Figure 1. Enhancement of viral particle release in absence of Vpu-dependent reduction of Tetherin steady-state levels.

HEK 293T cells were co-transfected with a fixed amount of the HA-Tetherin-expressing plasmid (235 ng) and the indicated amounts of HxBH10 proviral constructs. Forty-eight hours post-transfection, cells and virus-containing supernatants were harvested and processed for western blot analysis. (A) Proteins in the viral and cell lysates were detected using specific Abs. (B) Quantification of HIV-1 release efficiency. Bands corresponding to Gag products in cells and viral particles in panel (A), as detected using anti-p24 Abs, were scanned by laser densitometry. The virus particle release efficiency was determined as described in the Materials and Methods and calculated as a percentage of the release of HxBH10-vpu+ (100%) in absence of HA-Tetherin. The values within the graph represent the fold increase of virus particle release upon Vpu expression.