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Functional analyses reveal extensive RRE plasticity in primary HIV-1 sequences selected under selective pressure
Francesc Cunyat1, Nancy Beerens2, Elisabet García1
1IrsiCaixa-HIVACAT, Institut de Recerca en Ciències de la Salut Germans Trias i Pujol (IGTP), Hospital Germans Trias, Universitat Autònoma de Barcelona, Badalona, Barcelona, Catalonia, Spain.
Plos One
|August 30, 2014
Summary
HIV-1 Rev response element (RRE) variants selected during Enfuvirtide treatment show structural changes but maintain Rev binding and RNA export function. This suggests RRE malleability in vivo, challenging current models for antiviral development.
Area of Science:
- Virology
- Molecular Biology
- Structural Biology
Background:
- The HIV-1 Rev response element (RRE) is crucial for viral replication, mediating mRNA export via Rev protein binding.
- Structural changes in RRE sequences may affect its function, but this has not been functionally validated.
- Enfuvirtide pressure in vivo may select for RRE variants with altered genetic and structural properties.
Purpose of the Study:
- To investigate genetic, structural, and functional variations in HIV-1 RRE sequences selected under Enfuvirtide pressure.
- To assess the impact of these variations on Rev binding and viral mRNA export.
- To evaluate the functional consequences of RRE variants during HIV replication.
Main Methods:
- Isolation of RRE variants from HIV-1 strains of patients failing Enfuvirtide therapy.
- Prediction of secondary structures for obtained RRE variants.
- Assessment of Rev binding using gel-shift assays.
- Functional evaluation of RNA export efficiency using cell-based reporter assays.
- Analysis of virus replication in lymphoid cells.
Main Results:
- Multiple RRE variants with altered predicted secondary structures were identified.
- One variant showed abrogation of the primary Rev binding site.
- Most variants maintained Rev binding and mRNA export efficiency.
- Specific variants (RRE45, RRE40-45) exhibited reduced Rev binding in vitro.
- In vitro binding defects did not translate to impaired RNA export or replication in vivo, indicating RRE plasticity.
Conclusions:
- HIV-1 RRE function remains largely unaffected in variants selected during Enfuvirtide treatment.
- Current models of the Rev-RRE complex structure are insufficient to predict the function of naturally occurring mutants.
- These findings necessitate a re-evaluation for developing antiviral agents targeting the Rev-RRE interaction.
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