Grass carp reovirus outer capsid proteins VP5 and VP7 interact in vitro.

Grass carp reovirus (GCRV) causes viral hemorrhagic disease in cultured grass carp. However, there is no effective means of controlling GCRV. Previous studies have shown, by cryoelectron microscopy, that the outer capsid of GCRV is composed of 200 trimers of VP5-VP7 heterodimers. However, confirmation of this interaction between VP5 and VP7 through molecular biochemistry is still lacking. This study characterized the interactions between VP5 and VP7 in vitro. VP5 was shown to interact with VP7 in a commercial yeast-two-hybrid screen. A dot-blot overlay assay was used to show that VP7 binding to VP5 was dose-dependent. Finally, a yeast-two-hybrid approach confirmed interactions between full-length and truncated forms of VP5 and VP7. In conclusion, our results indicate that VP5 and VP7 interact directly in vitro.