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Cyclin-dependent kinase control of centrosome duplication
K R Lacey1, P K Jackson, T Stearns
1Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA.
Summary
Centrosome duplication in Xenopus embryos requires cyclin/cdk2 kinase activity. Inhibiting this kinase blocks duplication, linking cell cycle events to centrosome duplication.
Area of Science:
- Cell Biology
- Molecular Biology
- Developmental Biology
Background:
- Centrosomes are critical for cell division, ensuring the correct number of centrosomes per cell.
- Centrosome duplication must be tightly regulated and coupled with the nuclear cell cycle to prevent errors.
Purpose of the Study:
- To investigate the molecular mechanisms regulating centrosome duplication in Xenopus laevis.
- To determine the role of cyclin/cdk2 kinase activity in centrosome duplication and centriole separation.
Main Methods:
- In vivo assays using Xenopus laevis embryos.
- In vitro assays using Xenopus egg extracts.
- Use of cyclin-dependent kinase (cdk) inhibitors p21 and p27.
- Depletion of cdk2, cyclin A, and cyclin E.
Main Results:
- Centrosome duplication in Xenopus embryos requires cyclin/cdk2 kinase activity.
- Inhibiting cdk2 with p21 or p27 blocked centrosome duplication in vivo.
- In vitro centriole separation activity was dependent on cyclin/cdk2.
- Centriole separation was inhibited by the mitotic state.
Conclusions:
- Cyclin/cdk2 kinase activity is essential for centrosome duplication in Xenopus.
- The cell cycle machinery, specifically cyclin/cdk2, regulates centrosome duplication.
- Inhibition of centriole separation during mitosis suggests a mechanism for periodic duplication.