Bats Possess Unique Variants of the Antiviral Restriction Factor Tetherin

Joshua A. Hayward; Mary Tachedjian; Adam Johnson; Tamsin B. Gordon; Jie Cui; Glenn A. Marsh; Michelle L. Baker; Lin-Fa Wang; Gilda Tachedjian

We hypothesized that given the role of bats as hosts of pathogenic enveloped viruses, and the differences observed in other antiviral genes of their innate immune system (13) , that diversity might also exist in the tetherin genes of bats. Here we report that fruit bats possess a unique structural isoform in addition to the two computational predictions, tetherin isoforms X1 and X2, which were generated through the automated NCBI annotation pipeline from the published P. alecto genome (11) . We also find that vesper bats, i.e. microbats of the suborder Yangochiroptera, genus Myotis, possess at least five Introduction 5 tetherin genes, two of which contain large structural differences in the extracellular coiled-coil domain. An analysis of the tetherin genes of 27 species of bats reveal that bat tetherin has been subjected to strong positive selection, indicating these flying mammals have experienced evolutionary pressure on this important antiviral gene. Taken together, these findings indicate that bats have undergone tetherin gene expansion and diversification relative to other mammals, supporting the hypothesis of differential antiviral gene evolution in bats.