hDll1ext-Fc融合蛋白的表达纯化与初步鉴定

目的获得高效表达hDll1ext-Fc融合蛋白的细胞系以及具有生物学活性的目的蛋白。方法根据已知序列设计引物,并将hDll1ext基因片段经PCR扩增,酶切后连接至pIRES2-EGFP-Fc中,挑选阳性克隆测序,将正确的重组质粒转染至CHO-S细胞,筛选高表达细胞系,利用rProtein A亲和柱纯化目的蛋白,并通过检测Notch下游信号分子Hes1的表达及双荧光素酶报告基因实验检测蛋白活性。结果构建了pIRES2-EGFP-hDll1ext-Fc真核表达载体,并筛选了高效表达hDll1ext-Fc的CHO-S细胞系,纯化得到较高纯度的融合蛋白,配合生物活性检测实验显示,可溶性的hDll1ext-Fc能够激活Hes1报告基因,并且能上调Notch下游分子Hes1的表达,证明其能够激活Notch信号通路。结论在CHO-S细胞中成功表达了hDll1ext-Fc融合蛋白,为进一步研究Delta-like-1的生物学功能奠定重要基础。

Expression,purification and preliminary identification of hDll1ext-Fc fusion protein

Objective To obtain the CHO-S cell lines expressing hDll1ext-Fc （human Delta-like-1 extracellular domain-Fc） fusion protein and the target protein with biological activity. Methods The hDll1ext gene was amplified through PCR with the primers designed according to the known sequences, then inserted into pIRES2-EGFP-Fc vector, transformed into the competent cells. The positive clones were screened for sequencing. The recombinant plasmid pIRES2-EGFP-hDll1ext-Fc was transfected into the CHO-S cells, and then the high expressed cell lines were screened and the interest protein was purified with affinity rProtein A column. The biological activity of hDll1ext-Fc was determined by Dual-Luciferase Reporter Assay and the express of Hes1 which is a downstream factor in Notch pathway. Results We obtained the eukaryotic expression vector pIRES2-EGFP-hDll1ext-Fc, high expressed cell lines and high purified hDll1ext-Fc fusion protein. The experiment of biological activity showed that soluble hDll1ext-Fc activated Hes1 reporter gene and up-regulated the expression of Hes1. Conclusion The recombinant plasmid pIRES2-EGFP-hDll1ext-Fc is constructed and the fusion protein is expressed, which lays the important foundation of further study on its biological function.