National Natural Science Foundation of China (NSFC)
31730023
中国
National Natural Science Foundation of China (NSFC)
31521002
中国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2022 タイトル: In situ structures of polymerase complex of mammalian reovirus illuminate RdRp activation and transcription regulation. 著者: Keyan Bao / Xueli Zhang / Dongyu Li / Wei Sun / Zhenzhao Sun / Jingfei Wang / Ping Zhu / 要旨: Mammalian reovirus (reovirus) is a multilayered, turreted member of characterized by transcription of dsRNA genome within the innermost capsid shell. Here, we present high-resolution in situ ...Mammalian reovirus (reovirus) is a multilayered, turreted member of characterized by transcription of dsRNA genome within the innermost capsid shell. Here, we present high-resolution in situ structures of reovirus transcriptase complex in an intact double-layered virion, and in the uncoated single-layered core particles in the unloaded, reloaded, pre-elongation, and elongation states, respectively, obtained by cryo-electron microscopy and sub-particle reconstructions. At the template entry of RNA-dependent RNA polymerase (RdRp), the RNA-loading region gets flexible after uncoating resulting in the unloading of terminal genomic RNA and inactivity of transcription. However, upon adding transcriptional substrates, the RNA-loading region is recovered leading the RNAs loaded again. The priming loop in RdRp was found to play a critical role in regulating transcription, which hinders the elongation of transcript in virion and triggers the rearrangement of RdRp C-terminal domain (CTD) during elongation, resulting in splitting of template-transcript hybrid and opening of transcript exit. With the integration of these structures, a transcriptional model of reovirus with five states is proposed. Our structures illuminate the RdRp activation and regulation of the multilayered turreted reovirus.