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Oligosyndactyly: a lethal mutation in the mouse that results in mitotic arrest very early in development

T Magnuson, C J Epstein

    Cell
    |October 1, 1984
    PubMed

    Insights

    The oligosyndactyly (Os) mutation causes developmental lethality in homozygous mice by arresting cells in mitosis. This unique mutation prevents chromosome movement from the metaphase plate despite normal mitotic spindles.

    Area of Science:

    • Developmental biology
    • Genetics
    • Cell biology

    Background:

    • The oligosyndactyly (Os) mutation in mice causes syndactyly, muscle anomalies, and diabetes insipidus in heterozygotes.
    • Homozygous Os mutations are lethal early in embryonic development.

    Purpose of the Study:

    • To define the molecular mechanism underlying the lethality of homozygous Os mutations.
    • To characterize the nature of the mitotic defect in homozygous Os embryos.

    Main Methods:

    • Analysis of homozygous embryos at the blastocyst stage.
    • Cytologic examination of mitotic spindles and chromosome behavior.

    Main Results:

    • Homozygous embryos arrest with cells accumulating in mitosis at the blastocyst stage.
    • Mitotic spindles appear normal, but chromosomes fail to move from the metaphase plate.
    • This represents the first defined mammalian developmental mutation causing a specific defect in chromosome segregation.

    Conclusions:

    • The Os mutation, in its homozygous state, disrupts chromosome segregation during mitosis.
    • This defect is unique among known mitotic arrest mutations in higher eukaryotes.
    • Os provides a novel model for studying chromosome movement and developmental lethality.

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