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Mesp2 initiates somite segmentation through the Notch signalling pathway.
Y Takahashi1, K Koizumi, A Takagi
1Cellular & Molecular Toxicology Division, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan.
Nature Genetics
|August 10, 2000
Summary
Mesp2 controls rostro-caudal polarity in somites by regulating two Notch-signalling pathways. It suppresses Dll1 expression in the rostral somite, while presenilin-1 (Ps1) induces Dll1 in the caudal somite, establishing polarity.
Area of Science:
- Developmental biology
- Molecular genetics
- Cell signalling
Background:
- The Notch-signalling pathway is crucial for metameric pattern formation during somitogenesis.
- Genetic defects in Mesp2 or presenilin-1 (Ps1) lead to distinct vertebral phenotypes (caudalized vs. rostralized).
Purpose of the Study:
- To elucidate the molecular mechanisms governing rostro-caudal polarity establishment in somites.
- To investigate the roles of Mesp2 and Ps1 in regulating Notch signalling and Dll1 expression.
Main Methods:
- Genetic analysis in mice.
- Focus on the expression patterns of Notch ligand Dll1.
- Investigating the interplay between Mesp2, Ps1, and Notch signalling.
Main Results:
- Mesp2 initiates rostro-caudal polarity by modulating two Notch-signalling pathways.
- Mesp2 activates a Ps1-independent pathway to suppress Dll1 in the rostral somite.
- Ps1-mediated Notch signalling induces Dll1 expression in the caudal somite.
Conclusions:
- Mesp2 and Ps1 differentially regulate Dll1 expression through distinct Notch-signalling pathways.
- This differential regulation is key to establishing rostro-caudal polarity within somites.