核蛋白丝的自封盖保护新城疫病毒基因组。

Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, China.

National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.

Elife. 2019 Jul 10;8:e45057. doi: 10.7554/eLife.45057.

Non-segmented negative-strand RNA viruses, such as measles, ebola and Newcastle disease viruses (NDV), encapsidate viral genomic RNAs into helical nucleocapsids, which serve as the template for viral replication and transcription. Here, the clam-shaped nucleocapsid structure, where the NDV viral genome is sequestered, was determined at 4.8 Å resolution by cryo-electron microscopy. The clam-shaped structure is composed of two single-turn spirals packed in a back-to-back mode. This tightly packed structure functions as a seed for the assembly of a nucleocapsid from both directions, facilitating the growth of double-headed filaments with two separate RNA strings inside. Disruption of this structure by mutations in its loop interface yielded a single-headed unfunctional filament.

无分段负链 RNA 病毒，如麻疹、埃博拉病毒和新城疫病毒（NDV），将病毒基因组 RNA 包裹到螺旋核衣壳中，核衣壳作为病毒复制和转录的模板。在这里，通过冷冻电镜以 4.8Å 的分辨率确定了蛤壳状的核衣壳结构，其中封闭了 NDV 病毒基因组。蛤壳状结构由两个单匝螺旋以背对背的方式包装而成。这种紧密堆积的结构充当了来自两个方向组装核衣壳的种子，有利于形成具有内部两个单独 RNA 链的双头丝。通过突变其环接口破坏这种结构，产生了单头无功能丝。