Receptor-mediated endocytosis using a β1
integrin-dependent internalization was considered as the primary mechanism for the initiation of mammalian
reovirus infection. Bombyx mori cypovirus (BmCPV) is a member of Reoviridae family which mainly infects the midgut epithelium of silkworm; the cell entry of BmCPV is poorly explored. In this study, co-immunoprecipitation (Co-IP), virus overlay protein binding assay (VOPBA), and BmCPV-
protein interaction on the
polyvinylidene difluoride membrane (BmCPV-PI-
PVDF) methods were employed to screen the interacting
proteins of BmCPV, and several
proteins including
integrin beta and receptor for activated
protein kinase C (RACK1) were identified as the candidate interacting
proteins for establishing the
infection of BmCPV. The infectivity of BmCPV was investigated in vivo and in vitro by RNA interference (RNAi) and antibody blocking methods, and the results showed that the infectivity of BmCPV was significantly reduced by either
small interfering RNA-mediated silencing of
integrin beta and RACK1 or antibody blocking of
integrin beta and RACK1. The expression level of
integrin beta or RACK1 is not the highest in the silkworm midgut which is a principal target tissue of BmCPV, suggesting that the molecules other than
integrin beta or RACK1 might play a key role in determining the tissue tropism of BmCPV
infection. The establishment of BmCPV
infection depends on other factors, and these factors interacted with
integrin beta and RACK1 to form receptor complex for the cell entry of BmCPV.