传染性支气管炎病毒S1蛋白在Vero细胞的表达与分布

将传染性支气管炎病毒（IBV）ZJ971 S1基因亚克隆到绿色荧光蛋白（GFP）表达载体pEGFP—C2中，成功构建重组表达质粒pEGFP—ZJ971-S1。重组质粒在脂质体的介导下转染Vero细胞，借助荧光显微镜在转染后4h观察到S1—GFP融合蛋白的瞬时表达。免疫细胞化学染色（ICC）结果显示，抗ZJ971 S1D蛋白单克隆抗体和鸡抗IBVZJ971全病毒血清特异性识别了S1基因转染细胞，表明S1蛋白在Vero细胞中得到有效表达。荧光显微镜观察和ICC均表明，S1表达蛋白主要分布在转染细胞的胞浆内，而胞核中未见分布，提示IBVS1蛋白内可能存在与病毒装配相关的细胞定位信号。

Expression and distribution of S1 protein of infectious bronchitis virus in Vero cells

S1 gene of infectious bronchitis virus (IBV) strain ZJ971 was subcloned into an expression vector pEGFP-C2 carrying GFP reporter gene and a recombinant plasmid, designated as pEGFP-ZJ971-S1, was successfully constructed. Vero cells were transfected with the recombinant plasmid by liposome and finally S1-GFP fusion protein was transiently expressed 4 h post-tranfection. Immunocytochemical staining showed that monoclonal antibodies against IBV ZJ971 S1 protein and chick anti-IBV serum specifically recognized S1 protein expressed in Vero cells. Fluorescence observation for Vero cells expressing GFP-fused S1 protein and ICC both confirmed that the S1-GFP was found to mainly distribute in the cytoplasma but not in the nucleus of S1-transfected Vero cells, suggesting that intracellular targeting signal involved in viral assembly may exist within IBV S1 protein.