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Orthoretroviral-like prototype foamy virus Gag-Pol expression is compatible with viral replication
Anka Swiersy1, Constanze Wiek, Juliane Reh
1Institut für Virologie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Retrovirology
|August 17, 2011
Summary
Foamy viruses (FVs) express Pol separately, unlike orthoretroviruses. Prototype foamy virus (PFV) replication is compatible with orthoretroviral-like Pol expression if processing is possible, and PFV tolerates variations in Gag/Pol levels.
Area of Science:
- Virology
- Molecular Biology
- Retroviral Research
Background:
- Foamy viruses (FVs) differ from orthoretroviruses in expressing Pol as a separate precursor protein, not a Gag-Pol fusion.
- FV packaging involves unique recognition of viral RNA by Pol precursor and Gag, ensuring Pol encapsidation.
Purpose of the Study:
- To investigate if Prototype FV (PFV) replication is compatible with orthoretroviral-like Pol expression.
- To analyze the role of Gag-Pol fusion proteins in PFV particle formation and infectivity.
Main Methods:
- Generation and characterization of various PFV Gag-Pol fusion protein constructs.
- Analysis of extracellular Pol precursor protein in wild-type PFV preparations.
- Assessment of viral replication, particle release, and infectivity under different expression conditions.
Main Results:
- Non-particle-associated, secreted Pol precursor protein was detected in extracellular wild-type PFV.
- PFV replication is compatible with orthoretroviral-like Pol expression, provided proteolytic processing between Gag and Pol occurs.
- PFV Gag-Pol fusion constructs showed varying levels of Pol incorporation and infectivity, with some tolerating significant differences in Gag/Pol ratios.
Conclusions:
- PFV naturally releases non-particle-associated Pol via an unknown mechanism, with rapid processing upon particle incorporation.
- Orthoretroviral-like Pol expression is fundamentally compatible with FV replication if fusion protein processing is maintained.
- PFV exhibits greater tolerance for variations in cellular Gag/Pol levels compared to orthoretroviruses, impacting particle release and infectivity.
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