Related Experiment Video

Updated: Sep 20, 2026

Multi-Photon Laser Ablation of Cytoplasmic Microtubule Organizing Centers in Mouse Oocytes
08:24

Multi-Photon Laser Ablation of Cytoplasmic Microtubule Organizing Centers in Mouse Oocytes

Published on: November 11, 2022

MAPK is involved in metaphase I arrest in oyster and mussel oocytes

Amelia Portillo-López1, Meredith C Gould, José Luis Stephano

  • 1Centro de Investigación Científica y de Educación Superior en Ensenada, Depto de Biotecnología, Km 107 carretera Tijuana-Ensenada, Ensenada, BC México.

Biology of the Cell
|August 28, 2003
PubMed

Insights

Active mitogen-activated protein kinase (MAPK) is essential for maintaining metaphase I arrest in oyster oocytes. However, other proteins are also required for this crucial meiotic process.

Area of Science:

  • Marine Biology
  • Developmental Biology
  • Cell Biology

Background:

  • Oocytes of oysters (Crassostrea gigas and Mytilus galloprovincialis) naturally arrest at metaphase I before fertilization.
  • Understanding the molecular mechanisms regulating this meiotic arrest is crucial for reproductive biology.

Purpose of the Study:

  • To investigate the role of mitogen-activated protein kinase (MAPK) in maintaining metaphase I arrest in oyster oocytes.
  • To determine if MAPK activity alone is sufficient for metaphase I arrest.

Main Methods:

  • Oocytes were treated with U0126, a MEK inhibitor, to block MAPK activity.
  • Chromosome behavior was assessed using bisbenzimide staining.
  • MAPK activity was measured using immunoblots with anti-phospho MAPK antibodies.
  • Protein synthesis inhibition was achieved using emetine.

Main Results:

  • U0126 treatment eliminated detectable active MAPK, leading to resumption of meiosis, polar body formation, and chromosome decondensation.
  • Oocytes treated with U0126 failed to arrest in metaphase I even when maturing spontaneously.
  • Emetine treatment also induced meiotic resumption, despite sustained MAPK activity, and reduced protein synthesis significantly.

Conclusions:

  • Active MAPK is necessary but not sufficient for maintaining metaphase I arrest in oyster oocytes.
  • Additional protein synthesis is required to sustain the metaphase I arrest.
  • This study highlights the complex regulatory network governing oocyte meiotic maturation.

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

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

Related Concept Videos

M-Cdk Drives Transition Into Mitosis02:15

M-Cdk Drives Transition Into Mitosis

Checkpoints throughout the cell cycle serve as safeguards and gatekeepers, allowing the cell cycle to progress in favorable conditions and slow or halt it in problematic ones. This regulation is known as the cell cycle control system.
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
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,...
Meiosis II02:23

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 containing...
Microtubule Associated Proteins (MAPs)01:42

Microtubule Associated Proteins (MAPs)

Microtubule function and architecture are regulated by an array of specialized proteins called microtubule-associated proteins or MAPs. These proteins are widespread across different organisms and have conserved protein motifs, like the multi-TOG domain for tubulin binding found in the CLASP family of MAPs. Some MAPs are lineage-specific based on their conserved domains. Their functions depend upon the cytoskeletal architecture and cell type they are located within. In-plant cells, a specific...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
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...