A degron-based approach to manipulate Eomes functions in the context of the developing mouse embryo

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Eomesodermin (Eomes), also known as Tbr2, is a T-box transcription factor vital for early mouse embryonic development.
• Eomes is required for implantation, anterior-posterior axis specification, and the epithelial-to-mesenchymal transition (EMT) of nascent mesoderm.
• Its precise roles in specifying diverse progenitor cell populations during gastrulation remain incompletely understood.

Purpose of the Study:

• To develop a tool for temporal control of Eomesodermin (Eomes) protein levels in embryonic stem cells and embryos.
• To investigate the functional roles of Eomes in various cell lineages during early development.
• To establish a system for dissecting Eomes-dependent processes through inducible degradation and cell marking.

Main Methods:

• Generation of a homozygous Eomes degron-tagged (dTAG) mouse model with an mCherry reporter.
• In vitro studies using embryonic stem cells to assess protein degradation and functional rescue.
• In utero administration of the dTAG ligand to evaluate in vivo protein degradation dynamics and lineage-specific effects.

Main Results:

• The degron-tagged Eomes protein is fully functional, and its degradation in vitro recapitulates Eomes-null phenotypes.
• In vivo dTAG treatment shows variable and lineage-specific Eomes degradation, reflecting dynamic expression patterns.
• Eomes protein levels rapidly recover upon dTAG ligand washout, demonstrating temporal control.

Conclusions:

• The developed Eomes-dTAG-mCherry system provides a powerful method for temporally manipulating Eomes protein activity.
• This tool enables detailed investigation of Eomes-dependent cell fate specification and developmental processes.
• The findings facilitate a deeper understanding of molecular mechanisms governing Eomes function in early embryogenesis.