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Subnuclear localization of proteins encoded by the oncogene v-myb and its cellular homolog c-myb

K H Klempnauer, A E Sippel

    Molecular and Cellular Biology
    |January 1, 1986
    PubMed

    Insights

    The viral Myb protein (p45v-myb) and chicken Myb protein (p75c-myb) associate with both chromatin and the nuclear matrix. This suggests Myb proteins interact with multiple nuclear targets for their function.

    Area of Science:

    • Molecular Biology
    • Cell Biology
    • Virology

    Background:

    • The retroviral transforming gene v-myb encodes a nuclear protein (p45v-myb), a modified version of the chicken c-myb gene product (p75c-myb).
    • Both p45v-myb and p75c-myb are nuclear proteins, suggesting a role in nuclear functions.

    Purpose of the Study:

    • To determine the subnuclear locations of p45v-myb and p75c-myb.
    • To identify potential nuclear targets involved in v-myb-mediated cellular transformation and c-myb function.

    Main Methods:

    • Nuclear extraction using varying salt concentrations.
    • Assessment of DNA-binding activity.
    • Nuclease digestion and analysis of protein association with nuclear substructures.

    Main Results:

    • 80-90% of both p45v-myb and p75c-myb were released from nuclei at low salt concentrations and showed DNA-binding activity.
    • A minor fraction (10-20%) of both proteins remained tightly associated with nuclei even at high salt concentrations (2 M NaCl).
    • These proteins appear to associate with both chromatin and the nuclear matrix.

    Conclusions:

    • Both viral and cellular Myb proteins are associated with chromatin and the nuclear matrix.
    • Myb protein function likely involves interactions with multiple nuclear targets, including chromatin and the nuclear matrix.

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