目的 构建人EGF受体(EGFR)胞外域的原核表达载体并在大肠杆菌中表达,制备EGFR特异性抗体,对表达产物进行鉴定。方法 以PCR方法从克隆的EGFR胞外区cDNA中扩增编码胞外结构域L1、S1、L2(EGFR-LSL)的DNA片段,并在其3′端加入编码His6标签的序列,与pET-3c连接构建EGFR-LSL原核表达载体,在大肠杆菌中进行表达;同时以纯化的EGFRL2结构域蛋白(EGFR-L2)制备抗血清,以此抗血清鉴定表达产物。结果 EGFR-LSL在大肠杆菌BL21(DE3)中获得高效表达,抗His6抗体免疫印迹分析表明,表达产物全部以包涵体形式存在,通过Ni2^+.NTA柱上复性获得纯化的可溶性EGFR-LSL蛋白;免疫印迹分析表明,EGFR-LSL与小鼠抗EGFR-L2抗血清具有高特异性反应。结论 从大肠杆菌中获得具有特异抗原性的可溶性EGFR-LSL蛋白。
Objective To construct a prokaryotic expression vector for the extracellular domain of EGFR and to identify the its expression product in Escherichia coli ( E. coli) with specific antisenan against EGFR-L2 domain. Methods DNA fragment, encoding the extracellular domains L1, S1, and L2 of EGFR (EGFR-LSL), containing a His6-tag at the carboxyl terminus, was amplified by PCR from the cDNA of EGFR extracellular region, and then was inserted into pET-3c to construct the prokaryotic expression vector for EGFR-LSL. Antisenan was prepared with the purified EGFR L2 domain (EGFR-L2) and was used to identify the EGFR-LSL. Results EGFR-LSL was highly expressed in E. coli BL21(DE3) strain and was only present in the inclusion body as revealed by immunoblotting analysis with anti-His6 antibody. Soluble EGFR-LSL was purified through on-colunm renaturing of denatured EGFR-LSL bound to Ni26+ -NTA. Furthermore, EGFR-LSL had highly spe- cific reactivity with mouse anti-EGFR-L2 antiserum. Conclusion The soluble EGFR-LSL obtained from E. coli possesses specific antigenicity.