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Anaphase delay after inhibition of protein synthesis between late prophase and prometaphase
Abstract:
The relationship between protein synthesis and mitosis was studied in Physarum polycephalum, a plasmodial slime mold whose nuclear divisions are synchronous. Results of studies with actidione (cycloheximide), an inhibitor of protein synthesis, indicated that the essential structural proteins for mitosis and nuclear reconstruction were completed prior to the dissolution of the nucleolus in prophase. Proteins that determine the duration of the transition from metaphase to nuclear reconstruction were synthesized from late prophase to prometaphase. It is proposed that these proteins are concerned with the transformation of chemical energy into the mechanical work of mitosis.
Insights
Protein synthesis is crucial for cell division in Physarum polycephalum. Essential mitotic proteins are made before nuclear envelope breakdown, while others regulate the metaphase to anaphase transition.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The cell cycle, particularly mitosis, requires precise protein synthesis.
- Physarum polycephalum offers a unique model due to its synchronous nuclear divisions.
Purpose of the Study:
- To investigate the temporal relationship between protein synthesis and mitosis in Physarum polycephalum.
- To identify specific proteins involved in different stages of mitosis and nuclear reconstruction.
Main Methods:
- Utilized actidione (cycloheximide), a protein synthesis inhibitor.
- Observed synchronous nuclear divisions in the plasmodial slime mold Physarum polycephalum.
- Analyzed protein synthesis timing relative to mitotic events like nucleolus dissolution and nuclear reconstruction.
Main Results:
- Essential structural proteins for mitosis and nuclear reconstruction are synthesized before prophase nucleolus breakdown.
- Proteins regulating the duration of the metaphase-to-anaphase transition are synthesized during late prophase and prometaphase.
- These regulatory proteins are hypothesized to convert chemical energy into the mechanical forces of mitosis.
Conclusions:
- Protein synthesis timing is critical for the successful progression of mitosis and nuclear reconstruction.
- Specific protein sets are required for structural integrity and temporal regulation of mitotic phases.
- The findings suggest a direct link between protein synthesis and the energy transduction required for chromosome segregation.