THE E1 GLYCOPROTEIN OF AN AVIAN CORONAVIRUS IS TARGETED TO THE CIS GOLGI-COMPLEX
THE E1 GLYCOPROTEIN OF AN AVIAN CORONAVIRUS IS TARGETED TO THE CIS GOLGI-COMPLEX
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DOI：
10.1073/pnas.87.18.6944
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发表时间：
1990-09-01
影响因子：
11.1
通讯作者：
FARQUHAR, MG
中科院分区：
文献类型：
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作者：
MACHAMER, CE;MENTONE, SA;FARQUHAR, MG
以前有报道称，禽冠状病毒的E1蛋白质在表达来自克隆cDNA的蛋白质的COS细胞中靶向于胞核区域，这表明该蛋白质包含靶向于高尔基复合体的信息。细胞内靶向需要三个跨膜结构域中的第一个，因为缺乏该结构域的突变体E1（Δ m1，2）被递送至质膜。我们已经使用免疫电子显微镜定位野生型E1蛋白质内的高尔基体元件的COS细胞和AtT-20细胞表达这些蛋白质从重组牛痘载体。通过免疫过氧化物酶和免疫金标记，野生型E1蛋白被定位于一个或两个位于高尔基体堆栈的一侧，可以确定为在AtT-20细胞的顺式侧的池。与此相反，突变体E1蛋白检测到在所有池跨堆栈以及在质膜。当E1蛋白进行免疫沉淀，并进行消化与糖苷内切酶H，大多数的野生型E1糖蛋白是糖苷内切酶H敏感，而大多数的突变体E1被加工成糖苷内切酶H-抗性，含有聚乳糖胺聚糖的形式。研究结果表明，野生型E1蛋白是专门针对顺式高尔基体池，并与假设的第一个跨膜结构域是需要针对顺式高尔基体是一致的。
It was previously reported that the E1 protein of an avian coronavirus was targeted to the juxtanuclear region in COS cells expressing the protein from cloned cDNA, suggesting that the protein contains information for targeting to the Golgi complex. The first of three membrane-spanning domains was required for intracellular targeting, because a mutant E1 (.DELTA.m1,2) lacking this domain was delivered to the plasma membrane. We have used immunoelectron microscopy to localize the wild-type E1 protein within Golgi elements of COS cells and AtT-20 cells expressing these proteins from recombinant vaccinia vectors. By immunoperoxidase and immunogold labeling, the wild-type E1 protein was localized to one or two cisternae located on one side of the Golgi stack that could be identified as the cis side in AtT-20 cells. In contrast, the mutant E1 protein was detected in all cisternae across the stack as well as at the plasma membrane. When the E1 proteins were immunoprecipitated and subjected to digestion with endoglycosidase H, the majority of the wild-type E1 glycoprotein was endoglycosidase H sensitive, whereas the majority of the mutant E1 was processed to an endoglycosidase H-resistant, polylactosaminoglycan-containing form. The findings indicate that the wild-type E1 protein is specifically targeted to cis Golgi cisternae and are consistent with the assumption that the first membrane-spanning domain is required for targeting to the cis Golgi.