Advertisement

 

 

Vpu-Mediated Counteraction of Tetherin Is a Major Determinant of HIV-1 Interferon Resistance.

Vpu-Mediated Counteraction of Tetherin Is a Major Determinant of HIV-1 Interferon Resistance.
Author Information (click to view)

Kmiec D, Iyer SS, Stürzel CM, Sauter D, Hahn BH, Kirchhoff F,


Kmiec D, Iyer SS, Stürzel CM, Sauter D, Hahn BH, Kirchhoff F, (click to view)

Kmiec D, Iyer SS, Stürzel CM, Sauter D, Hahn BH, Kirchhoff F,

Advertisement
Share on FacebookTweet about this on TwitterShare on LinkedIn

mBio 2016 08 167(4) doi 10.1128/mBio.00934-16

Abstract
UNLABELLED
Human immunodeficiency virus type 1 (HIV-1) groups M, N, O, and P are the result of independent zoonotic transmissions of simian immunodeficiency viruses (SIVs) infecting great apes in Africa. Among these, only Vpu proteins of pandemic HIV-1 group M strains evolved potent activity against the restriction factor tetherin, which inhibits virus release from infected cells. Thus, effective Vpu-mediated tetherin antagonism may have been a prerequisite for the global spread of HIV-1. To determine whether this particular function enhances primary HIV-1 replication and interferon resistance, we introduced mutations into the vpu genes of HIV-1 group M and N strains to specifically disrupt their ability to antagonize tetherin, but not other Vpu functions, such as degradation of CD4, down-modulation of CD1d and NTB-A, and suppression of NF-κB activity. Lack of particular human-specific adaptations reduced the ability of HIV-1 group M Vpu proteins to enhance virus production and release from primary CD4(+) T cells at high levels of type I interferon (IFN) from about 5-fold to 2-fold. Interestingly, transmitted founder HIV-1 strains exhibited higher virion release capacity than chronic control HIV-1 strains irrespective of Vpu function, and group M viruses produced higher levels of cell-free virions than an N group HIV-1 strain. Thus, efficient virus release from infected cells seems to play an important role in the spread of HIV-1 in the human population and requires a fully functional Vpu protein that counteracts human tetherin.

IMPORTANCE
Understanding which human-specific adaptations allowed HIV-1 to cause the AIDS pandemic is of great importance. One feature that distinguishes pandemic HIV-1 group M strains from nonpandemic or rare group O, N, and P viruses is the acquisition of mutations in the accessory Vpu protein that confer potent activity against human tetherin. Adaptation was required because human tetherin has a deletion that renders it resistant to the Nef protein used by the SIV precursor of HIV-1 to antagonize this antiviral factor. It has been suggested that these adaptations in Vpu were critical for the effective spread of HIV-1 M strains, but direct evidence has been lacking. Here, we show that these changes in Vpu significantly enhance virus replication and release in human CD4(+) T cells, particularly in the presence of IFN, thus supporting an important role in the spread of pandemic HIV-1.

Submit a Comment

Your email address will not be published. Required fields are marked *

11 + 9 =

[ HIDE/SHOW ]