HIV-1 accessory proteins VPR and Vif modulate antiviral response by targeting IRF-3 for degradation

Virology. 2008 Mar 30;373(1):85-97. doi: 10.1016/j.virol.2007.10.042. Epub 2007 Dec 20.

Abstract

The activation of IRF-3 during the early stages of viral infection is critical for the initiation of the antiviral response; however the activation of IRF-3 in HIV-1 infected cells has not yet been characterized. We demonstrate that the early steps of HIV-1 infection do not lead to the activation and nuclear translocation of IRF-3; instead, the relative levels of IRF-3 protein are decreased due to the ubiquitin-associated proteosome degradation. Addressing the molecular mechanism of this effect we show that the degradation is independent of HIV-1 replication and that virion-associated accessory proteins Vif and Vpr can independently degrade IRF-3. The null mutation of these two genes reduced the capacity of the HIV-1 virus to down modulate IRF-3 levels. The degradation was associated with Vif- and Vpr-mediated ubiquitination of IRF-3 and was independent of the activation of IRF-3. N-terminal lysine residues were shown to play a critical role in the Vif- and Vpr-mediated degradation of IRF-3. These data implicate Vif and Vpr in the disruption of the initial antiviral response and point to the need of HIV-1 to circumvent the antiviral response during the very early phase of replication.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Line
  • Down-Regulation*
  • HIV-1 / metabolism
  • HIV-1 / pathogenicity*
  • Humans
  • Interferon Regulatory Factor-3 / metabolism*
  • Mutation
  • Ubiquitin / metabolism*
  • vif Gene Products, Human Immunodeficiency Virus / genetics
  • vif Gene Products, Human Immunodeficiency Virus / metabolism*
  • vpr Gene Products, Human Immunodeficiency Virus / genetics
  • vpr Gene Products, Human Immunodeficiency Virus / metabolism*

Substances

  • Interferon Regulatory Factor-3
  • Ubiquitin
  • vif Gene Products, Human Immunodeficiency Virus
  • vpr Gene Products, Human Immunodeficiency Virus