Currently, the HIV pandemic remains a major global health challenge. In order to effectively control and cure HIV-1 infection, it is necessary to perform greater research on host-HIV interactions and develop novel preventive and therapeutic approaches. The human cytidine deaminase APOBEC3G (A3G) is the first identified host restriction factor, which can serve as an initial line of defense against HIV-1 by inducing lethal mutations on proviral DNA and disrupting viral reverse transcription and integration.
In order to better understand the action of A3G on HIV-1 replication, my study was focused on characterizing the interplay between A3G and HIV-1 reverse transcriptase (RT). The results indicated that A3G directly bound to RT, which contributed to A3G-mediated inhibition of viral reverse transcription. Overexpression of the RT-binding polypeptide A3G65-132 was able to disrupt wild-type A3G and RT interaction, consequently attenuating the anti-HIV effect of A3G on HIV replication.
While the potent antiviral activities of A3G make it an attractive candidate for gene therapy, the actions of A3G can be counteracted by HIV-1 Vif during wild-type HIV infection. In order to overcome Vif-mediated blockage and maximize the antiviral activity of A3G, this protein was fused with a virus-targeting polypeptide (R88) derived from HIV-1 Vpr, and various mutations were then introduced into R88-A3G fusion protein. Results showed that Vif binding mutants R88-A3GD128K and R88-A3GP129A exhibited very potent antiviral activity, and blocked HIV-1 replication in a CD4+ T lymphocyte cell line as well as human primary cells. In an attempt to further determine their potential against drug resistant viruses and viruses produced from latently infected cells, R88-A3GD128K was chosen and delivered by an inducible lentiviral vector system. Expression of R88-A3GD128K in actively and latently HIV-1 infected cells was shown to be able to inhibit the replication of both drug sensitive and resistant strains of HIV-1.
In conclusion, this thesis has demonstrated one of the mechanisms that how A3G can disrupt HIV-1 reverse transcription. Meanwhile, an A3G-based anti-HIV-1 strategy has been developed, which provides a proof-of-principle for a new gene therapy approach against this deadly virus.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:MWU.1993/23226 |
| Date | 10 1900 |
| Creators | Wang, Xiaoxia |
| Contributors | Yao, Xiao-Jian (Medical Microbiology), Ball, Blake T (Medical Microbiology) Li, Yan (Medical Microbiology) Kung, Sam (Immunology) Liang, Chen (McGill University) |
| Publisher | American Society for Microbiology, Mary Ann Liebert, Inc. |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Detected Language | English |
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