Expression of bovine Mx1 protein inhibits the replication of foot-and-mouth disease virus in BHK-21 cells

Mx proteins belonging to the dynamin superfamily of large GTPases inhibit replication of a wide range of RNA viruses. In this study, we examined whether bovine Mx1 protein could interfere with the replication of foot-and-mouth disease virus (FMDV). For this purpose we established cloned BHK-21 cells expressing bovine Mx1 protein (BM1 cells) and infected them with FMDV serotype O. Cloned BHK-21 cells expressing neomycin resistance instead of Mx1 protein (BH1 cells) and original BHK-21 cells served as negative controls. The results showed that the expression of bovine Mx1 protein reduced viral yields by 90% and levels of viral VP1 mRNA by 60%. These findings correlated with a significant reduction of viral antigen detectable in infected cells by immunofluorescent assay. These results demonstrate that bovine Mx1 protein interferes with the replication of FMDV.