Poliovirus RNA Is Released from the Capsid near a Twofold Symmetry Axis
- 15 January 2011
- journal article
- Published by American Society for Microbiology in Journal of Virology
- Vol. 85 (2), 776-783
- https://doi.org/10.1128/jvi.00531-10
Abstract
After recognizing and binding to its host cell, poliovirus (like other nonenveloped viruses) faces the challenge of translocating its genome across a cellular membrane and into the cytoplasm. To avoid entanglement with the capsid, the RNA must exit via a single site on the virion surface. However, the mechanism by which a single site is selected (from among 60 equivalents) is unknown; and until now, even its location on the virion surface has been controversial. To help to elucidate the mechanism of infection, we have used single-particle cryo-electron microscopy and tomography to reconstruct conformationally altered intermediates that are formed by the poliovirion at various stages of the poliovirus infection process. Recently, we reported icosahedrally symmetric structures for two forms of the end-state 80S empty capsid particle. Surprisingly, RNA was frequently visible near the capsid; and in a subset of the virions, RNA was seen on both the inside and outside of the capsid, caught in the act of exiting. To visualize RNA exiting, we have now determined asymmetric reconstructions from that subset, using both single-particle cryo-electron microscopy and cryo-electron tomographic methods, producing independent reconstructions at ∼50-Å resolution. Contrary to predictions in the literature, the footprint of RNA on the capsid surface is located close to a viral 2-fold axis, covering a slot-shaped area of reduced density that is present in both of the symmetrized 80S reconstructions and which extends by about 20 Å away from the 2-fold axis toward each neighboring 5-fold axis.Keywords
This publication has 63 references indexed in Scilit:
- Catching a Virus in the Act of RNA Release: a Novel Poliovirus Uncoating Intermediate Characterized by Cryo-Electron MicroscopyJournal of Virology, 2010
- PicornavirusesPublished by Springer Science and Business Media LLC ,2010
- Crystal structure of CD155 and electron microscopic studies of its complexes with poliovirusesProceedings of the National Academy of Sciences of the United States of America, 2008
- Post-imaging fiducial markers aid in the orientation determination of complexes with mixed or unknown symmetryJournal of Structural Biology, 2008
- DNA Poised for Release in Bacteriophage ø29Structure, 2008
- Single particle cryoelectron tomography characterization of the structure and structural variability of poliovirus–receptor–membrane complex at 30Å resolutionJournal of Structural Biology, 2007
- Poliovirus entry into human brain microvascular cells requires receptor-induced activation of SHP-2The EMBO Journal, 2007
- Visualization of the herpes simplex virus portal in situ by cryo-electron tomographyVirology, 2007
- SPIDER and WEB: Processing and Visualization of Images in 3D Electron Microscopy and Related FieldsJournal of Structural Biology, 1996
- Computer Visualization of Three-Dimensional Image Data Using IMODJournal of Structural Biology, 1996