Characterization of porcine tripartite motif genes as host restriction factors against PRRSV and PEDV infection.

Members of the tripartite motif (TRIM) family are the important effectors of the innate immune response against viral infections. However, it is still unknown whether porcine TRIM (pTRIM) genes may restrict the infection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV). In this study, we firstly defined the entire pTRIM family. Fifty-seven pTRIMs were classified into 12 sub-families (C-I to C-XII) based on variable C-terminus, and 17 out of them were identified as positively selected genes. Nine pTRIMs were identified as the IFN-stimulated genes in IFN-β treated porcine alveolar macrophages (PAMs). Twelve pTRIMs were regulated in PRRSV or PEDV-infected PAMs, respectively. The mRNA expression of the implicated restriction factors (pTRIM5, 14, 21, 25 and 38) was detectable in all swine tissues studied, with the high expression in the spleen and lung tissues. These results firstly present the comprehensive characterization of pTRIM genes, and suggest the pTRIM5, 14, 21, 25, and 38 genes as the implicated host restriction factors against PRRSV and PEDV infection, which provide a basis to further study the functions of pTRIMs and the mechanism by which pTRIMs may act during viral infection.