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Wnt3a plays a major role in the segmentation clock controlling somitogenesis
Alexander Aulehla1, Christian Wehrle, Beate Brand-Saberi
1Abteilung Entwicklungsbiologie, Max-Planck-Institut für Immunbiologie, Stübeweg 51, D-79108, Freiburg, Germany.
Developmental Cell
|March 15, 2003
Summary
Wnt/beta-catenin signaling establishes the segmentation clock, crucial for vertebrate development. This pathway, via Axin2 oscillation, controls somitogenesis even when Notch signaling is disrupted.
Area of Science:
- Developmental biology
- Molecular biology
- Genetics
Background:
- Vertebral column development relies on somite formation from presomitic mesoderm (PSM).
- Somitogenesis is regulated by a molecular oscillator, the segmentation clock, which controls periodic Notch signaling within the PSM.
Purpose of the Study:
- To investigate the link between Wnt/beta-catenin signaling and the segmentation clock during somitogenesis.
- To elucidate the role of Wnt signaling in regulating the oscillatory dynamics of the segmentation clock.
Main Methods:
- Analysis of Axin2 expression patterns in the PSM.
- Investigation of Wnt3a's requirement for Notch signaling oscillations.
- Utilizing genetic manipulation to assess the impact of Wnt pathway modulation on somitogenesis.
Main Results:
- Axin2, a Wnt/beta-catenin target, exhibits oscillating expression in the PSM, independent of Notch signaling.
- Axin2 expression alternates with Lfng expression, suggesting coordinated regulation.
- Wnt3a is essential for maintaining the oscillating activity of Notch signaling in the PSM.
Conclusions:
- Wnt/beta-catenin signaling, through a negative feedback loop involving Axin2, is proposed to establish the segmentation clock.
- Wnt3a plays a critical role in controlling the segmentation clock and thus vertebrate somitogenesis.