Makarow M, Sareneva H, von Bonsdorff C H
J Biol Chem. 1987 Feb 5;262(4):1836-41.
Vesicular stomatitis virus (VSV) was associated at low pH with Saccharomyces cerevisiae spheroplasts. In the cold, the association was characterized as reversible binding to the spheroplast surface. At 37 degrees C, the association became irreversible due to fusion of the viral envelope with the yeast plasma membrane according to the following data. Proteinase K digestion degraded the viral envelope glycoprotein G but left the internal N and M proteins of VSV intact and associated with the spheroplasts. The plasma membrane could be stained by indirect immunofluorescent labeling using antiserum against VSV. By immunoelectron microscopy, no VSV particles could be detected at the spheroplast surface. Instead, the G protein could be visualized at the external aspect of the plasma membrane using specific antiserum and protein A-gold. Fusion of VSV with spheroplasts occurred below pH 4.75 at temperatures of 30-42 degrees C. It was strictly dependent on the prior removal of the yeast cell wall. The fusion process was fast, calcium-independent, and nonleaky, leaving the spheroplasts viable for at least 4 h. On the average, less than 100 VSV particles could be fused per one spheroplast. Similar data were obtained with Semliki Forest virus.
水泡性口炎病毒（VSV）在低pH值条件下与酿酒酵母原生质体相关联。在低温下，这种关联表现为与原生质体表面的可逆结合。根据以下数据，在37℃时，由于病毒包膜与酵母质膜融合，这种关联变得不可逆。蛋白酶K消化降解了病毒包膜糖蛋白G，但VSV的内部N蛋白和M蛋白保持完整并与原生质体相关联。使用抗VSV抗血清通过间接免疫荧光标记可对质膜进行染色。通过免疫电子显微镜观察，在原生质体表面未检测到VSV颗粒。相反，使用特异性抗血清和蛋白A金可在质膜外侧观察到G蛋白。在30 - 42℃、pH值低于4.75的条件下，VSV与原生质体发生融合。这严格依赖于事先去除酵母细胞壁。融合过程迅速，不依赖钙，且无泄漏，使原生质体至少存活4小时。平均而言，每个原生质体可融合少于100个VSV颗粒。用辛德毕斯病毒也获得了类似的数据。
