Coronavirus-infected cells contain double-membrane vesicles (DMVs) that are key for viral RNA replication and transcription, perforated by hexameric pores connecting the vesicular lumen to the cytoplasm. How pores form and traverse two membranes, and how DMVs organize RNA synthesis, is unknown. Using structure prediction and functional assays, we show that the nonstructural viral membrane protein nsp4 is the key pore organizer, spanning the double membrane and forming most of the pore lining. Nsp4 interacts with nsp3 on the cytoplasmic side and with the viral replicase inside the DMV. Newly synthesized mRNAs exit the DMV into the cytoplasm, passing through a narrow ring of conserved nsp4 residues. Steric constraints imposed by the ring predict that modified nucleobases block mRNA transit, resulting in broad-spectrum anticoronaviral activity.

中文翻译：

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冠状病毒孔-复制酶复合物将 RNA 合成和从双膜囊泡输出联系起来


冠状病毒感染的细胞包含双膜囊泡 （DMV），这是病毒 RNA 复制和转录的关键，由连接囊泡腔和细胞质的六聚体孔穿孔。孔如何形成和穿过两个膜，以及 DMV 如何组织 RNA 合成，尚不清楚。使用结构预测和功能测定，我们表明非结构性病毒膜蛋白 nsp4 是关键的孔组织者，跨越双膜并形成大部分孔衬里。Nsp4 与细胞质侧的 nsp3 以及 DMV 内的病毒复制酶相互作用。新合成的 mRNA 离开 DMV 进入细胞质，穿过一个由保守的 nsp4 残基组成的窄环。环施加的空间限制预示着修饰的核碱基阻断 mRNA 转运，导致广谱抗冠状病毒活性。