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Updated: Apr 19, 2026
Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy
Published on: June 24, 2019
Meiotic nuclear movements in fission yeast are regulated by the transcription factor Mei4 downstream of a
Kun Ruan1, Takaharu G Yamamoto, Haruhiko Asakawa
1Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.
Abstract:
In meiosis, the fission yeast nucleus displays an elongated morphology, moving back and forth within the cell; these nuclear movements continue for approximately 2 h before meiotic nuclear divisions. Meiotic DNA replication occurs in an early phase of the nuclear movements and is followed by meiotic prophase. Here we report that in mutants deficient in meiotic DNA replication, the duration of nuclear movements is strikingly prolonged to four to 5 h. We found that this prolongation was caused by the Cds1-dependent replication checkpoint, which represses expression of the mei4(+) gene encoding a meiosis-specific transcription factor. In the absence of Mei4, nuclear movements persisted for more than 8 h. In contrast, overproduction of Mei4 accelerated termination of nuclear movements to approximately 30 min. These results show that Mei4 is involved in the termination of nuclear movements and that Mei4-mediated regulatory pathways link a DNA replication checkpoint to the termination of nuclear movements.
Insights
Meiotic DNA replication mutants prolong nuclear movements in fission yeast. This is due to a replication checkpoint that represses Mei4, a key protein regulating nuclear movement termination.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- During meiosis, fission yeast nuclei elongate and move for ~2 hours before division.
- Meiotic DNA replication precedes meiotic prophase and nuclear movements.
Purpose of the Study:
- To investigate the regulation of nuclear movement duration during fission yeast meiosis.
- To identify factors that control the termination of meiotic nuclear movements.
Main Methods:
- Analysis of nuclear movement duration in wild-type and mutant fission yeast strains.
- Investigating the role of the Cds1-dependent replication checkpoint.
- Assessing the impact of mei4(+) gene expression and Mei4 protein levels.
Main Results:
- Mutants deficient in meiotic DNA replication showed prolonged nuclear movements (4-5 hours).
- The Cds1-dependent replication checkpoint prolonged movements by repressing mei4(+) gene expression.
- Absence of Mei4 resulted in nuclear movements exceeding 8 hours, while Mei4 overproduction shortened them to 30 minutes.
Conclusions:
- Mei4 is crucial for terminating meiotic nuclear movements in fission yeast.
- Mei4-mediated pathways link the DNA replication checkpoint to the termination of nuclear movements.
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