Structural dissection of Ebola virus and its assembly determinants using cryo-electron tomography
Structural dissection of Ebola virus and its assembly determinants using cryo-electron tomography
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DOI：
10.1073/pnas.1120453109
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发表时间：
2012-03-13
影响因子：
11.1
通讯作者：
Briggs, John A. G.
中科院分区：
文献类型：
--
作者：
Bharat, Tanmay A. M.;Noda, Takeshi;Briggs, John A. G.
埃博拉病毒是一种高致病性丝状病毒，引起严重的出血热，死亡率高。它组装异源、丝状、包膜病毒颗粒，所述病毒颗粒含有包装在螺旋核衣壳（NC）内的负义单链RNA基因组。我们已经使用冷冻电子显微镜和断层扫描来可视化埃博拉病毒颗粒，以及埃博拉病毒样颗粒，在接近原生状态的三维空间中。病毒粒子内的NC形成左手螺旋，其具有由VP 24和VP 35组成的突出臂装饰的内核蛋白层。与密切相关的马尔堡病毒的比较表明，核蛋白的N-末端区域决定了埃博拉病毒NC的内径，而RNA基因组决定了其长度。核蛋白与RNA的结合可以组装成松散卷曲的NC样结构;松散卷曲可以通过病毒基质蛋白VP 40与核蛋白的C末端的结合而浓缩，并通过VP 24和VP 35与核蛋白的交替拷贝的结合而硬化。四种蛋白质（NP，VP 24，VP 35和VP 40）是必要的，足以介导组装的NC的结构，对称性，变异性和灵活性与埃博拉病毒颗粒从感染的细胞释放的区别。这些数据共同提供了埃博拉病毒的结构和架构描述，并定义了病毒蛋白在其结构和组装中的作用。
Ebola virus is a highly pathogenic filovirus causing severe hemorrhagic fever with high mortality rates. It assembles heterogenous, filamentous, enveloped virus particles containing a negative-sense, single-stranded RNA genome packaged within a helical nucleocapsid (NC). We have used cryo-electron microscopy and tomography to visualize Ebola virus particles, as well as Ebola virus-like particles, in three dimensions in a near-native state. The NC within the virion forms a left-handed helix with an inner nucleoprotein layer decorated with protruding arms composed of VP24 and VP35. A comparison with the closely related Marburg virus shows that the N-terminal region of nucleoprotein defines the inner diameter of the Ebola virus NC, whereas the RNA genome defines its length. Binding of the nucleoprotein to RNA can assemble a loosely coiled NC-like structure; the loose coil can be condensed by binding of the viral matrix protein VP40 to the C terminus of the nucleoprotein, and rigidified by binding of VP24 and VP35 to alternate copies of the nucleoprotein. Four proteins (NP, VP24, VP35, and VP40) are necessary and sufficient to mediate assembly of an NC with structure, symmetry, variability, and flexibility indistinguishable from that in Ebola virus particles released from infected cells. Together these data provide a structural and architectural description of Ebola virus and define the roles of viral proteins in its structure and assembly.