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Updated: May 18, 2026
09:08
Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
Evidence that viral RNAs have evolved for efficient, two-stage packaging.
Alexander Borodavka1, Roman Tuma, Peter G Stockley
1Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
Summary
Viral RNA genome packaging is a two-stage process. Genomic RNA rapidly collapses upon coat protein addition, facilitating efficient and accurate capsid assembly, a mechanism distinct from nonviral RNA.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Genome packaging is crucial for virus replication and a target for antiviral drugs.
- Previously, viral RNA genome packaging was thought to occur via gradual co-assembly with capsid subunits.
Purpose of the Study:
- To investigate the real-time mechanism of viral RNA genome packaging.
- To determine if RNA conformation changes influence capsid assembly efficiency and specificity.
Main Methods:
- Utilized a single-molecule fluorescence assay to monitor RNA conformation and virus assembly in real time.
- Studied two viruses from different structural families.
- Examined interactions between viral RNA and cognate coat proteins.
Main Results:
- Discovered a two-stage genome packaging process, initiated by rapid RNA conformational collapse (20-30%) upon coat protein addition.
- This collapse, occurring at substoichiometric protein ratios, precedes gradual particle growth.
- Nonviral RNAs of similar size did not collapse and formed aberrant structures, unlike viral RNAs which formed correct-sized capsids.
Conclusions:
- Conformational collapse is a specific feature of viral RNA, evolved to facilitate efficient and accurate genome packaging.
- The process involves specific RNA-protein and protein-protein interactions, ensuring correct capsid formation.
- This mechanism shares similarities with ribosome assembly processes.
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