Cryo-EM Structure of Influenza Virus RNA Polymerase Complex at 4.3 Å Resolution

• DOI: 10.1016/j.molcel.2014.12.031
• Publication Date: 2015-01-22T18:04:22Z
• Authors: Shenghai Chang; Dapeng Sun; Huanhuan Liang; Jia Wang; Jun Li; Lu Guo; Xiangli Wang; Chengcheng Guan; Bhargavi M. Boruah; Lingmin Yuan; Feng Feng; Mingrui Yang; Lulan Wang; Yao Wang; Justyna Wojdyla; Lanjuan Li; Jiawei Wang; Meitian Wang; Genhong Cheng; Hong-Wei Wang; Yingfang Liu
• Keywords: Models, Molecular; 0301 basic medicine; Sequence Homology, Amino Acid; Cryoelectron Microscopy; Molecular Sequence Data; Cell Biology; Orthomyxoviridae; RNA-Dependent RNA Polymerase; Cell Line; Protein Structure, Tertiary; 3. Good health; Protein Subunits; Viral Proteins; 03 medical and health sciences; HEK293 Cells; Imaging, Three-Dimensional; Mutation; Animals; Humans; Amino Acid Sequence; Protein Multimerization; Protein Structure, Quaternary; Molecular Biology

Replication and transcription of influenza virus genome mainly depend on its RNA-dependent RNA polymerase (RdRP), composed of the PA, PB1, and PB2 subunits. Although extensively studied, the underlying mechanism of the RdRP complex is still unclear. Here we report the biochemical characterization of influenza RdRP subcomplex comprising PA, PB1, and N terminus of PB2, which exist as dimer in solution and can assemble into a tetramer state, regulated by vRNA promoter. Using single-particle cryo-electron microscopy, we have reconstructed the RdRP tetramer complex at 4.3 Å, highlighting the assembly and interfaces between monomers within the tetrameric structure. The individual RdRP subcomplex contains all the characterized motifs and appears as a cage-like structure. High-throughput mutagenesis profiling revealed that residues involved in the oligomer state formation are critical for viral life cycle. Our results lay a solid base for understanding the mechanism of replication of influenza and other negative-stranded RNA viruses.