The Structure of Orthoreoviruses
Kelly A. Dryden, Kevin M. Coombs and Mark Yeager
from: Segmented Double-stranded RNA Viruses: Structure and Molecular Biology (Edited by: John T. Patton). Caister Academic Press, U.K. (2008)
The orthoreoviruses (reoviruses) are the prototypic members of the virus Reoviridae family, and representative of the turreted members, which comprise about half the genera. Like other members of the family, the reoviruses are non-enveloped and characterized by concentric capsid shells that encapsidate a segmented dsRNA genome. In particular, reovirus has eight structural proteins and ten segments of dsRNA. A series of uncoating steps and conformational changes accompany cell entry and replication. High-resolution structures are known for almost all of the proteins of mammalian reovirus (MRV), which is the best-studied genotype. Electron cryo-microscopy (cryoEM) and X-ray crystallography have provided a wealth of structural information about two specific MRV strains, type 1 Lang (T1L) and type 3 Dearing (T3D). This review describes the icosahedral structures of intact virions, infectious subviral particles that bind to cell surface receptors and core particles, which mediate RNA transcription. The size, shape, stoichiometry, interactions and atomic structures of the constituent proteins are described, as well as their functional properties. Such structural details about the individual proteins and the assembled particles are essential for a complete understanding of how the multiple proteins and genomic segments interact and participate in morphogenesis and infection read more ...