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Cytoskeleton-associated Pr65gag and assembly of retrovirus temperature-sensitive mutants in chronically infected

C A Edbauer, R B Naso

    Virology
    |April 30, 1984
    PubMed

    Insights

    Temperature-sensitive murine leukemia virus mutants show defects in virus assembly, accumulating the Pr65gag precursor protein. This core protein precursor preferentially associates with the cytoskeleton at nonpermissive temperatures, impacting retrovirus assembly.

    Area of Science:

    • Retroviruses
    • Molecular Virology
    • Cell Biology

    Background:

    • Murine leukemia virus (MuLV) assembly is crucial for viral replication.
    • Temperature-sensitive (ts) mutants provide insights into essential viral processes.
    • The Pr65gag precursor protein is central to MuLV core formation.

    Purpose of the Study:

    • To investigate the role of the Pr65gag precursor protein in MuLV assembly.
    • To determine the effect of nonpermissive temperatures on Pr65gag localization.
    • To elucidate the involvement of the cytoskeleton in retrovirus assembly.

    Main Methods:

    • Utilized temperature-sensitive mutants of MuLV.
    • Employed pulse-chase labeling and detergent extraction (Nonidet P-40) to analyze protein localization.
    • Fractionated cell extracts into cytoskeleton-enriched and soluble components.
    • Analyzed viral proteins using gel electrophoresis and immunoprecipitation.

    Main Results:

    • Specific MuLV ts mutants accumulated Pr65gag at nonpermissive temperatures (39°C).
    • Elevated Pr65gag levels were found in released virions at 39°C compared to permissive temperatures (33°C).
    • Pr65gag preferentially associated with the cytoskeleton-enriched fraction at 39°C in certain mutants, unlike others.

    Conclusions:

    • The association of Pr65gag with the cytoskeleton is critical for MuLV assembly and maturation.
    • Cytoskeletal interactions influence virus budding and post-budding development.
    • Defects in Pr65gag-cytoskeleton association lead to impaired retrovirus assembly.

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