痘苗病毒VGF细胞膜外结构域在真核及原核细胞中的表达

目的为了进一步探索ＶＧＦ的生物学功能方法分别构建了痘苗病毒天坛株生长因子（Ｖａｃｃｉｎｉａｇｒｏｗｔｈｆａｃｔｏｒ，ＶＧＦ）基因细胞膜外结构域（ＶＧＦｓｌ）的真核及原核表达系统，在相应的细胞中获得了单独表达（真核）和融合表达（原核）。结果初步纯化的ＶＧＦｓｌ表达产物能够与上皮生长因子（ＥＧＦ）的受体结合，并刺激受体中酪氨酸残基发生磷酸化反应。与ＥＧＦ相比，ＶＧＦｓｌ表达产物刺激ＥＧＦ受体自身磷酸化的能力更强。结论上述结果为ＶＧＦ在病毒感染过程中的作用以及ＶＧＦ作为新型多肽类药物的研究提供了有价值的线索。

Expression of secreted legand domain of vaccinia growth factor encoded by vaccinia virus strain Tian Tan in E.coli and insect cells

Vaccinia virus growth factor (VGF) is encoded by an early gene of vaccinia virus strain TianTan located near the border between the terminal inverted repeats and the internal region of the viral genome as one copy. Its relationship to members of epidermal growth factor superfamily was discovered when computer searches of protein sequences revealed that VGF has strong sequence homology with these growth factors. To further get insight into the biological activity of VGF, we cloned and expressed the secreted ligand domain of VGF (VGFsl) encoded by vaccinia virus strain TianTan in E. coli and insect cells. The results of biological activity test indicated that expressed products is capable of binding to the EGF receptor, and stimulating EGF receptor tyrosin autophosphorylation to a level greater than that of EGF.