HIV-1 Vif promotes the formation of high molecular mass APOBEC3G complexes.
HIV-1 Vif inhibits the antiviral activity of APOBEC3G (APO3G) by inducing proteasomal degradation. Here, we studied the effects of Vif on APO3G in vitro. In this system, Vif did not cause APO3G degradation. Instead, Vif induced changes in APO3G that affected immunoprecipitation of the native protein. This effect required wt Vif and was reversed by heat denaturation of APO3G. Sucrose gradient analysis demonstrated that wt Vif induced the gradual transition of APO3G translated in vitro or expressed in HeLa cells from a low molecular mass conformation to puromycin-sensitive high molecular mass (HMM) complexes. In the absence of Vif or the presence of biologically inactive Vif APO3G failed to form HMM complexes. Our results expose a novel function of Vif that promotes the assembly of APO3G into presumably packaging-incompetent HMM complexes and may explain how Vif can overcome the APO3G-imposed block to HIV replication under conditions of no or inefficient APO3G degradation.
Goila-Gaur
Ritu
R
Laboratory of Molecular Microbiology, Viral Biochemistry Section, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892-0460, USA.
Khan
Mohammad A
MA
Miyagi
Eri
E
Kao
Sandra
S
Opi
Sandrine
S
Takeuchi
Hiroaki
H
Strebel
Klaus
K
D000071480:APOBEC-3G Deaminase; D002499:Centrifugation, Density Gradient; D003564:Cytidine Deaminase / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism / Q000472:pathogenicity*; D006367:HeLa Cells; D006358:Hot Temperature; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D009154:Mutation; D014176:Protein Biosynthesis; D011489:Protein Denaturation; D014158:Transcription, Genetic; D054320:vif Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
D054320:vif Gene Products, Human Immunodeficiency Virus; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase