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Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast
Published on: February 20, 2017
Variable pathways for developmental changes of mitosis and cytokinesis in Physarum polycephalum
L Solnica-Krezel1, T G Burland, W F Dove
1McArdle Laboratory for Cancer Research, Madison, Wisconsin 53706.
The Journal of Cell Biology
|May 1, 1991
Summary
The amebal-plasmodial transition in Physarum polycephalum involves a shift from astral to anastral mitosis, which is key to omitting cell division and forming a multinucleate plasmodium. This transition is independent of the decision to enter mitosis.
Area of Science:
- Cell Biology
- Developmental Biology
- Mycology
Background:
- Myxomycetes undergo a complex developmental process called the amebal-plasmodial transition (APT).
- This transition involves a shift in cell division from open, astral mitosis in uninucleate amoebae to intranuclear, anastral mitosis in multinucleate plasmodia.
- Cytokinesis is omitted during the formation of the plasmodium.
Purpose of the Study:
- To investigate the reorganization of mitotic spindles during the APT in Physarum polycephalum.
- To understand the relationship between mitotic spindle organization, tubulin isotype changes, and cytokinesis during this developmental process.
- To determine the role of mitotic spindle changes in the omission of cytokinesis.
Main Methods:
- Immunofluorescence microscopy was used to study mitotic spindle organization.
- Tubulin isotype expression (alpha 3-tubulin and beta 2-tubulin) was analyzed.
- Cytokinetic furrow formation was observed during different stages of mitosis.
Main Results:
- Mitotic spindle reorganization begins in committed uninucleate cells and is completed by the binucleate stage.
- Cells exhibited amebal, plasmodial, or chimeric mitotic spindle types, with some forming novel star microtubular arrays.
- Changes in alpha 3-tubulin and beta 2-tubulin levels were insufficient to explain spindle reorganization.
- Astral mitoses (amebal, chimeric) were often associated with cytokinetic furrows, while anastral plasmodial mitoses lacked furrows.
- Some cells with astral or chimeric mitoses showed incomplete furrowing, suggesting potential division failure.
Conclusions:
- The transition from astral to anastral mitosis appears sufficient to cause the omission of cytokinesis during the APT.
- Astral mitosis does not guarantee cytokinesis; incomplete furrowing can lead to failed division.
- Committed uninucleate cells with amebal or chimeric mitosis may either divide or form binucleate cells.
- Uninucleate cells with plasmodial-type spindles exclusively produce binucleate cells.
- The decision to initiate mitosis post-commitment is independent of changes in spindle organization and cytokinesis.
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