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

Intriguingly, one of the non-transmembrane domain-associated sites under strong positive selection across tetherin from bats is located in the middle of the extracellular domain. This is the site that distinguishes the P. alecto tetherin isoforms A and B, with the 7 AA exclusion at this location in isoform B. This suggests that the expression of P. alecto tetherin isoform B as an alternative to isoform A, and possibly also M. macropus tetherin B and E, which differ from tetherin A through a large 60 AA deletion in the same region, is to express a form of tetherin that does not include a sequence motif that appears to be a possible site of viral antagonism. This hypothesis may be supported by future experiments aimed at identifying viral antagonists of P. alecto tetherin isoform A that are ineffective against isoform B.