Screening And Verification Of The Receptors Of Porcine Deltacoronavirus

Deltacoronvirus(?-CoV)is a novel coronavirus which can infect animals and birds.PDCoV was first reported in 2009 in Hong Kong that can cause vomiting and watery diarrhea in pigs and seriously damage the development of pig industry.Up to now,the process of cellular entry of PDCoV is unclear.Infection is initiated by interaction of the viral particle with specific proteins on the cell surface.Therefore,identification of receptors of PDCoV not only can reveal the mechanism of PDCoV pathogenicity,but aid in development of new vaccines and antivirals and laid the foundation for the research of receptors for the ?-Co V.The receptors of coronvirus among different coronvirus are quite different.In our study,the known receptors pAPN and Sialic of porcine coronavirus were choosed to verifiy based on the existing research results and rationally deduction.The results showed that pAPN and Sialic acid had no effect on PDCoV replication in ST cells according to gene silencing,overexpression,receptor blocking and virus-neutralization assays,which brings a new reference for the study of PDCoV pathogenic molecular mechanism.Cellular entry of this enveloped virus is mediated by the large spike(S)glycoprotein has been reported.PDCoV S protein is a type I membrane glycoprotein.The ectodomain of coronavirus spike proteins can be divided into two domains with distinct functions: the N-terminal S1 subunit responsible for receptor binding and the C-terminal membrane anchored S2 domain.In order to further screen and identify the receptors of PDCoV.PDCoV can infect ST cells,which indicatet that the receptors of PDCoV were presented on the surface of ST cells,the eukaryotic expression and purification system of PDCoV-S1 protein was established in this study.We used PDCoV-S1 protein to screen host proteins by immunoprecipitation(IP)and identified by mass spectrometry(MS).We identified a novel host cell protein pHSPCB that can promote the proliferation of PDCo V in susceptible cells.The results showed that over-expression of pHSPCB promoted PDCoV replication,whereas down-regulation of pHSPCB by small interfering RNAs(siRNA)suppressed the replication of PDCoV,which indicated that pHSPCB is a beneficial factor during PDCoV infection.These results indicate that pAPN and Sialic are not receptors for PDCo V cell entry,and a novel host cell protein pHSPCB can promote the proliferation of PDCo V in ST cells,which brings a new reference for the study of PDCoV pathogenic molecular mechanism.