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Molecular studies on bromovirus capsid protein.
Y G Choi1, G L Grantham, A L Rao
1Department of Plant Pathology, University of California, Riverside, California 92521-0122, USA.
Virology
|May 4, 2000
Summary
The Brome mosaic virus coat protein's arginine-rich motif is crucial for packaging specific viral RNAs. Deleting parts of this motif disrupts virion assembly and RNA stability, impacting viral replication.
Area of Science:
- Virology
- Molecular Biology
- Plant Pathology
Background:
- Brome mosaic virus (BMV) encapsidation involves interactions between its coat protein (CP) and viral RNAs.
- The N-proximal arginine-rich motif (ARM) of BMV CP is highly conserved and implicated in RNA binding.
Purpose of the Study:
- To investigate the specific roles of the BMV CP's N-terminal ARM in viral RNA packaging and virion assembly.
- To characterize the impact of ARM deletions on the stability of BMV genomic and subgenomic RNAs within virions.
Main Methods:
- Engineered deletions in BMV RNA3 to create CP variants lacking the ARM or specific arginine residues.
- Analyzed virion RNA from infected plants using Northern blot hybridization.
- Performed in vitro reassembly assays to assess RNA packaging.
Main Results:
- Deletions in the ARM region differentially affected the packaging and stability of BMV genomic RNAs.
- A specific deletion (B3/Delta919) led to instability of virions containing RNA1 and the accumulation of a truncated RNA1 species.
- The N-terminal ARM contains essential amino acids for packaging RNA4, independent of genomic RNA3.
Conclusions:
- The BMV CP's N-terminal ARM plays distinct roles in interacting with different viral RNAs during encapsidation.
- Specific arginine residues within the ARM are critical for RNA packaging and virion stability.
- These findings provide insights into the molecular mechanisms of Bromovirus CP-RNA interactions during virion assembly.