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Published on: February 9, 2017
Temporal regulation of embryonic M-phases
Jacek Z Kubiak1, Franck Bazile, Aude Pascal
1CNRS/University of Rennes 1, Institute of Genetics & Development, Rennes cedex, France. jacek.kubiak@univ-rennes1.fr
Folia Histochemica Et Cytobiologica
|February 26, 2008
Summary
Cell cycle regulation differs between species. Researchers identified Translationally Controlled Tumor Protein (TCTP) as a key factor in Xenopus embryonic cell division, influencing mitosis duration and proliferation.
Area of Science:
- Cell Biology
- Developmental Biology
- Molecular Biology
Background:
- Temporal regulation of M-phases (mitosis) in the cell cycle is crucial and varies across cell types, especially during embryonic development.
- The first embryonic mitosis is notably longer than subsequent divisions, with distinct molecular mechanisms observed in different species like mice and Xenopus.
- Previous understanding suggested cyclin B degradation controlled M-phase inactivation, but new evidence points to dissociation from CDK1 in Xenopus.
Purpose of the Study:
- To investigate the differing mechanisms that prolong the first embryonic M-phase in mouse and Xenopus embryos.
- To identify novel proteins involved in proteasomal degradation during the first embryonic mitosis in Xenopus laevis.
- To characterize the role and expression of identified proteins, such as TCTP, in cell division across different species.
Main Methods:
- Comparative analysis of embryonic cell cycle M-phase duration in mice and Xenopus.
- Proteomic screening (two complementary screens) to identify ubiquitinated and proteasome-degraded proteins during early embryonic mitosis in Xenopus.
- Validation of identified proteins, including characterization of Translationally Controlled Tumor Protein (TCTP) expression and function.
Main Results:
- Mouse embryos exhibit a unique mechanism prolonging the first M-phase, distinct from Xenopus, involving an unknown factor similar to oocyte CSF.
- In Xenopus, elevated cyclin B levels contribute to M-phase prolongation without cell cycle arrest, and MPF inactivation depends on cyclin B/CDK1 dissociation, not degradation.
- Proteomic screens identified 175 proteins in the first screen and 9 novel candidates in the second, with TCTP showing partial degradation during mitosis and meiotic exit.
Conclusions:
- The mechanisms regulating the first embryonic M-phase are species-specific, highlighting evolutionary divergence in cell cycle control.
- TCTP is identified as a novel mitotic spindle protein in Xenopus, mouse, and human cells, positively regulating cellular proliferation.
- Further analysis of candidate proteins is ongoing to fully elucidate their roles in embryonic cell division.
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