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HIV genetic variation is directed and restricted by DNA precursor availability
J P Vartanian1, U Plikat, M Henry
1Unité de Rétrovirologie Moléculaire, Institut Pasteur, Paris, France.
Journal of Molecular Biology
|July 11, 1997
Summary
Deoxynucleoside triphosphate (dNTP) imbalances can cause human immunodeficiency virus type 1 (HIV-1) to produce hypermutants. Host cell restrictions and specific dNTP distortions influence viral mutation patterns.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Deoxynucleoside triphosphate (dNTP) pools are crucial for DNA replication fidelity.
- Imbalances in dNTP concentrations are known to introduce errors during DNA synthesis.
- The fidelity of human immunodeficiency virus type 1 (HIV-1) replication is essential for its lifecycle and evolution.
Purpose of the Study:
- To investigate the impact of dNTP imbalances on HIV-1 replication fidelity.
- To characterize the types of mutations (hypermutants) produced under dNTP biased conditions.
- To compare the in vitro generated mutant spectrum with naturally occurring HIV-1 hypermutants.
Main Methods:
- Using detergent-permeabilized HIV-1 virions with controlled, biased dNTP concentrations.
- Employing a genetic screen utilizing the blue/white beta-galactosidase complementation assay.
- Analyzing mutations in HIV-1 recovered from infected U937 cells and primary peripheral blood mononuclear cells (PBMCs).
Main Results:
- Biased dNTP concentrations readily produced various hypermutants in vitro.
- The spectrum of induced hypermutants differed from naturally occurring ones, suggesting host cell influence.
- G --> A hypermutants were specifically recovered from thymidine-treated HIV-infected U937 cells.
- A small percentage (1-2%) of primary cells (resting or activated PBMCs) yielded hypermutants, indicating endogenous dNTP distortions.
Conclusions:
- dNTP imbalances can significantly affect HIV-1 replication fidelity, leading to hypermutation.
- Host cellular mechanisms may modulate or restrict the spectrum of viral mutations.
- Endogenous dNTP pool distortions in a fraction of primary cells could contribute to somatic and germline mutations, influencing mammalian and viral genome evolution.