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Possible involvement of putrescine in nucleolar formation in early embryos

O Heby, H Emanuelsson

    Cell and Tissue Research
    |November 9, 1978
    PubMed

    Insights

    Inhibiting putrescine synthesis in Ophryotrocha labronica eggs arrested development by preventing nuclei formation. This suggests putrescine is vital for nucleolar formation during gastrulation.

    Area of Science:

    • Developmental Biology
    • Cell Biology
    • Biochemistry

    Background:

    • Polychaete worms (Ophryotrocha labronica) are model organisms for studying early development.
    • Putrescine, a polyamine, is essential for cell growth and proliferation.
    • The precise role of putrescine in early embryonic development, particularly in nucleolar formation, remains unclear.

    Purpose of the Study:

    • To investigate the role of putrescine in the embryonic development of Ophryotrocha labronica.
    • To determine the effects of inhibiting putrescine synthesis on embryonic development and nucleolar formation.
    • To elucidate the potential involvement of putrescine in nuclear and nucleolar biogenesis.

    Main Methods:

    • Continuous treatment of developing Ophryotrocha labronica eggs with alpha-methylornithine to inhibit putrescine synthesis.
    • Ultrastructural analysis using electron microscopy to examine cellular morphology and development.
    • Electron-microscopical autoradiography with 3H-ornithine to trace putrescine synthesis and localization.

    Main Results:

    • Inhibition of putrescine synthesis led to developmental arrest at the gastrulation stage.
    • Ultrastructural analysis revealed a failure in nuclei formation in treated embryos.
    • Autoradiography showed intense labeling of nucleoli by newly synthesized putrescine during gastrulation, coinciding with peak endogenous synthesis.

    Conclusions:

    • Putrescine synthesis is essential for successful embryonic development in Ophryotrocha labronica, specifically for nuclei formation.
    • The findings strongly suggest a direct role for putrescine in the process of nucleolar formation.
    • Putrescine may be a critical factor in regulating nucleolar biogenesis during early embryonic development.

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