Department of Bioengineering and Department of Microbiology and Immunology, James H. Clark Center, Stanford University, Stanford, CA 94305, USA.
Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Cell. 2018 Feb 22;172(5):966-978.e12. doi: 10.1016/j.cell.2018.02.009.
Ebola virus nucleoprotein (eNP) assembles into higher-ordered structures that form the viral nucleocapsid (NC) and serve as the scaffold for viral RNA synthesis. However, molecular insights into the NC assembly process are lacking. Using a hybrid approach, we characterized the NC-like assembly of eNP, identified novel regulatory elements, and described how these elements impact function. We generated a three-dimensional structure of the eNP NC-like assembly at 5.8 Å using electron cryo-microscopy and identified a new regulatory role for eNP helices α22-α23. Biochemical, biophysical, and mutational analyses revealed that inter-eNP contacts within α22-α23 are critical for viral NC assembly and regulate viral RNA synthesis. These observations suggest that the N terminus and α22-α23 of eNP function as context-dependent regulatory modules (CDRMs). Our current study provides a framework for a structural mechanism for NC-like assembly and a new therapeutic target.
埃博拉病毒核蛋白（eNP）组装成高级结构，形成病毒核衣壳（NC），并作为病毒 RNA 合成的支架。然而，NC 组装过程的分子见解仍然缺乏。我们使用混合方法，对 eNP 的 NC 样组装进行了表征，确定了新的调控元件，并描述了这些元件如何影响功能。我们使用电子 cryo 显微镜获得了 eNP NC 样组装的三维结构，分辨率为 5.8Å，并确定了 eNP 螺旋 α22-α23 的新调控作用。生化、生物物理和突变分析表明，α22-α23 内的 eNP 相互作用对于病毒 NC 组装至关重要，并调节病毒 RNA 合成。这些观察结果表明，eNP 的 N 端和 α22-α23 作为具有上下文依赖性的调节模块（CDRMs）发挥作用。我们目前的研究为 NC 样组装的结构机制和新的治疗靶点提供了框架。
