瞬时基因表达可溶性的VEGFR2: I-IV

通过RT-PCR的方法从三个月的流产绒毛组织中克隆目的基因VEGFR2 (Vascular endothelial growth factor receptor 2, 血管内皮细胞生长因子受体2) 胞外I-IV区, 连接到真核表达载体上构建了重组表达载体。首先在无血清悬浮培养的HEK293细胞中, 使用报告基因GFP(Green fluorescence protein, 绿色荧光蛋白)优化转染条件, 发现在转染时DNA: PEI=1:2 (W/W)、1.5 mg DNA/106 cells及开始转染4 h内使用无血清、摇床(120 r/min)时可以达到最佳的转染效率和细胞数量。在确定转染条件之后, 将构建的表达载体分别在HEK293细胞、COS-7细胞和CHO-K1细胞中进行瞬时转染表达, 结果发现仅在CHO-K1细胞的培养上清中检测到目的蛋白的表达。瞬时转染CHO-K1细胞至总体积约为1.5 L, 由于目的蛋白的羧基端有8-His标签, 通过Ni2+-IDA柱纯化得到5 mg左右的目的蛋白。

Transient Gene Expression of Soluble VEGFR2: I-IV

The extracelluar domain I-IV of target gene VEGFR2 (Vascular endothelial growth factor receptor 2) was cloned from villus of trimester abortion by RT-PCR, and linked to the expression vectors. Then, the transfection conditions were optimized in serum-free suspension culture HEK293 using GFP (Green fluorescence protein) as the report gene. The results showed that the optimal transfection efficiency and cell number were obtained when the ratio of foreign DNA: PEI= 1:2 (W/W), DNA=1.5 g /106 cells and shaking speed (120 r/min) in serum free medium in the beginning 4 hours of transfection. After optimizing the transfection conditions, the expression vector was successfully constructed for transient gene expression in HEK293, COS-7, and CHO-K1. The result shows that the target protein was only detected in CHO-K1 supernatant. Because of the C-terminal 8-His tag of target protein, target protein was subsequently purified using Ni2+-IDA and 5 mg purified protein was obtained in 1.5 L supernatant of CHOK1.