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10:49
In vitro Uncoating of HIV-1 Cores
Published on: November 8, 2011
Human immunodeficiency virus type 1 preintegration complexes: studies of organization and composition
M D Miller1, C M Farnet, F D Bushman
1Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Journal of Virology
|July 1, 1997
Summary
Human immunodeficiency virus type 1 (HIV-1) preintegration complexes (PICs) condense viral DNA for integration. Proteins associate with DNA ends, facilitating efficient viral cDNA integration.
Area of Science:
- Virology
- Molecular Biology
- Structural Biology
Background:
- Human immunodeficiency virus type 1 (HIV-1) utilizes preintegration complexes (PICs) for cDNA integration into host genomes.
- Understanding PIC organization is crucial for developing antiviral strategies.
Purpose of the Study:
- To investigate the structural organization and protein composition of HIV-1 PICs.
- To elucidate the role of specific viral and host proteins in PIC function and cDNA integration.
Main Methods:
- Isolation and biochemical analysis of PICs from infected cells.
- In vitro integration assays.
- Protease protection assays using endo- and exonucleases.
- Cofractionation studies to identify associated proteins.
Main Results:
- HIV-1 PICs contain condensed cDNA, with ends likely linked by proteins.
- Viral matrix and reverse transcriptase (RT) proteins cofractionate with PICs, while capsid and nucleocapsid proteins dissociate.
- cDNA ends are protected from exonucleases but susceptible to endonucleases.
- Integrase cleavage at 3' ends is essential for integration competency, suggesting a role in defining heterogeneous cDNA termini.
Conclusions:
- PICs are organized with proteins tightly associated at cDNA ends and loosely with intervening cDNA, within a remnant of the viral core.
- Integrase-mediated cleavage refines the heterogeneous cDNA ends generated by RT, ensuring integration competence.
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