Related Experiment Video
Updated: Oct 3, 2025
10:09
Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
2.2K
Kinetochore scaffold 1 regulates SAC function during mouse oocyte meiotic maturation
Wei Yue1,2, Yue Wang3, Tie-Gang Meng1
1State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Summary
Kinetochore scaffold 1 (KNL1) is crucial for accurate chromosome segregation during mouse oocyte meiosis. Depleting KNL1 disrupts the spindle assembly checkpoint (SAC), leading to aneuploid eggs and premature cell division.
Area of Science:
- Cell Biology
- Reproductive Biology
- Genetics
Background:
- Accurate chromosome segregation during oocyte meiosis is vital for mammalian reproduction.
- The spindle assembly checkpoint (SAC) ensures proper chromosome attachment to the spindle microtubules.
- Kinetochores are critical structures that mediate spindle-microtubule interactions and SAC regulation.
Purpose of the Study:
- To investigate the role of kinetochore scaffold 1 (KNL1) in regulating the SAC during mouse oocyte meiosis.
- To determine the impact of KNL1 depletion on chromosome segregation and meiotic progression.
Main Methods:
- KNL1 localization analysis in mouse oocytes.
- KNL1 depletion using small interfering RNA (siRNA) microinjection.
- Assessment of meiotic progression, spindle assembly checkpoint (SAC) function, and chromosome alignment.
Main Results:
- KNL1 localizes to kinetochores throughout oocyte meiotic maturation.
- KNL1 depletion leads to premature anaphase entry and aneuploidy.
- KNL1 deficiency results in premature SAC silencing, unstable kinetochore-microtubule attachments, and chromosome misalignment.
- KNL1 and MPS1 show a synergistic effect on SAC activation and maintenance.
Conclusions:
- KNL1 acts as a kinetochore platform protein essential for stabilizing the SAC.
- KNL1 ensures timely anaphase entry and accurate chromosome segregation in maturing oocytes.
- Disruption of KNL1 function compromises reproductive success by producing aneuploid eggs.
Related Concept Videos
02:02Meiosis II
47.1K
Meiosis II entails cell division and segregation of the sister chromatids, resulting in the production of four unique haploid gametes. The steps for meiosis II are similar to mitosis, except that meiosis II occurs in haploid cells, whereas mitosis occurs in diploid cells.
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,...
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,...
47.1K
02:19The Spindle Assembly Checkpoint
3.3K
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
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...
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...
3.3K
02:57Meiosis vs. Mitosis
59.6K
Cell division is necessary for growth and reproduction in organisms. Mitosis aids cell growth and development by dividing somatic cells. In contrast, meiosis causes the division of germ cells and plays an essential role in sexual reproduction. Due to their unique functional requirements, mitosis and meiosis differ from each other in multiple aspects.
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
59.6K
02:57Attachment of Sister Chromatids
3.5K
As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules. Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall...
3.5K
02:17Separation of Sister Chromatids
3.8K
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
3.8K
02:50Spindle Assembly
3.8K
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
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...
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...
3.8K