The virus infectivity factor (Vif) is a protein encoded by most primate lentiviruses. Recent evidence suggests that HIV-1 Vif reduces the intracellular levels of the host cytidine deaminase APOBEC3G (Apo3G) and inhibits its packaging into virions. These functions of Vif are thought to be species-specific. Accordingly, HIV-1 Vif can target only human Apo3G (hApo3G), whereas, African green monkey simian immunodeficiency virus (SIVagm) Vif can inhibit African green monkey but not human Apo3G. Consistent with this, we found that SIVagm Vif does not affect the stability of exogenously and endogenously expressed hApo3G and does not prevent packaging of exogenous and endogenous hApo3G into SIVagm virions. Nevertheless, SIVagm Vif supported spreading infection of SIVagm virus in the hApo3G-positive human A3.01 T cell line and rescued infectivity of viruses produced from Apo3G-expressing HeLa cells. Sequence analysis verified that SIVagm Vif inhibited the accumulation of hApo3G-induced mutations, suggesting that SIVagm Vif is indeed active in human cells. Our data suggest that SIVagm Vif can inhibit hApo3G activity without inducing its intracellular degradation or preventing its packaging into virions.
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http://dx.doi.org/10.1074/jbc.M408987200 | DOI Listing |
J Virol
November 2016
Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
Unlabelled: Lentiviruses have evolved the Vif protein to counteract APOBEC3 (A3) restriction factors by targeting them for proteasomal degradation. Previous studies have identified important residues in the interface of human immunodeficiency virus type 1 (HIV-1) Vif and human APOBEC3C (hA3C) or human APOBEC3F (hA3F). However, the interaction between primate A3C proteins and HIV-1 Vif or natural HIV-1 Vif variants is still poorly understood.
View Article and Find Full Text PDFInorg Chem
May 2014
Department of Biochemistry and Molecular Biology Uniformed Services University of the Health Sciences 4301 Jones Bridge Road, Bethesda, Maryland 20814-4799 United States.
HIV-1 virion infectivity factor (Vif) is an accessory protein that induces the proteasomal degradation of the host restriction factor, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G). Degradation of APOBEC3G requires the interaction of Vif with Cul5, the scaffold for an E3 ubiquitin ligase. A highly conserved region in HIV-1 Vif termed the HCCH motif binds zinc and is critical for recruitment of Cul5 and degradation of APOBEC3G.
View Article and Find Full Text PDFJ Virol
November 2013
The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
APOBEC3G (A3G) is a cytidine deaminase that restricts human immunodeficiency virus type 1 (HIV-1) and other lentiviruses. Most of these viruses encode a Vif protein that directly binds A3G and leads to its proteasomal degradation. Both Vif proteins of HIV-1 and African green monkey simian immunodeficiency virus (SIVagm) bind residue 128 of A3G.
View Article and Find Full Text PDFPLoS One
May 2013
Faculty of Life Sciences and Biotechnology, South Asian University, Akbar Bhawan, Chanakyapuri, New Delhi, India.
Human immunodeficiency virus type 1 (HIV-1) Vif is essential for viral evasion of the host antiviral protein APOBEC3G (APO3G). The Vif protein from a distantly related African green monkey (Agm) simian immunodeficiency virus (SIVagm) is unable to suppress the antiviral activity of human APO3G but is active against Agm APO3G. SIVmac Vif on the other hand, possesses antiviral activity against both human and Agm APO3G.
View Article and Find Full Text PDFJ Virol
September 2010
Departments of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824-4320, USA.
Primate lentiviruses are unique in that they produce several accessory proteins to help in the establishment of productive viral infection. The major function of these proteins is to clear host resistance factors that inhibit viral replication. Vif is one of these proteins.
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