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Protein synthesis initiation factor modifications during viral infections: implications for translational control
1School of Pharmacy, University of Southern California, Los Angeles 90033.
Electrophoresis
|March 1, 1990
Summary
Viral infections can halt host cell protein synthesis. This study found that only reovirus and adenovirus infections moderately increased eukaryotic initiation factor 2 alpha phosphorylation, with no significant changes observed in other initiation factors or p220 cleavage across various viruses.
Area of Science:
- Molecular Biology
- Virology
- Cell Biology
Background:
- Viral infections often disrupt host cell functions, including protein synthesis.
- Translational repression is a key viral strategy, but the underlying molecular mechanisms vary.
- Eukaryotic initiation factors (eIFs) play critical roles in regulating protein synthesis.
Purpose of the Study:
- To investigate the correlation between modifications of initiation factor proteins and translational repression in virus-infected cells.
- To determine which specific initiation factors are affected by infection with various viruses.
- To identify conserved or divergent mechanisms of translational control during viral infection.
Main Methods:
- Two-dimensional gel electrophoresis was used to analyze protein modifications.
- Immunoblotting was employed to detect specific initiation factor proteins.
- Analysis was performed on cell lysates from tissue culture cells infected with multiple distinct viruses.
Main Results:
- Moderate increases in eukaryotic initiation factor (eIF)-2 alpha phosphorylation were observed in reovirus- and adenovirus-infected cells.
- Vesicular stomatitis virus, vaccinia virus, frog virus III, rhinovirus, and encephalomyocarditis virus did not significantly increase eIF-2 alpha phosphorylation.
- No significant changes were detected in eIF-4A, eIF-4B, or eIF-2 beta, nor was the cleavage of eIF-4F subunit p220 observed in cells infected by the analyzed viruses.
Conclusions:
- The shutoff of host cell protein synthesis during viral infection is not universally mediated by significant eIF-2 alpha phosphorylation or p220 cleavage.
- Specific viruses like reovirus and adenovirus induce distinct modifications in initiation factors, suggesting virus-specific mechanisms of translational control.
- The absence of widespread changes in key initiation factors indicates complex and varied strategies employed by viruses to manipulate host translation.