Related Experiment Video
Updated: May 7, 2026
09:16
Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing
Published on: October 11, 2015
ING3 is essential for asymmetric cell division during mouse oocyte maturation
Shinnosuke Suzuki1, Yusuke Nozawa, Satoshi Tsukamoto
1Laboratory of Reproductive Biology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
Plos One
|September 26, 2013
Summary
Loss of ING3 (inhibitor of growth family, member 3) function in mouse oocytes disrupts asymmetric cell division and cortical reorganization, potentially via the mTOR pathway.
Area of Science:
- Cell Biology
- Developmental Biology
- Molecular Biology
Background:
- ING3 (inhibitor of growth family, member 3) is a NuA4 complex subunit involved in gene expression, cell cycle, and apoptosis in somatic cells.
- The function of ING3 in germ cells, particularly oocytes, is largely unknown.
- Asymmetric cell division is crucial for oocyte maturation and proper development.
Purpose of the Study:
- To investigate the role of ING3 in mouse oocyte maturation and asymmetric cell division.
- To determine the molecular mechanisms by which ING3 influences oocyte polarization and spindle migration.
- To explore the potential involvement of the mTOR pathway in ING3-mediated asymmetric division.
Main Methods:
- siRNA-mediated knockdown of Ing3 in mouse oocytes.
- Immunostaining to determine ING3 localization during oocyte maturation.
- Analysis of cell division patterns (symmetric vs. asymmetric).
- Assessment of actin cap and cortical granule-free domain formation.
- Quantitative RT-PCR to measure mRNA expression of key genes, including mTOR and its downstream targets.
Main Results:
- Loss of ING3 function resulted in symmetric cell division and failure of cortical reorganization in mouse oocytes.
- ING3 knockdown led to the absence of an actin cap and cortical granule-free domain, inhibiting spindle migration.
- ING3 localized to the germinal vesicle in GV oocytes and homogeneously in the cytoplasm after GVBD.
- mRNA expression analysis revealed downregulation of mTOR and its downstream effectors (Cdc42, Rac1, RhoA) in siIng3-injected oocytes.
Conclusions:
- ING3 is essential for establishing asymmetric cell division and cortical organization in mouse oocytes.
- ING3 may regulate asymmetric cell division through the mTOR signaling pathway.
- Disruption of ING3 function leads to developmental defects in oocytes, impacting their maturation process.
Related Concept Videos
02:02Meiosis 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,...
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,...
01:57Meiosis 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...
01:22Oogenesis
Oogenesis, the process of developing egg cells (female gametes), occurs within the ovaries and is fundamental to female fertility. This sequence begins during fetal development when diploid oogonia in the developing ovaries undergo mitotic divisions to produce primary oocytes. By birth, these primary oocytes enter prophase I of meiosis but become arrested in this stage, remaining suspended until puberty.
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
02:07Oogenesis
In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from the equivalent procedure of spermatogenesis in males. First, meiotic divisions during oogenesis are asymmetric, meaning that a large oocyte (containing most of the cytoplasm) and minor polar body are produced as a result of meiosis I, and again following meiosis II. Since only oocytes will go on to form embryos if fertilized, this unequal...
02:13Determining the Plane of Cell Division
Positioning the cell division plane is a critical step during development and cell differentiation, particularly during mitosis when the plane is essential for determining the size of the two daughter cells. The cell division plane is perpendicular to the plane of chromosome segregation, but different types of organisms have different cell division mechanisms to suit their morphology and function.
Animal cells
In animal cells, the cleavage furrow forms along the plane of cell division starting...
Animal cells
In animal cells, the cleavage furrow forms along the plane of cell division starting...
01:21Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers. Nondisjunction is common during anaphase I or anaphase II of meiosis. Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...