Institute of Biotechnology, University of Helsinki, 00790, Helsinki, Finland.
Proc Natl Acad Sci U S A. 2011 Nov 1;108(44):18085-90. doi: 10.1073/pnas.1105770108. Epub 2011 Oct 24.
Measles virus is a highly infectious, enveloped, pleomorphic virus. We combined electron cryotomography with subvolume averaging and immunosorbent electron microscopy to characterize the 3D ultrastructure of the virion. We show that the matrix protein forms helices coating the helical ribonucleocapsid rather than coating the inner leaflet of the membrane, as previously thought. The ribonucleocapsid is folded into tight bundles through matrix-matrix interactions. The implications for virus assembly are that the matrix already tightly interacts with the ribonucleocapsid in the cytoplasm, providing a structural basis for the previously observed regulation of RNA transcription by the matrix protein. Next, the matrix-covered ribonucleocapsids are transported to the plasma membrane, where the matrix interacts with the envelope glycoproteins during budding. These results are relevant to the nucleocapsid organization and budding of other paramyxoviruses, where isolated matrix has been observed to form helices.
麻疹病毒是一种高度传染性、包膜、多形性病毒。我们将电子晶体断层扫描与子体积平均法和免疫吸附电子显微镜相结合，以描绘病毒粒子的 3D 超微结构。我们表明，基质蛋白形成螺旋，覆盖在螺旋核糖核蛋白壳上，而不是以前认为的覆盖在膜的内叶上。核糖核蛋白通过基质-基质相互作用折叠成紧密的束。这对病毒组装的影响是，基质蛋白已经在细胞质中与核糖核蛋白紧密相互作用，为以前观察到的基质蛋白对 RNA 转录的调节提供了结构基础。接下来，覆盖基质的核糖核蛋白被运送到质膜，在那里基质蛋白在出芽过程中与包膜糖蛋白相互作用。这些结果与其他副粘病毒的核衣壳组织和出芽有关，在那里已经观察到分离的基质形成螺旋。
