VP5 autocleavage is required for efficient infection by in vitro recoated aquareovirus particles.

　　Yan S, Zhang J, Guo H, Yan L, Chen Q, Zhang F, Fang Q.

      J Gen Virol. 2015 Mar 5.  doi: 10.1099/vir.0.000116.

　　Abstract

　　Grass carp reovirus (GCRV) is a member of the Aquareovirus genus in the family Reoviridae, and contains five core proteins (VP1-VP4, VP6) and two outer capsid proteins (VP5 and VP7) in its particle. Previous studies have revealed that the outer capsid proteins of reovirus are responsible for initiating infection, but the mechanism is poorly understood. Using baculovirus-expressed VP5 and VP7 to recoat purified cores, in vitro assembly of GCRV was achieved in this study. Recoated GCRV (R-GCRV) closely resembled native GCRV (N-GCRV) in particle morphology, protein composition and infectivity. Similar to N-GCRV, the infectivity of R-GCRV could be inhibited by treating cells with the weak base NH4Cl. In addition, recoated particles (VP5N42A/VP7 R-GCRV) carrying an Asn to Ala substitution at residue 42 of VP5 were no longer infectious. These results provide strong evidence that autocleavage of VP5 is critical for aquareovirus to initiate efficient infection.

    http://vir.sgmjournals.org/content/early/2015/03/05/vir.0.000116.short