Vpr14-88-Apobec3G fusion protein is efficiently incorporated into Vif-positive HIV-1 particles and inhibits viral infection

• Published in: PloS one Vol. 3; no. 4; p. e1995
• Main Authors: Ao, Zhujun, Yu, Zhe, Wang, Lina, Zheng, Yingfeng, Yao, Xiaojian
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16.04.2008; Public Library of Science (PLoS)
• Subjects: Analysis; Antiviral activity; Antiviral agents; APOBEC-3G Deaminase; Biotechnology; Cassettes; CCR5 protein; CD4 antigen; CD4-Positive T-Lymphocytes - virology; Cell Line; Cell lines; Complementary DNA; Cytidine Deaminase - chemistry; Cytidine Deaminase - genetics; Deoxycytidine deaminase; Deoxyribonucleic acid; DNA; DNA repair; Fusion protein; Gene Products, vif - chemistry; Gene Products, vif - genetics; Health aspects; HeLa Cells; HIV; HIV Infections - metabolism; HIV-1 - metabolism; Human immunodeficiency virus; Humans; Infection; Infections; Infectious Diseases/HIV Infection and AIDS; Infectious Diseases/Viral Infections; Infectivity; Laboratories; Leukocytes, Mononuclear - virology; Lymphocytes; Lymphocytes T; Medicine; Molecular weight; Mutation; Optimization; Plasmids - metabolism; Proteins; Recombinant Fusion Proteins - chemistry; Reverse transcription; T cells; Transcription (Genetics); Transcription, Genetic; Viral infections; Virions; Virology/Antivirals, including Modes of Action and Resistance; Virology/Immunodeficiency Viruses; Virology/New Therapies, including Antivirals and Immunotherapy; Virology/Viral and Gene Regulation; Virus replication; Viruses; vpr Gene Products, Human Immunodeficiency Virus - chemistry; vpr Gene Products, Human Immunodeficiency Virus - metabolism; Vpr protein
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0001995

APOBEC3G (A3G), a deoxycytidine deaminase, is a potent host antiviral factor that can restrict HIV-1 infection. During Vif-negative HIV-1 replication, A3G is incorporated into HIV-1 particles, induces mutations in reverse transcribed viral DNA and inhibits reverse transcription. However, HIV-1 Vif counteracts A3G's activities by inducing its degradation and by blocking its incorporation into HIV-1 particles. Thus, it is interesting to elucidate a mechanism that would allow A3G to escape the effects of Vif in order to rescue its potent antiviral activity and to provide a possible novel therapeutic strategy for treating HIV-1 infection. In this study, we generated an R88-A3G fusion protein by fusing A3G to a virion-targeting polypeptide (R14-88) derived from HIV-1 Vpr protein and compared its antiviral effects relative to those of HA-tagged native A3G (HA-A3G). Our study showed that transient expression of the R88-A3G fusion protein in both Vif(-) and Vif(+) HIV-1 producing cells drastically inhibited viral infection in HeLa-CD4-CCR5-cells, CD4(+) C8166 T cells and human primary PBMCs. Moreover, we established CD4(+) C8166 T cell lines that stably express either R88-A3G or HA-A3G by transduction with VSV-G-pseudotyped lentiviral vector that harbor expression cassettes for R88-A3G or HA-A3G, respectively, and tested their susceptibility to Vif(+) HIV-1 infection. Our results clearly reveal that expression of R88-A3G in transduced CD4(+) C8166 cells significantly blocked Vif(+) HIV-1 infection. In an attempt to understand the mechanism underlying the antiviral activity of R88-A3G, we demonstrated that R88-A3G was efficiently incorporated into viral particles in the presence of Vif. Moreover, PCR analysis revealed that R88-A3G significantly inhibited viral cDNA synthesis during the early stage of Vif(+) virus infection. Our results clearly indicate that R88 delivers A3G into Vif(+) HIV-1 particles and inhibits infectivity and spread of the virions among CD4(+) T cells. This study provides evidence for an effective strategy to modify a host protein with innate anti-HIV-1 activity and rescue its potent anti-HIV potential in the presence of Vif. Further characterization and optimization of this system may lead to the development of an effective therapeutic approach against HIV-1 infection.