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Exogenous Rubella Virus Capsid Proteins Enhance Virus Genome Replication
Min-Hsin Chen1, Cara C Burns1, Emily Abernathy1
1Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Pathogens (Basel, Switzerland)
|June 24, 2022
Summary
Exogenous rubella virus (RuV) capsid proteins (CP) enhance viral genome replication by aiding early stages, potentially by protecting viral RNA. This finding suggests a new role for CP in RuV replication dynamics.
Area of Science:
- Virology
- Molecular Biology
- RNA Replication
Background:
- Rubella virus (RuV) replication and its enhancement by de novo synthesized viral structural proteins, including capsid proteins (CP), are known.
- The specific role of exogenous CP (CP present in virus particles) in modulating viral genome replication remained unclear.
Purpose of the Study:
- To investigate whether exogenous rubella virus capsid proteins (CP) influence viral genome replication.
- To elucidate the mechanism by which exogenous CP might enhance RuV replication.
Main Methods:
- Transfection of RuV replicons with and without recombinant CP (rCP).
- Analysis of viral RNA synthesis, translation efficiency, non-structural protein (NSP) distribution, and RNA stability.
- Assessment of rCP's effect on replication-deficient RuV mutants.
Main Results:
- Exogenous RuV CP significantly enhanced viral genome replication, evidenced by increased negative-strand RNA synthesis.
- CP did not affect translation efficiency, NSP localization, or subgenomic RNA synthesis.
- rCP partially restored replication of some NSP mutants but not those with defects in positive-strand RNA synthesis.
- rCP stabilized RuV replicon RNAs post-transfection.
Conclusions:
- Exogenous rubella virus CP enhance viral genome replication by modulating early replication stages, likely before or at the initiation of negative-strand RNA synthesis.
- CP may exert this effect through a general mechanism, such as protecting viral RNA from degradation.
- This study reveals a novel function for exogenous CP in Rubella virus replication.
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