The positively selected tetherin trans-membrane region residues impact on sensitivity to HIV-1 Vpu.

<p>(A) Co-expression of HIV-1 plasmids alone (C) with wild-type human tetherin (WT) and measurement of HIV-1 release in the absence of HIV-1 Vpu (white bar) or presence (black bar). Mutation of positively selected residues I26V, V30G, I36L, T45I (Quad) in the trans-membrane region of human tetherin results in reduced sensitivity to Vpu whilst maintaining similar antiviral activity. The effect of single mutations are also shown. Errors are standard error of the mean of 2 experiments. Equal amounts of tetherin plasmids were used (100 ng) (B) Measurement of HIV-1 p24 in the supernatant of transfected 293T cells by western blot (C) Measurement of HIV-1 Gag levels in extracts from transfected 293T cells. (D) Cell extract blots in C were stripped and re-probed for β actin as a loading control.