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

The expression of the fruit bat tetherin gene was initially assessed by a BLASTn search within the transcriptome of an Australian fruit bat, the Black flying fox, Pteropus alecto, using the human tetherin amino acid sequence as the search query. We identified 30 contigs matching the query (lowest E-value = 9.21 x 10 -23 ). A single P. alecto homolog of tetherin, herein described as isoform A, homologous to human l-tetherin and the predicted X1 isoform (GenBank: XM_006904279), was identified. P. alecto Tetherin isoform A has a low level of primary amino acid sequence conservation (37%) compared Results 8 to human l-tetherin ( Figure 2A ) and other mammalian (28 -47%) tetherin sequences homologous to human l-tetherin ( Figure 2B ). Despite the low amino acid sequence identity, the predicted secondary structures and protein domains are largely conserved between bats and other mammals ( Figure 2B ), with all tetherin proteins containing the cytoplasmic (CD), transmembrane (TM), extracellular domains (ED), and the posttranslationally cleaved GPI-anchor signal peptide (GSP). An exception to this is the tetherin B of sheep, which does not contain the GSP domain.