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In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation
Published on: March 27, 2016
Proteolytic processing of the astrovirus capsid.
1Department of Pediatrics, Stanford University, Stanford, California 94305, USA. Dorsey.Bass@Forsythe.Stanford.edu
Journal of Virology
|January 22, 2000
Summary
Astrovirus capsid protein undergoes proteolytic processing, converting from an 87-kDa to a 79-kDa form. Trypsin treatment activates minimally infectious astrovirus particles, enhancing their infectivity.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Astrovirus capsid protein undergoes proteolytic processing.
- Understanding astrovirus maturation and infectivity is crucial for controlling viral infections.
Purpose of the Study:
- To characterize the proteolytic processing of the astrovirus capsid protein.
- To investigate the role of trypsin in astrovirus particle maturation and infectivity.
Main Methods:
- Infection of Caco-2 cells with astrovirus.
- Pulse-chase labeling with [35S]Smethionine.
- Electron microscopy, gel electrophoresis, and infectivity assays.
- Monoclonal antibody-based immunoassay for antigenic characterization.
Main Results:
- Astrovirus capsid protein is initially translated as an 87-kDa protein, rapidly converted to a 79-kDa form.
- Trypsin-free astrovirus particles are minimally infectious but become highly infectious after trypsin treatment.
- Trypsin cleavage of the 79-kDa protein yields smaller peptides, correlating with enhanced infectivity.
Conclusions:
- Proteolytic processing is essential for astrovirus infectivity.
- Trypsin plays a critical role in activating astrovirus particles by cleaving the capsid protein.
- The identified cleavage site in a conserved region of ORF2 is key to astrovirus maturation.
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