为了探索家蚕核型多角体病毒(BmNPV)的包涵体衍生病毒(ODV)囊膜蛋白在病毒粒子包涵入多角体过程中的作用,选择2个ODV囊膜蛋白ODV-E25和ODV-E56作为研究对象,利用能够表达多角体蛋白的BmNPV Polh+Bac-to-Bac表达系统构建了融合表达E25-EGFP和E56-EGFP的重组病毒,在家蚕卵巢培养细胞系(BmN)中进行表达和定位分析。结果表明2种融合蛋白均在BmN细胞中成功表达,并于荧光显微镜下观察到绿色荧光主要分布在细胞核中。从感染的BmN细胞中收集纯化多角体,观察到多角体也能激发出绿色荧光,用Western blot方法进一步证实多角体中含有融合蛋白。这一现象表明当囊膜蛋白基因与外源基因融合表达时,外源融合蛋白能够进入多角体内部,推测这2种ODV囊膜蛋白不仅在病毒粒子包涵入多角体的过程中起信号引导作用,并能引导外源目的蛋白进入多角体。
In order to study the function of occlusion-derived virus (ODV) envelope protein of Bombyx mori nucleopolyhedrovirus (BmNPV) in the process of packaging virions into polyhedra,two different envelope proteins,ODV-E25 and ODV-E56,were selected for present study.BmNPV Polh + Bac-to-Bac expression system capable of expressing polyhedron protein was used to construct two recombinant viruses for fusion expression of E25-EGFP and E56-EGFP.Expression and localization analyses of these two proteins were conducted in Bombyx mori ovarian cell line (BmN) .The results showed that both fusion proteins were expressed in BmN cells successfully.Fluorescent microscopic observation showed that the fluorescence was mainly present within the nucleus.Moreover,fluorescence was also detected on polyhedra purified from BmN cells infected with the recombinant virus.Western blot analysis further confirmed that the fusion proteins were present in the polyhedra.The observation from this experiment showed that,when the envelope protein gene was fused with a foreign gene,it could cause immobilization of the foreign protein in BmNPV polyhedra.It was supposed that the two ODV envelope proteins not only function as signals for packaging virions into polyhedra,but also induce immobilization of foreign proteins in the polyhedra.