Leavitt R, Schlesinger S, Kornfeld S
J Biol Chem. 1977 Dec 25;252(24):9018-23.
Tunicamycin, an antibiotic which prevents the glycosylation of newly synthesized proteins, inhibits the replication of both vesicular stomatitis virus and Sindbis virus. In tunicamycin-treated infected cells, all of the viral proteins are synthesized but the glycoproteins are devoid of carbohydrate. The nonglycosylated glycoproteins could not be detected on the outside of the plasma membrane by lactoperoxidase labeling, indirect immunofluorescence staining, or chymotrypsin treatment of intact cells, whereas the glycosylated glycoproteins were readily detected by all three methods. These results indicate that the bulk of the nonglycosylated glycoproteins are unable to undergo the normal migration to the cell surface. In contrast to the normal glycosylated viral glycoproteins, the nonglycosylated glycoproteins were insoluble in nonionic detergents such as Triton X-100. The nonglycosylated glycoprotein of vesicular stomatitis virus could be solubilized using a combination of 6 M guanidine hydrochloride and 0.2% Triton X-100, but precipitated when the 6 M guanidine was removed by dialysis. These results suggest that the lack of carbohydrate alters the properties of the glycoproteins, which may explain their impaired mobility through the intracellular membranous system.
衣霉素是一种能阻止新合成蛋白质糖基化的抗生素，它可抑制水疱性口炎病毒和辛德毕斯病毒的复制。在用衣霉素处理的受感染细胞中，所有病毒蛋白都能合成，但糖蛋白不含碳水化合物。通过乳过氧化物酶标记、间接免疫荧光染色或对完整细胞进行胰凝乳蛋白酶处理，在质膜外表面均检测不到未糖基化的糖蛋白，而通过这三种方法都能轻易检测到糖基化的糖蛋白。这些结果表明，大量未糖基化的糖蛋白无法正常迁移到细胞表面。与正常糖基化的病毒糖蛋白不同，未糖基化的糖蛋白不溶于非离子去污剂，如 Triton X - 100。水疱性口炎病毒的未糖基化糖蛋白可使用 6M 盐酸胍和 0.2% Triton X - 100 的组合进行溶解，但通过透析去除 6M 胍后会沉淀。这些结果表明，碳水化合物的缺失改变了糖蛋白的性质，这可能解释了它们在细胞内膜系统中迁移受损的原因。
