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High Throughput In Vitro Assessment of Latency Reversing Agents on HIV Transcription and Splicing
Published on: January 22, 2019
Vpr is required for efficient Nef expression from unintegrated human immunodeficiency virus type 1 DNA.
Betty Poon1, Michael A Chang, Irvin S Y Chen
1Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine at UCLA, UCLA AIDS Institute and Jonsson Comprehensive CAncer Center, 11-934 Factor Building, 10833 Le Conte Avenue, Los Angeles, CA 90095-1678, USA.
Journal of Virology
|July 27, 2007
Summary
Human immunodeficiency virus (HIV) Vpr protein enhances expression from unintegrated viral DNA. This process, independent of Tat, leads to Nef expression and CD4 receptor downregulation on infected cells.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Unintegrated human immunodeficiency virus (HIV) DNA can express viral RNA and proteins, unlike integrated proviral DNA.
- Previous research indicated HIV Vpr enhances expression from integrase-defective HIV.
Purpose of the Study:
- To investigate the mechanism by which HIV Vpr enhances expression from unintegrated viral DNA.
- To determine the role of Vpr and Tat in the expression of viral RNA and proteins from unintegrated HIV DNA.
Main Methods:
- Utilized integrase-defective HIV constructs.
- Performed mutation studies on Vpr and Tat proteins.
- Analyzed viral RNA transcription (gag and nef).
- Assessed CD4 receptor expression on infected cells.
Main Results:
- Vpr activation of expression from unintegrated DNA is partially dependent on an active HIV promoter.
- Vpr increases transcription of unspliced gag and spliced nef viral RNA.
- Tat is not affected by Vpr and is dispensable for Vpr-mediated enhancement.
- Virion-associated Vpr alone is sufficient for Nef expression and CD4 downregulation.
Conclusions:
- HIV Vpr plays a crucial role in enhancing the expression of viral products from unintegrated HIV DNA.
- Vpr-mediated Nef expression from unintegrated DNA leads to CD4 downregulation, a key step in viral pathogenesis.
