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Updated: Jul 14, 2026
Chromatin Immunoprecipitation Assay for Tissue-specific Genes using Early-stage Mouse Embryos
Published on: April 29, 2011
Involvement of protein kinase B/AKT in early development of mouse fertilized eggs
Chen Feng1, Aiming Yu, Ying Liu
1Department of Biochemical and Molecular Biology, China Medical University, Shenyang 110001, Liaoning, China.
Abstract:
The activation of AKT (also called protein kinase B) is thought to be a critical step in the phosphoinositide 3-kinase pathway that regulates cell growth and differentiation. In this report, we investigated the role of AKT in the regulation of mouse early embryo development. Injection of mRNA coding for a constitutively active myristoylated AKT (myr-Akt1) into one-cell stage fertilized eggs induced cell division more effectively than injection of wild-type AKT (Akt1-WT) mRNA, whereas microinjection of mRNA of kinase-deficient AKT (Akt1-KD) delayed the first mitotic division. Meanwhile, microinjection of different kinds of mRNA of AKT affected the phosphorylation status of CDC2A-Tyr15 and the activation of M-phase promoting factor (MPF). To investigate the intermediate factor between AKT and MPF, we then injected one-cell stage eggs first with Akt1-WT mRNA or myr-Akt1 mRNA and then with mRNA encoding either wild-type CDC25B (Cdc25b-WT) or a AKT-nonphosphorylatable Ser351 to Ala CDC25B mutant (Cdc25b-S351A). Cdc25b-S351A strongly inhibited the effect of AKT. Therefore, AKT causes the activation of MPF and strongly promotes the development of one-cell stage mouse fertilized eggs by inducing AKT-dependent phosphorylation of CDC25B, a member of the CDC25 phosphatase family. Our finding that CDC25B acts as a potential target of AKT provides new insight into the effect of AKT in the regulation of early development of mouse embryos.
Insights
The protein kinase B (AKT) pathway promotes early mouse embryo development by activating M-phase promoting factor (MPF). AKT achieves this by phosphorylating CDC25B, a key phosphatase, which is crucial for cell division and embryonic growth.
Area of Science:
- Cell Biology
- Developmental Biology
- Molecular Biology
Background:
- The phosphoinositide 3-kinase (PI3K) pathway, regulated by AKT (protein kinase B), is vital for cell growth and differentiation.
- Understanding AKT's role in early embryonic development is crucial for reproductive biology and developmental research.
Purpose of the Study:
- To investigate the specific role of AKT in regulating early mouse embryo development.
- To elucidate the molecular mechanisms by which AKT influences embryonic cell division and progression.
Main Methods:
- Microinjection of various AKT variants (constitutively active myr-Akt1, wild-type Akt1-WT, kinase-deficient Akt1-KD) mRNA into one-cell stage mouse fertilized eggs.
- Analysis of cell division, mitotic progression, and phosphorylation status of CDC2A-Tyr15.
- Investigation of M-phase promoting factor (MPF) activation.
- Co-injection experiments with AKT and CDC25B variants (Cdc25b-WT, Cdc25b-S351A) to identify intermediate factors.
Main Results:
- Constitutively active myr-Akt1 enhanced cell division, while kinase-deficient Akt1-KD delayed it.
- AKT activation modulated CDC2A-Tyr15 phosphorylation and MPF activity.
- The CDC25B phosphatase, specifically its AKT-dependent phosphorylation site (Ser351), was identified as a critical intermediate.
- A mutant CDC25B (Cdc25b-S351A) significantly inhibited AKT's developmental effects.
Conclusions:
- AKT activation is essential for promoting early mouse embryo development.
- AKT promotes embryonic development by activating MPF through the phosphorylation of CDC25B.
- CDC25B is a direct downstream target of AKT in the context of early embryonic development, providing new insights into developmental regulation.
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