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).