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The errors in assembly of MuLV in interferon treated cells
Abstract:
Interferon treatment of JLSV-6 cells chronically infected with Rauscher MuLV leads to the formation of noninfectious particles (interferon virions) containing the structural proteins of env and gag genes as well as additional viral polypeptides. In the control virions the major glycoprotein detected is gp71, interferon virions contain in addition to gp71 and 85k dalton (gp85) glucosamine-containing, fucose-deficient glycoprotein which is recognized by antiserum to MuLV but not by the gp71 antiserum. The surface iodination of the intact virions indicates that both gp71 and gp85 are the major components of the external virions envelope. However, unlike the control virions in which gp71 associates with p15E (gp90), the gp71-p15E complex was not detected in interferon virions. The analysis of the iodinated proteins of the disrupted interferon virions revealed the presence of 85k and 65k dalton polypeptides preciptable with antiserum against MuLV, which are not present in the control virions. The difference in the polypeptide pattern of virions produced in the presence of interferon does not seem to be a consequence of the slowdown in the synthesis of viral proteins or their processing in the interferon-treated cells. Both the structural proteins of env and gag genes seem to be synthesized and processed at a comparable rate in the interferon-treated and -untreated cells. These results indicate an alteration of virus assembly in the presence of interferon.
Insights
Interferon treatment alters Rauscher Murine Leukemia Virus (MuLV) assembly, producing noninfectious viral particles with altered protein composition. This suggests a modification in how viral components are put together in the presence of interferon.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Chronic infection with Rauscher Murine Leukemia Virus (MuLV) in JLSV-6 cells.
- Interferon (IFN) is known to have antiviral properties.
- Understanding the effects of IFN on viral particle production is crucial.
Purpose of the Study:
- To investigate the impact of interferon treatment on the production and composition of Rauscher MuLV particles.
- To identify alterations in viral proteins and their assembly in interferon-treated cells.
Main Methods:
- Treatment of chronically infected JLSV-6 cells with interferon.
- Analysis of viral particles (virions) produced.
- Surface iodination of intact virions.
- Immunoprecipitation with specific antisera against MuLV and viral proteins (gp71, p15E).
- Analysis of viral polypeptide patterns.
Main Results:
- Interferon treatment resulted in noninfectious viral particles (interferon virions).
- Interferon virions contained a novel glycoprotein (gp85) and lacked the gp71-p15E complex found in control virions.
- New polypeptides (85k and 65k daltons) were detected in disrupted interferon virions.
- Viral protein synthesis and processing rates were comparable in treated and untreated cells, indicating an assembly defect.
Conclusions:
- Interferon treatment induces significant alterations in Rauscher MuLV virion composition.
- The findings suggest a defect in viral assembly rather than viral protein synthesis or processing.
- Interferon influences the final assembly of viral particles, leading to the production of noninfectious virions.