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3CD, but not 3C, cleaves the VP1/2A site efficiently during Aichi virus polyprotein processing through interaction
Jun Sasaki1, Kumiko Ishikawa, Koki Taniguchi
1Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan. jsasaki@fujita-hu.ac.jp
Virus Research
|January 10, 2012
Summary
Aichi virus (AiV) polyprotein processing relies on the 3CD protease, not 3C alone. Efficient cleavage at the VP1/2A site requires 3CD to interact with the 2A region.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Picornavirus genomes encode a polyprotein processed by viral proteases.
- Aichi virus (AiV), a human gastroenteritis pathogen, belongs to the Kobuvirus genus.
- AiV leader (L) and 2A proteins lack protease activity.
Purpose of the Study:
- To investigate the roles of AiV 3C and 3CD proteases in polyprotein processing.
- To elucidate the mechanism of VP1/2A site cleavage by AiV proteases.
Main Methods:
- Cell-free translation system for polyprotein processing assays.
- Mammalian two-hybrid and coimmunoprecipitation assays for protein interactions.
- Site-directed mutagenesis of 3CD and 2A proteins.
Main Results:
- Both 3C and 3CD proteases processed the AiV polyprotein.
- 3CD was significantly more efficient than 3C at cleaving the VP1/2A site.
- An interaction between 2A and 3CD was identified and correlated with efficient VP1/2A cleavage.
Conclusions:
- AiV polyprotein processing is primarily mediated by the 3CD protease.
- Efficient cleavage at the VP1/2A site necessitates the interaction between 3CD and the 2A region of the polyprotein.
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