7YF0

In situ structure of polymerase complex of mammalian reovirus in the core

This is a non-PDB format compatible entry.

Summary for 7YF0

• Entry DOI: 10.2210/pdb7yf0/pdb
• EMDB information: 33780
• Descriptor: RNA helicase, Lambda-2 protein, RNA-directed RNA polymerase, ... (5 entities in total)
• Functional Keywords: mammalian reovirus, cryo-em, rna dependent rna polymerase, transcription, viral protein
• Biological source: Mammalian orthoreovirus 3; More
• Total number of polymer chains: 22
• Total formula weight: 3073201.73

Authors

Bao, K.Y.,Zhang, X.L.,Li, D.Y.,Zhu, P. (deposition date: 2022-07-07, release date: 2023-03-29)

Primary citation

Bao, K.,Zhang, X.,Li, D.,Sun, W.,Sun, Z.,Wang, J.,Zhu, P.
In situ structures of polymerase complex of mammalian reovirus illuminate RdRp activation and transcription regulation.
Proc.Natl.Acad.Sci.USA, 119:e2203054119-e2203054119, 2022

PubMed Abstract: 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.

PubMed: 36469786
DOI: 10.1073/pnas.2203054119

Experimental method

ELECTRON MICROSCOPY (3.4 Å)