Translocation of the HIV-1 genome into the nucleus of a target cell is a critical step in viral replication in both dividing and non-dividing cells. This process can be attributed to the interaction between the viral preintegration complex and the cellular nuclear import machinery. One of the main regulators of this interaction is viral protein R (Vpr). However, molecular details of Vpr's activity are not understood. In addition, nuclear import of HIV in some cell types appears to be Vpr-independent. Our recent studies have identified heat shock protein 70 (Hsp70) as a substitute for Vpr in such cells, but the molecular reason for this substitution is not known. Our long-range goal is to identify novel targets for anti-HIV intervention. The objective of this application, which is a step in pursuit of that goal, is to define the molecular mechanisms responsible for Vpr's activity in HIV-1 nuclear importation. The central hypothesis of the application is that Vpr (or Hsp70) critically regulates translocation and docking of the HIV-1 preintegration complex to the nuclear envelope, but then dissociates from the preintegration complex to allow its migration through the pore and to the integration site. This hypothesis reconciles findings from our laboratory and reports published by other groups. The rationale for the proposed research is that, once the mechanisms of Vpr/Hsp70 activity are known, agents can be designed to inhibit HIV-1 nuclear import and thus abort infection at a pre-integration step. The central hypothesis will be tested and the objective of the application accomplished by pursuing four specific aims: 1) Characterize HIV-1 preintegration complexes at various stages of maturation; 2) Determine at which step of HIV-1 nuclear import Vpr exerts its activity; 3) Characterize the mechanism(s) of Vpr's nuclear import activity; and 4) Investigate the mechanism of activity of Hsp70 in (HIV-1) nuclear import and its relation to Vpr. The proposed work is innovative, as it capitalizes on recent findings in the field of HIV-1 nuclear import, and will provide important, new information on the previously unknown events and mechanisms governing nuclear translocation of the HIV-1 genome. These results will be significant, because they are expected to facilitate discovery of agents that would inhibit Vpr activity and thus attenuate HIV replication.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI033776-12
Application #
6868862
Study Section
Special Emphasis Panel (ZRG1-AARR-1 (01))
Program Officer
Sharma, Opendra K
Project Start
1993-07-01
Project End
2007-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
12
Fiscal Year
2005
Total Cost
$382,621
Indirect Cost
Name
George Washington University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
043990498
City
Washington
State
DC
Country
United States
Zip Code
20052
Levin, Aviad; Loyter, Abraham; Bukrinsky, Michael (2011) Strategies to inhibit viral protein nuclear import: HIV-1 as a target. Biochim Biophys Acta 1813:1646-53
Li, Ge; Elder, Robert T; Dubrovsky, Larisa et al. (2010) HIV-1 replication through hHR23A-mediated interaction of Vpr with 26S proteasome. PLoS One 5:e11371
Li, Ge; Bukrinsky, Michael; Zhao, Richard Y (2009) HIV-1 viral protein R (Vpr) and its interactions with host cell. Curr HIV Res 7:178-83
Iordanskiy, Sergey N; Bukrinsky, Michael I (2009) Analysis of viral and cellular proteins in HIV-1 reverse transcription complexes by co-immunoprecipitation. Methods Mol Biol 485:121-34
Iordanskiy, Sergey; Berro, Reem; Altieri, Maria et al. (2006) Intracytoplasmic maturation of the human immunodeficiency virus type 1 reverse transcription complexes determines their capacity to integrate into chromatin. Retrovirology 3:4
Haffar, Omar; Dubrovsky, Larisa; Lowe, Richard et al. (2005) Oxadiazols: a new class of rationally designed anti-human immunodeficiency virus compounds targeting the nuclear localization signal of the viral matrix protein. J Virol 79:13028-36
Iordanskiy, Sergey; Zhao, Yuqi; Dubrovsky, Larisa et al. (2004) Heat shock protein 70 protects cells from cell cycle arrest and apoptosis induced by human immunodeficiency virus type 1 viral protein R. J Virol 78:9697-704
Agostini, I; Popov, S; Li, J et al. (2000) Heat-shock protein 70 can replace viral protein R of HIV-1 during nuclear import of the viral preintegration complex. Exp Cell Res 259:398-403
Bukrinsky, M I; Haffar, O K (1999) HIV-1 nuclear import: in search of a leader. Front Biosci 4:D772-81
Haffar, O K; Smithgall, M D; Popov, S et al. (1998) CNI-H0294, a nuclear importation inhibitor of the human immunodeficiency virus type 1 genome, abrogates virus replication in infected activated peripheral blood mononuclear cells. Antimicrob Agents Chemother 42:1133-8

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