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Brefeldin A inhibits vaccinia virus envelopment but does not prevent normal processing and localization of the
D Ulaeto1, D Grosenbach, D E Hruby
1Department of Microbiology, Oregon State University, Corvallis 97331-3804.
Abstract:
The fungal metabolite Brefeldin A was found to inhibit the production of the infectious enveloped form of vaccinia virus, although production of the infectious intracellular form was not affected. Electron microscopic analysis and caesium chloride density centrifugation of progeny virions indicates that the drug block is not due to retention and accumulation of enveloped virions within the cell. Biochemical analysis of the candidate envelopment receptor for vaccinia virus, viral protein P37, shows that the drug has no discernible effect on palmitylation of this protein and does not prevent or alter its association with intracellular membranes. This suggests that P37 may not in fact be the receptor on intracellular membranes for vaccinia virus envelopment, and leaves open the question of what function this molecule performs in the envelopment process. 24AI 20563
Insights
Brefeldin A inhibits the release of infectious enveloped vaccinia virus. This drug does not affect intracellular virus production or the palmitylation of viral protein P37, suggesting P37 is not the envelopment receptor.
Area of Science:
- Virology
- Cell Biology
- Mycology
Background:
- Vaccinia virus (VACV) is a large DNA virus used as a model for studying enveloped virus assembly.
- Viral envelopment is a critical step for the release of infectious virions.
- The precise mechanism and cellular receptors involved in VACV envelopment remain incompletely understood.
Purpose of the Study:
- To investigate the effect of the fungal metabolite Brefeldin A (BFA) on vaccinia virus production.
- To elucidate the stage of viral replication affected by BFA.
- To examine the role of viral protein P37 in BFA-mediated inhibition of vaccinia virus envelopment.
Main Methods:
- Treatment of infected cells with Brefeldin A.
- Analysis of viral progeny using electron microscopy and cesium chloride density gradient centrifugation.
- Biochemical assays to assess protein palmitylation and membrane association.
Main Results:
- Brefeldin A inhibited the production of infectious enveloped vaccinia virus but not intracellular infectious virus.
- Electron microscopy and density centrifugation ruled out virion retention within the cell.
- BFA did not affect the palmitylation or membrane association of viral protein P37.
Conclusions:
- Brefeldin A blocks vaccinia virus envelopment at a post-assembly stage, prior to release.
- Viral protein P37 is unlikely to be the cellular receptor mediating vaccinia virus envelopment.
- The function of P37 in the envelopment process requires further investigation.