Katz E, Wolffe E J, Moss B
Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0445, USA.
J Virol. 1997 Apr;71(4):3178-87. doi: 10.1128/JVI.71.4.3178-3187.1997.
The outer envelope of the extracellular form of vaccinia virus (EEV) is derived from the Golgi membrane and contains at least six viral proteins. Transfection studies indicated that the EEV protein encoded by the B5R gene associates with Golgi membranes when synthesized in the absence of other viral products. A domain swapping strategy was then used to investigate the possibility that the B5R protein contains an EEV targeting signal. We constructed chimeric genes encoding the human immunodeficiency virus (HIV) type 1 glycoprotein with the cytoplasmic and transmembrane domains replaced by the corresponding 42-amino-acid C-terminal segment of the B5R protein. Recombinant vaccinia viruses that stably express a chimeric B5R-HIV protein or a control HIV envelope protein with the original cytoplasmic and transmembrane domains were isolated. Cells infected with recombinant vaccinia viruses that expressed either the unmodified or the chimeric HIV envelope protein formed syncytia with cells expressing the CD4 receptor for HIV. However, biochemical and microscopic studies demonstrated that the HIV envelope proteins with the B5R cytoplasmic and transmembrane domains were preferentially targeted to the EEV. These data are consistent with the presence of EEV localization signals in the cytoplasmic and transmembrane domains of the B5R protein.
痘苗病毒细胞外形式（EEV）的外膜源自高尔基体膜，且包含至少六种病毒蛋白。转染研究表明，在没有其他病毒产物的情况下合成时，由B5R基因编码的EEV蛋白会与高尔基体膜结合。随后采用结构域交换策略来研究B5R蛋白是否含有EEV靶向信号。我们构建了嵌合基因，其编码的人类免疫缺陷病毒（HIV）1型糖蛋白的胞质和跨膜结构域被B5R蛋白相应的42个氨基酸的C末端片段取代。分离出稳定表达嵌合B5R - HIV蛋白或具有原始胞质和跨膜结构域的对照HIV包膜蛋白的重组痘苗病毒。感染了表达未修饰或嵌合HIV包膜蛋白的重组痘苗病毒的细胞，会与表达HIV的CD4受体的细胞形成多核巨细胞。然而，生化和显微镜研究表明，具有B5R胞质和跨膜结构域的HIV包膜蛋白优先靶向EEV。这些数据与B5R蛋白的胞质和跨膜结构域中存在EEV定位信号一致。
