目的　在大肠埃希菌中表达乙型脑炎病毒E蛋白。方法　反转录聚合酶链反应 (PCR)扩增乙型脑炎病毒 (JEV)E蛋白基因 ,克隆入原核表达载体pET 2 8a,转化大肠埃希菌BL2 1(ED3)。经异丙基巯基半乳糖 (IPTG)诱导表达后 ,十二烷基硫酸钠 聚丙烯酰胺凝胶电泳 (SDS PAGE)和蛋白免疫印迹分析表达产物。结果　本室所保存毒株的E蛋白与已发表的序列比较 ,有 5个核苷酸改变 ,可分别导致氨基酸替代。所表达的E蛋白的相对分子质量约为 5 0 0 0 0 ,表达量约占菌体总蛋白的 35 %。结论　在大肠埃希菌中成功地表达了JEVE蛋白 ,为制备JE实验室诊断抗原和分析E蛋白基因结构与功能的关系打下了基础 Objective To express Japanese encephalitis virus E protein in Escherichia coli. Methods The E protein gene of Japanese encephalitis virus (JEV) was amplified by reverse transcription polymerase chain reaction (PCR) and cloned into prokaryotic expression vector pET 2 8a and transformed into E. coli BL21 (ED3). The expression product was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) and Western blotting after induced by isopropylmercapto galactose (IPTG). Results Compared with the published sequences, the E protein of the strain preserved in our laboratory showed five nucleotide changes, which could lead to amino acid substitutions respectively. The relative molecular mass of the expressed protein E is about 50,000, and the expression level is about 35% of the total bacterial protein. Conclusions The JEVE protein was successfully expressed in Escherichia coli and laid the foundation for the construction of JE laboratory diagnostic antigen and analysis of the relationship between E protein gene structure and function