Related Experiment Video
Updated: Mar 31, 2026
Use of Time-Lapse Microscopy and Stage-Specific Nuclear Depletion of Proteins to Study Meiosis in S. cerevisiae
Published on: October 11, 2022
Nup132 modulates meiotic spindle attachment in fission yeast by regulating kinetochore assembly
Hui-Ju Yang1, Haruhiko Asakawa1, Tokuko Haraguchi2
1Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
Abstract:
During meiosis, the kinetochore undergoes substantial reorganization to establish monopolar spindle attachment. In the fission yeast Schizosaccharomyces pombe, the KNL1-Spc7-Mis12-Nuf2 (KMN) complex, which constitutes the outer kinetochore, is disassembled during meiotic prophase and is reassembled before meiosis I. Here, we show that the nucleoporin Nup132 is required for timely assembly of the KMN proteins: In the absence of Nup132, Mis12 and Spc7 are precociously assembled at the centromeres during meiotic prophase. In contrast, Nuf2 shows timely dissociation and reappearance at the meiotic centromeres. We further demonstrate that depletion of Nup132 activates the spindle assembly checkpoint in meiosis I, possibly because of the increased incidence of erroneous spindle attachment at sister chromatids. These results suggest that precocious assembly of the kinetochores leads to the meiosis I defects observed in the nup132-disrupted mutant. Thus, we propose that Nup132 plays an important role in establishing monopolar spindle attachment at meiosis I through outer kinetochore reorganization at meiotic prophase.
Insights
The nucleoporin Nup132 is crucial for organizing the outer kinetochore during meiosis in fission yeast. Its absence causes premature kinetochore assembly, leading to spindle assembly checkpoint activation and meiosis I defects.
Area of Science:
- Cell Biology
- Genetics
- Molecular Biology
Background:
- Meiosis requires precise kinetochore-spindle interactions for accurate chromosome segregation.
- The KNL1-Spc7-Mis12-Nuf2 (KMN) complex is essential for outer kinetochore function.
- KMN complex disassembly and reassembly are critical events during meiotic prophase.
Purpose of the Study:
- To investigate the role of nucleoporin Nup132 in the reorganization of the outer kinetochore during meiosis.
- To understand how Nup132 influences the assembly timing of KMN complex proteins.
- To determine the consequences of Nup132 depletion on meiotic progression and spindle attachment.
Main Methods:
- Utilized the fission yeast Schizosaccharomyces pombe as a model organism.
- Employed genetic disruption (nup132-disrupted mutant) to study Nup132 function.
- Observed kinetochore protein localization and spindle assembly checkpoint activity during meiosis.
Main Results:
- Nup132 is required for the timely assembly of the KMN complex proteins Mis12 and Spc7.
- In nup132-disrupted cells, Mis12 and Spc7 assemble precociously at centromeres during meiotic prophase.
- Depletion of Nup132 leads to spindle assembly checkpoint activation in meiosis I, suggesting erroneous spindle attachment.
Conclusions:
- Nup132 regulates the timing of outer kinetochore assembly during meiotic prophase.
- Precocious kinetochore assembly due to Nup132 absence causes meiosis I defects.
- Nup132 is vital for establishing proper monopolar spindle attachment through kinetochore reorganization.
Related Concept Videos
02:57Attachment of Sister Chromatids
02:02Meiosis II
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
02:19The Spindle Assembly Checkpoint
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
02:50Spindle Assembly
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
02:11Forces Acting on Chromosomes
Microtubules and motor proteins exert two types of forces on...
02:27The Mitotic Spindle
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...