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Selective blockage of initiation of host protein synthesis in RNA-virus-infected cells
Abstract:
Poliovirus mRNA and mRNA transcribed from vesicular stomatitis virus and reovirus genomes efficiently direct protein synthesis in vivo under experimental conditions where the initiation of host protein synthesis is selectively blocked. The selective blockage of host peptide chain initiation after exposure to hypertonic medium indicates that the translation of viral mRNA is more efficiently initiated than is the translation of host mRNA. It further suggests that virus directed suppression of host protein synthesis could proceed by a mechanism involving a nonspecific decrease in the rate of peptide chain initiation. Exposure of infected cells to hypertonic medium provides a unique tool with which to study early events in the infectious cycle by permitting the efficient unmasking of virus-specific poly-peptide synthesis.
Insights
Viral mRNA efficiently directs protein synthesis by selectively blocking host initiation. This suggests viruses suppress host protein synthesis via decreased peptide chain initiation rates, aiding early infection study.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Host protein synthesis initiation is crucial for cellular function.
- Viruses often manipulate host cell machinery for replication.
- Understanding viral mRNA translation is key to antiviral strategies.
Purpose of the Study:
- To investigate the differential efficiency of viral versus host mRNA translation.
- To elucidate the mechanism of virus-induced suppression of host protein synthesis.
- To explore the utility of hypertonic medium in studying viral infection.
Main Methods:
- Utilizing hypertonic medium to selectively block host protein synthesis initiation in vivo.
- Comparing the translation efficiency of poliovirus, vesicular stomatitis virus, and reovirus mRNAs.
- Analyzing the impact of hypertonic stress on host and viral peptide chain initiation.
Main Results:
- Viral mRNAs (poliovirus, VSV, reovirus) efficiently direct protein synthesis when host initiation is blocked.
- Host peptide chain initiation is selectively inhibited by hypertonic medium.
- Viral mRNA translation initiation is more efficient than host mRNA translation initiation under these conditions.
Conclusions:
- Viral translation is favored over host translation during infection, likely due to a nonspecific decrease in host peptide chain initiation.
- Hypertonic medium serves as a valuable tool for studying early viral infection events and viral polypeptide synthesis.