Sodeik B, Doms R W, Ericsson M, Hiller G, Machamer C E, van 't Hof W, van Meer G, Moss B, Griffiths G
Cell Biology Program, European Molecular Biology Laboratory, Heidelberg, Germany.
J Cell Biol. 1993 May;121(3):521-41. doi: 10.1083/jcb.121.3.521.
Vaccinia virus, the prototype of the Poxviridae, is a large DNA virus which replicates in the cytoplasm of the host cell. The assembly pathway of vaccinia virus displays several unique features, such as the production of two structurally distinct, infectious forms. One of these, termed intracellular naked virus (INV), remains cells associated while the other, termed extracellular enveloped virus (EEV), is released from the cell. In addition, it has long been believed that INVs acquire their lipid envelopes by a unique example of de novo membrane biogenesis. To examine the structure and assembly of vaccinia virus we have used immunoelectron microscopy using antibodies to proteins of different subcellular compartments as well as a phospholipid analysis of purified INV and EEV. Our data are not consistent with the de novo model of viral membrane synthesis but rather argue that the vaccinia virus DNA becomes enwrapped by a membrane cisterna derived from the intermediate compartment between the ER and the Golgi stacks, thus acquiring two membranes in one step. Phospholipid analysis of purified INV supports its derivation from an early biosynthetic compartment. This unique assembly process is repeated once more when the INV becomes enwrapped by an additional membrane cisterna, in agreement with earlier reports. The available data suggest that after fusion between the outer envelope and the plasma membrane, mature EEV is released from the cell.
痘苗病毒是痘病毒科的原型，是一种大型DNA病毒，在宿主细胞的细胞质中复制。痘苗病毒的组装途径表现出几个独特的特征，例如产生两种结构不同的感染性形式。其中一种称为细胞内裸病毒（INV），仍与细胞相关，而另一种称为细胞外被膜病毒（EEV），则从细胞中释放出来。此外，长期以来人们一直认为，INV通过一种独特的从头膜生物发生方式获得其脂质包膜。为了研究痘苗病毒的结构和组装，我们使用了免疫电子显微镜，用针对不同亚细胞区室蛋白质的抗体以及对纯化的INV和EEV进行磷脂分析。我们的数据与病毒膜合成的从头模型不一致，而是认为痘苗病毒DNA被源自内质网和高尔基体堆叠之间中间区室的膜池包裹，从而一步获得两层膜。对纯化的INV进行磷脂分析支持其源自早期生物合成区室。与早期报告一致，当INV被另一个膜池包裹时，这个独特的组装过程会再次重复。现有数据表明，外膜与质膜融合后，成熟的EEV从细胞中释放出来。
