analysed. The results demonstrated that the optimal condition is to add 2g/L （terminal concentration） lactose at the near end of logarithmic phase and induce 7h. It was better to add the lactose in bathes, for lactose can be used as carbon source by the bacteria. The expression of protein was 29.8% induced by lactose, little lower than 32.3% induced by IPTG, and the time of expression of the protein was later than by IPTG. However the biomass of the bacteria induced by lactose was 1.21 times much more than that induced by IPTG , showing the superiority of lactose as an inducer. The results showed that lactose could be used as inducer in industrial production of recombinant chicken interferon-γ, and gave reference to other recombinant gene-engineering drugs＇ production.