Related Experiment Videos
Mengovirus leader is involved in the inhibition of host cell protein synthesis
J Zoll1, J M Galama, F J van Kuppeveld
1Department of Medical Microbiology, University of Nijmegen, The Netherlands.
Abstract:
The presence of a leader peptide in picornaviruses is restricted to the Cardiovirus and Aphthovirus genera. However, the leader peptides of these two genera are structurally and functionally unrelated. The aphthovirus leader is a protease involved in viral polyprotein processing and host cell translation shutoff. The function of the cardiovirus leader peptide is still unknown. To gain an insight into the function of the cardiovirus leader peptide, a mengovirus leader peptide deletion mutant was constructed. The deletion mutant was able to grow at a reduced rate in baby hamster kidney cells (BHK-21). Mutant virus production in mouse fibroblasts (L929 cells), however, could be demonstrated only after inoculation of BHK-21 cells with the transfected L929 cells. Analysis of cellular and viral protein synthesis in mutant virus-infected cells showed a delayed inhibition of host cell protein synthesis and a reduced production of viral proteins. In a single-cycle infection, mutant virus produced only 1% of wild-type virus yield at 8 h postinfection. Host cell translation shutoff in L929 cells infected with mutant virus was restored by the addition of the kinase inhibitor 2-aminopurine. Mutant virus production in 2-aminopurine-treated L929 cells was increased to 60% of wild-type virus yield at 8 h postinfection. Our results suggest that the cardiovirus leader peptide is involved in the inhibition of host cell protein synthesis.
Insights
The cardiovirus leader peptide, unlike its aphthovirus counterpart, is crucial for inhibiting host cell protein synthesis. Deleting this leader peptide in mengovirus significantly reduced viral replication and delayed translation shutoff.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Picornaviruses possess leader peptides, but only Cardiovirus and Aphthovirus genera have them.
- Aphthovirus leader peptides function in viral polyprotein processing and host cell translation shutoff.
- The specific role of cardiovirus leader peptides remains largely unknown.
Purpose of the Study:
- To elucidate the function of the cardiovirus leader peptide.
- To investigate the role of the leader peptide in viral replication and host cell interaction.
Main Methods:
- Construction and characterization of a mengovirus leader peptide deletion mutant.
- Analysis of viral and cellular protein synthesis in infected cells.
- Assessment of viral growth kinetics in different cell lines (BHK-21 and L929).
- Evaluation of the effect of the kinase inhibitor 2-aminopurine on mutant virus production.
Main Results:
- The deletion mutant exhibited reduced growth rates in baby hamster kidney cells (BHK-21).
- Mutant virus production in mouse fibroblasts (L929 cells) was significantly impaired, requiring co-cultivation with BHK-21 cells.
- Infected cells showed delayed inhibition of host cell protein synthesis and reduced viral protein production.
- The kinase inhibitor 2-aminopurine partially restored host cell translation shutoff and increased mutant virus yield.
Conclusions:
- The cardiovirus leader peptide plays a significant role in inhibiting host cell protein synthesis.
- This inhibition is likely mediated through a pathway sensitive to the kinase inhibitor 2-aminopurine.
- The leader peptide is essential for efficient viral replication and propagation.