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Updated: Jul 6, 2025
12:04
Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy
Published on: June 24, 2019
9.6K
Fission yeast Wee1 is required for stable kinetochore-microtubule attachment.
Masahiro Takado1, Takaharu G Yamamoto2, Yuji Chikashige2
1Radiation Biology Center, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan.
Open Biology
|January 3, 2024
Summary
Loss of Wee1 causes premature mitosis and unstable kinetochore attachment. Cells lacking Wee1 rely on the spindle checkpoint for viability, highlighting Wee1
Area of Science:
- Cell biology
- Molecular genetics
- Cancer research
Background:
- Wee1 is a key regulator of the cell cycle, inhibiting the G2/M transition by phosphorylating Cdk1/Cdc2.
- Loss of Wee1 function leads to an premature entry into mitosis.
- The spindle checkpoint is crucial for ensuring accurate chromosome segregation by preventing anaphase until all chromosomes are properly attached to the spindle.
Purpose of the Study:
- To investigate the viability defect observed in fission yeast cells lacking Wee1.
- To determine the role of the spindle checkpoint in the survival of Wee1-deficient cells.
- To elucidate the underlying mechanisms causing kinetochore-microtubule attachment instability in Wee1 mutants.
Main Methods:
- Genetic analysis of fission yeast ( *Schizosaccharomyces pombe* ) mutants.
- Live-cell imaging to observe kinetochore-microtubule dynamics and spindle checkpoint activity.
- Immunofluorescence to detect the localization of spindle checkpoint proteins like Mad2.
Main Results:
- Cells lacking Wee1 exhibit a requirement for a functional spindle checkpoint for viability, independent of the early mitotic entry.
- Live-cell imaging revealed that Wee1-deficient cells display unattached or improperly bioriented kinetochores.
- Mad2, a spindle checkpoint component, accumulates near the spindle, indicating checkpoint activation due to kinetochore attachment defects.
Conclusions:
- Wee1 plays a critical role in maintaining stable kinetochore-microtubule attachments during mitosis.
- The spindle checkpoint compensates for the lack of Wee1 by delaying mitosis, allowing time for proper kinetochore biorientation.
- These findings suggest Wee1's involvement in ensuring accurate chromosome segregation and provide a rationale for Wee1 inhibitors in cancer therapy.
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