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Mechanism of premature polypetide termination in a mouse ascites cell-free system programmed by encephalomyocarditis

L A Hunt

    Journal of Virology
    |May 1, 1976
    PubMed

    Insights

    This study analyzed encephalomyocarditis virus RNA-programmed polypeptide release in a cell-free system. Polypeptide release was independent of KCl concentration, with products found in both soluble and particulate fractions.

    Area of Science:

    • Molecular Biology
    • Virology

    Background:

    • Encephalomyocarditis virus (EMCV) replication involves the translation of a large precursor polyprotein.
    • Understanding the mechanisms of premature termination and release of viral polypeptides is crucial for comprehending viral replication strategies.

    Purpose of the Study:

    • To investigate the premature termination and release of encephalomyocarditis viral RNA-programmed polypeptides.
    • To analyze the characteristics of these released polypeptides and their association with cellular fractions.

    Main Methods:

    • Utilized a cell-free system derived from mouse ascites tumor cells.
    • Analyzed polypeptide products using molecular weight determination.
    • Fractionated products into soluble and particulate components.

    Main Results:

    • KCl concentration influenced the size distribution of translation products but not the overall extent of polypeptide release.
    • Major polypeptide products, ranging from 60,000 to 140,000 molecular weight, were identified in both soluble and particulate fractions.
    • The majority of released polypeptides existed as free proteins, while ribosome-bound products were predominantly in the form of peptidyl-tRNA.

    Conclusions:

    • Premature termination and release of EMCV polypeptides occur in a cell-free system.
    • The process is influenced by salt concentration regarding product size but not release extent.
    • Distinction between free protein and peptidyl-tRNA forms highlights different stages of translation termination and release.

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