Orthomyxoviruses, such as influenza and thogotoviruses, are important human and animal pathogens. Their segmented viral RNA genomes are wrapped by viral nucleoproteins (NPs) into helical ribonucleoprotein complexes (RNPs). NP structures of several influenza viruses have been reported. However, there are still contradictory models of how orthomyxovirus RNPs are assembled. Here, we characterize the crystal structure of Thogoto virus (THOV) NP and found striking similarities to structures of influenza viral NPs, including a two-lobed domain architecture, a positively charged RNA-binding cleft, and a tail loop important for trimerization and viral transcription. A low-resolution cryo-electron tomography reconstruction of THOV RNPs elucidates a left-handed double helical assembly. By providing a model for RNP assembly of THOV, our study suggests conserved NP assembly and RNA encapsidation modes for thogoto- and influenza viruses.

正粘病毒，例如流感病毒和索戈托病毒，是重要的人类和动物病原体。它们的分段病毒RNA基因组被病毒核蛋白（NP）包裹成螺旋核糖核蛋白复合物（RNP）。几种流感病毒的 NP 结构已被报道。然而，关于正粘病毒 RNP 的组装方式仍然存在相互矛盾的模型。在这里，我们表征了 Thogoto 病毒 (THOV) NP 的晶体结构，发现其与流感病毒 NP 的结构惊人相似，包括两叶结构域结构、带正电荷的 RNA 结合裂口以及对三聚化和病毒重要的尾环。转录。 THOV RNP 的低分辨率冷冻电子断层扫描重建阐明了左手双螺旋组装。通过提供 THOV 的 RNP 组装模型，我们的研究表明 thogoto 病毒和流感病毒具有保守的 NP 组装和 RNA 衣壳化模式。