Related Experiment Video
Updated: Sep 10, 2025
Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing
Published on: October 11, 2015
MRE11 orchestrates porcine oocyte meiotic progression by modulating the spindle assembly checkpoint
Dandan Zhang1, Zaishan Yang2, Yongteng Zhang2
1Department of Reproductive Medicine, General Hospital of Wanbei Coal Group, Suzhou, China.
Introduction:
Mre11 is a multisubunit nuclease involved in DNA repair, and its dysfunction often causes DNA damage sensitivity, genomic instability, telomere shortening, and aberrant meiosis. However, the specific roles of Mre11 in porcine oocyte meiosis remain unclear.
Methods:
In this study, porcine oocytes were treated with the Mre11-specific inhibitor mirin to investigate the function of Mre11 during meiotic maturation. Meiotic progression, spindle and chromosome structure, spindle migration, cytoplasmic actin polymerization, and DNA damage levels were assessed using immunofluorescence and relevant molecular markers including BubR1 and γH2A.X.
Results:
Inhibition of Mre11 activity led to failure of first polar body extrusion, with sustained BubR1 presence at kinetochores, indicating activation of the spindle assembly checkpoint (SAC). Mre11-inhibited oocytes showed disrupted spindle and chromosome organization due to decreased microtubule stability. Additionally, spindle migration to the oocyte cortex was impaired, correlating with reduced cytoplasmic actin polymerization. Elevated DNA damage levels were observed in treated oocytes as evidenced by increased γH2A.X staining.
Discussion:
These findings demonstrate that Mre11 is essential for porcine oocyte meiotic progression by maintaining normal spindle assembly, actin cytoskeleton dynamics, and SAC activity. DNA damage accumulation following Mre11 inhibition likely contributes to meiotic failure, highlighting its critical role in ensuring oocyte quality.
Insights
Mre11 is crucial for porcine oocyte meiosis, ensuring proper spindle assembly, DNA repair, and cell division. Its inhibition causes meiotic failure and DNA damage, impacting oocyte quality.
Area of Science:
- Reproductive biology
- Molecular genetics
- Cell biology
Background:
- Mre11 nuclease is vital for DNA repair and genomic stability.
- Mre11 dysfunction leads to DNA damage sensitivity and meiotic errors.
- The precise role of Mre11 in porcine oocyte meiosis is not well understood.
Purpose of the Study:
- To investigate the function of Mre11 during porcine oocyte meiotic maturation.
- To determine the effects of Mre11 inhibition on key meiotic processes.
Main Methods:
- Porcine oocytes were treated with the Mre11-specific inhibitor mirin.
- Immunofluorescence and molecular markers (BubR1, γH2A.X) were used to assess meiotic progression, spindle and chromosome structure, spindle migration, actin polymerization, and DNA damage.
Main Results:
- Mre11 inhibition caused failure of first polar body extrusion and activated the spindle assembly checkpoint (SAC).
- Disrupted spindle and chromosome organization, impaired spindle migration, and reduced cytoplasmic actin polymerization were observed.
- Elevated DNA damage levels, indicated by increased γH2A.X staining, were detected in Mre11-inhibited oocytes.
Conclusions:
- Mre11 is essential for normal meiotic progression in porcine oocytes.
- Mre11 maintains spindle assembly, actin dynamics, and SAC activity.
- DNA damage accumulation due to Mre11 inhibition contributes to meiotic failure and compromised oocyte quality.
Related Concept Videos
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...
02:02Meiosis 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,...
02:57Meiosis vs. Mitosis
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
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...
03:09Meiosis I
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...
02:17Separation of Sister Chromatids
At the onset of anaphase, separase, a proteolytic enzyme, is...