Related Experiment Video

Updated: Jun 29, 2025

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing
09:16

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing

Published on: October 11, 2015

11.7K

Loss of UBE2S causes meiosis I arrest with normal spindle assembly checkpoint dynamics in mouse oocytes

Si-Min Sun1,2,3,4, Bing-Wang Zhao1,2,3,4, Yuan-Yuan Li1,2,3

  • 1State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.

Development (Cambridge, England)
|March 28, 2024
PubMed

Insights

The E2 ubiquitin-conjugating enzyme UBE2S is crucial for mouse oocyte maturation and fertility. Its absence causes meiosis I arrest, affecting APC/C activity and leading to early embryonic death.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Reproductive Biology

Background:

  • Protein degradation via the ubiquitin-proteasome system is vital for cell cycle regulation.
  • The anaphase-promoting complex/cyclosome (APC/C) is a key E3 ubiquitin ligase controlling meiosis.
  • Ubiquitin-conjugating enzyme E2 S (UBE2S) is involved in ubiquitin delivery to APC/C, but its role in oocytes is unclear.

Purpose of the Study:

  • To investigate the function of UBE2S in mouse oocyte maturation and female fertility.
  • To elucidate the molecular mechanisms by which UBE2S influences meiotic progression.

Main Methods:

  • Generation and analysis of Ube2s knockout mice.
  • Microscopic examination of oocyte spindle assembly and checkpoint dynamics.
  • Assessment of APC/C activity and substrate levels (Cyclin B1, securin).
  • Fertilization and early embryonic development studies.

Main Results:

  • Ube2s-deleted oocytes exhibited meiosis I arrest with intact spindle assembly.
  • Absence of UBE2S impaired APC/C activity, leading to high levels of Cyclin B1 and securin.
  • Homologous chromosome separation failed in Ube2s-deficient oocytes.
  • Fertilized oocytes developed to implantation but arrested and died before embryonic day 10.5.

Conclusions:

  • UBE2S plays an indispensable role in regulating mouse oocyte meiosis.
  • UBE2S is essential for proper APC/C function, homologous chromosome separation, and female fertility.
  • Disruption of UBE2S function leads to early embryonic lethality.
Keywords:
APC/CMeiosis I arrestMouse oocytesSACUBE2S

More Related Videos

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes10:09

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes

Published on: September 13, 2022

2.0K
Author Spotlight: Understanding DNA Damage Response in Mammalian Oocytes and Preimplantation Embryos07:46

Author Spotlight: Understanding DNA Damage Response in Mammalian Oocytes and Preimplantation Embryos

Published on: June 23, 2023

2.3K

Related Concept Videos

Meiosis II02:02

Meiosis II

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,...
45.6K
Meiosis vs. Mitosis02:57

Meiosis vs. Mitosis

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...
55.5K
The Spindle Assembly Checkpoint02:19

The Spindle Assembly Checkpoint

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...
3.2K
Meiosis I01:49

Meiosis I

Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by...
193.5K
Separation of Sister Chromatids02:17

Separation of Sister Chromatids

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...
3.6K
Nondisjunction01:29

Nondisjunction

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
75.5K