The Role of Vpr in the Regulation of HIV-1 Gene Expression

Expression of the viral protein R, Vpr, of HIV-1 affects many biological events in host cells including cell cycle progression, and modulates HIV-1 gene transcription. Earlier studies implicated the cellular protein p21WAF1 (p21) in regulating HIV-1 transcription, which led us to investigate the fun...

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Bibliographic Details
Published in:Cell cycle (Georgetown, Tex.) Tex.), 2006-11, Vol.5 (22), p.2626-2638
Main Authors: Cui, Jianqi, Tungaturthi, Parithosh K, Ayyavoo, Velpandi, Ghafouri, Mohammad, Ariga, Hiroyoshi, Khalili, Kamel, Srinivasan, Alagarsamy, Amini, Shohreh, Sawaya, Bassel E
Format: Article
Language:English
Subjects:
Binding
Binding Sites
Biology
Bioscience
Calcium
Cancer
Cell
Cell Cycle
Cell Line, Tumor
Cell Nucleus - metabolism
Cycle
Cyclin-Dependent Kinase Inhibitor p21 - metabolism
Cytoplasm - metabolism
E1A-Associated p300 Protein - metabolism
Gene Expression Regulation, Viral
Gene Products, vpr - genetics
Gene Products, vpr - metabolism
HCT116 Cells
HIV Long Terminal Repeat
HIV-1 - genetics
HIV-1 - metabolism
Humans
Landes
Microscopy, Fluorescence
Models, Biological
Organogenesis
Proteins
Transfection
vpr Gene Products, Human Immunodeficiency Virus
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Summary:Expression of the viral protein R, Vpr, of HIV-1 affects many biological events in host cells including cell cycle progression, and modulates HIV-1 gene transcription. Earlier studies implicated the cellular protein p21WAF1 (p21) in regulating HIV-1 transcription, which led us to investigate the functional and physical interaction of Vpr and p21. Our results show that Vpr modestly activated HIV-LTR in cells lacking p21 gene. We described the mechanisms of p21 and Vpr interaction for stimulating transcription of HIV-1. Data from the protein-protein interaction experiments revealed the ability of Vpr, p21 and p300 to form a complex. Further, we showed that, Vpr interacted with the N- and the C-terminal domains of p21. Furthermore, in cells expressing Vpr, p21 localizes to both the cytoplasm and the nucleus. Additionally, expression of Vpr alleviates p21-mediated inhibition of cell departure from G1 phase. Expression of a mutant Vpr, with arginine 73 altered to serine, did not affect p21 ability to cause cell arrest or its sub- cellular localization. These observations revealed a new cellular partner for Vpr, and provided a new therapeutic avenue for controlling HIV-1 expression.
ISSN:1538-4101
1551-4005
DOI:10.4161/cc.5.22.3442