Related Experiment Video

Updated: Aug 3, 2026

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
07:03

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment

Published on: July 23, 2011

Regulation of mouse oocyte maturation: involvement of cyclic AMP phosphodiesterase and calmodulin

E A Bornslaeger, M W Wilde, R M Schultz

    Developmental Biology
    |October 1, 1984
    PubMed

    Insights

    Mouse oocyte phosphodiesterase (PDE) activity decreases cyclic adenosine monophosphate (cAMP) during meiosis resumption. Calmodulin (CaM) inhibitors suggest a CaM-dependent step, but not directly via CaM-modulated PDE, in this process.

    Area of Science:

    • Reproductive Biology
    • Cellular Signaling
    • Molecular Endocrinology

    Background:

    • A decrease in mouse oocyte cyclic adenosine monophosphate (cAMP) levels is linked to the resumption of meiosis.
    • The precise mechanisms regulating cAMP levels during oocyte maturation remain incompletely understood.
    • Cyclic nucleotide phosphodiesterases (PDEs) are key enzymes involved in cAMP degradation.

    Purpose of the Study:

    • To investigate the role of oocyte cyclic nucleotide phosphodiesterase (PDE) in the cAMP decrease during mouse oocyte maturation.
    • To explore the potential involvement of calmodulin (CaM) in regulating oocyte maturation and cAMP levels.

    Main Methods:

    • Assayed PDE activity in mouse oocyte extracts.
    • Utilized specific PDE inhibitors and calmodulin (CaM) inhibitors (trifluoperazine, calmidizolium, W7, W13) to assess their effects on germinal vesicle breakdown (GVBD).
    • Quantified CaM levels in oocytes using radioimmunoassay and assessed CaM-modulated PDE activity.

    Main Results:

    • Mouse oocyte extracts exhibited soluble PDE activity.
    • PDE inhibitors correlated positively with inhibition of both PDE activity and germinal vesicle breakdown (GVBD).
    • Calmodulin (CaM) inhibitors demonstrated a dose-dependent inhibition of GVBD, suggesting a CaM-dependent step in maturation.

    Conclusions:

    • Oocyte PDE is implicated in the cAMP decrease associated with meiotic resumption.
    • A CaM-dependent process influences oocyte maturation, potentially occurring concurrently with or after the cAMP drop.
    • The CaM-modulated PDE activity in oocytes does not appear to be the direct target of CaM inhibitors affecting maturation.

    More Related Videos

    Defining the Program of Maternal mRNA Translation during In vitro Maturation using a Single Oocyte Reporter Assay08:00

    Defining the Program of Maternal mRNA Translation during In vitro Maturation using a Single Oocyte Reporter Assay

    Published on: June 16, 2021

    Mouse Oocyte In Vitro Maturation, Fertilization, and Culture of Preimplantation Embryos09:24

    Mouse Oocyte In Vitro Maturation, Fertilization, and Culture of Preimplantation Embryos

    Published on: May 29, 2026

    Related Concept Videos

    Positive Regulator Molecules01:45

    Positive Regulator Molecules

    To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
    Positive Regulator Molecules02:39

    Positive Regulator Molecules

    Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
    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,...
    Feedback Regulation of Calcium Concentration01:27

    Feedback Regulation of Calcium Concentration

    Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
    Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
    Calmodulin-dependent Signaling01:16

    Calmodulin-dependent Signaling

    Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
    The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
    Oogenesis01:22

    Oogenesis

    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...