Human-Specific Adaptations in Vpu Conferring Anti-tetherin Activity Are Critical for Efficient Early HIV-1 Replication In Vivo

Publication date: 10 January 2018
Source:Cell Host & Microbe, Volume 23, Issue 1
Author(s): Eri Yamada, Shinji Nakaoka, Lukas Klein, Elisabeth Reith, Simon Langer, Kristina Hopfensperger, Shingo Iwami, Gideon Schreiber, Frank Kirchhoff, Yoshio Koyanagi, Daniel Sauter, Kei Sato
The HIV-1-encoded accessory protein Vpu exerts several immunomodulatory functions, including counteraction of the host restriction factor tetherin, downmodulation of CD4, and inhibition of NF-κB activity to facilitate HIV-1 infection. However, the relative contribution of individual Vpu functions to HIV-1 infection in vivo remained unclear. Here, we used a humanized mouse model and HIV-1 strains with selective mutations in vpu to demonstrate that the anti-tetherin activity of Vpu is a prerequisite for efficient viral spread during the early phase of infection. Mathematical modeling and gain-of-function mutations in SIVcpz, the simian precursor of pandemic HIV-1, corroborate this finding. Blockage of interferon signaling combined with transcriptome analyses revealed that basal tetherin levels are sufficient to control viral replication. These results establish tetherin as a key effector of the intrinsic immune defense against HIV-1, and they demonstrate that Vpu-mediated tetherin antagonism is critical for efficient viral spread during the initial phase of HIV-1 replication.

Graphical abstract

Teaser

The HIV-1-encoded accessory protein Vpu exerts several functions. Using a humanized mouse model and HIV-1 Vpu mutant viruses, Yamada et al. demonstrate that Vpu-mediated antagonism of the interferon-induced antiviral protein tetherin is critical for efficient viral spread during the initial phase of HIV-1 replication in vivo.


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