Related Experiment Video

Updated: Dec 22, 2025

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
10:09

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes

Published on: September 13, 2022

2.4K

Cyclin A1 in Oocytes Prevents Chromosome Segregation And Anaphase Entry

Lenka Radonova1,2, Tereza Pauerova1,2, Denisa Jansova2

  • 1Central European Institute of Technology, Department of Genetics and Reproduction, Veterinary Research Institute, Brno, Czech Republic.

Scientific Reports
|May 6, 2020
PubMed

Insights

Cyclin A1 is crucial for male meiosis but detrimental to female meiosis. Its persistent expression in oocytes causes cell cycle arrest, highlighting distinct APC/C functions in oocytes versus early embryos.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Genetics

Background:

  • Two cyclin A family members, cyclin A2 and cyclin A1, exist in various species.
  • Cyclin A2 is vital for cell division processes like DNA replication and mitosis.
  • Cyclin A1 expression is restricted to specific cells, with its role less understood.

Purpose of the Study:

  • To investigate the specific role and impact of cyclin A1 in female meiosis.
  • To determine if cyclin A1 expression is detrimental in oocytes.
  • To elucidate the mechanism behind cyclin A1-induced cell cycle arrest in oocytes.

Main Methods:

  • Gene deletion studies to assess cyclin A1's necessity in meiosis.
  • Analysis of cyclin A1 expression patterns in oocytes and early embryos.
  • Investigation of the anaphase-promoting complex/cyclosome (APC/C) and proteasome activity in relation to cyclin A1.

Main Results:

  • Cyclin A1 is essential for male meiosis but not female meiosis.
  • Oocyte-specific expression of cyclin A1 leads to cell cycle arrest before anaphase.
  • The APC/C and proteasome in oocytes fail to degrade cyclin A1 efficiently, inhibiting separase.
  • Cyclin A1 does not affect cell cycle progression in early embryos.

Conclusions:

  • Cyclin A1 is a critical cell cycle regulator with distinct roles in male and female germline meiosis.
  • Persistent cyclin A1 expression in oocytes causes a unique anaphase arrest, indicating fundamental differences in APC/C function between oocytes and early embryos.
  • Cyclin A1's presence is undesirable in oocytes, impacting female meiosis outcomes.

More Related Videos

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing09:16

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing

Published on: October 11, 2015

12.1K
Chromatin Spread Preparations for the Analysis of Mouse Oocyte Progression from Prophase to Metaphase II10:39

Chromatin Spread Preparations for the Analysis of Mouse Oocyte Progression from Prophase to Metaphase II

Published on: February 26, 2018

16.3K

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,...
48.8K
Meiosis II01:57

Meiosis II

Meiosis II is the second and final stage of meiosis. It relies on the haploid cells produced during meiosis I, each of which contain only 23 chromosomes—one from each homologous initial pair. Importantly, each chromosome in these cells is composed of two joined copies, and when these cells enter meiosis II, the goal is to separate such sister chromatids using the same microtubule-based network employed in other division processes. The result of meiosis II is two haploid cells, each...
205.7K
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...
4.2K
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
3.3K
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...
3.6K
The Cell Cycle Control System01:28

The Cell Cycle Control System

The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and...
5.1K