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Coxsackievirus B3 2A protease promotes encephalomyocarditis virus replication
Qin-Qin Song1, Ming-Zhi Lu1, Juan Song1
1State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China.
Virus Research
|June 9, 2015
Summary
Enterovirus 2A protease (CVB3 2A) enhances Type II internal ribosome entry site (IRES) translation and viral replication. Specific motifs in CVB3 2A are crucial for both IRES activity and eIF4G cleavage.
Area of Science:
- Molecular Virology
- Protein Biochemistry
- RNA Biology
Background:
- Enteroviruses utilize distinct internal ribosome entry site (IRES) elements for cap-independent translation.
- The 2A protease (2Apro) of coxsackievirus B3 (CVB3) is known to cleave eukaryotic initiation factor 4G (eIF4GI), inhibiting cap-dependent translation.
- The interplay between viral proteases and different IRES types in viral replication remains an area of active investigation.
Purpose of the Study:
- To investigate the effect of CVB3 2A protease on Type II IRES-dependent translation and viral replication.
- To determine the role of specific motifs within CVB3 2A protease in mediating IRES activity and eIF4GI cleavage.
Main Methods:
- Transient co-expression of CVB3 2A protease and encephalomyocarditis virus (EMCV) IRES (Type II)-dependent or cap-dependent reporter genes in eukaryotic cells.
- Analysis of reporter gene translation efficiency.
- Site-directed mutagenesis to delete specific motifs within the CVB3 2A protease sequence.
Main Results:
- CVB3 2A protease inhibited cap-dependent translation via eIF4GI cleavage.
- CVB3 2A protease significantly enhanced EMCV Type II IRES-dependent translation and promoted viral replication.
- Deletion of motifs resembling nuclear localization signals (NLS) or a COOH-terminal acidic amino acid motif in CVB3 2A protease reduced both EMCV IRES-dependent translation efficiency and eIF4GI cleavage.
Conclusions:
- CVB3 2A protease possesses a dual function: inhibiting cap-dependent translation and promoting Type II IRES-dependent translation.
- Specific structural motifs within CVB3 2A protease are essential for its activity on both EMCV IRES and eIF4GI.
- These findings offer insights into viral replication mechanisms and potential therapeutic strategies for enterovirus co-infections.
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