Induktion des Telencephalons in der Zebrafisch Entwicklung
Final Report Abstract
Forebrain development starts from a simple sheet of ectodermal epithelial cells at the anterior neural plate and ends in one of the most complex cellular structures known. It has been shown that one major requirement during an early step of this transformation is the depletion of Wnt signalling within the anterior neural plate. However, the molecular events driving the differential regionalisation of this area into eye field (medial) and telencephalon (marginal) fates are still unknown. One major finding of this project is that the BMP pathway is active in the anterior neural ectoderm from late blastula to early gastrula stage in zebrafish. Bmp2b mutants and mosaic loss of function experiments reveal that BMP acts as a repressor of eye field fate through inhibition of its key transcription factor Rx3, thereby protecting the future telencephalon from acquiring eye identity. This BMP driven mechanism initiates the establishment of the telencephalon prior to the involvement of Wnt antagonists from the anterior neural border (ANB). Furthermore, we demonstrate that Rx3 and BMP are respectively required to maintain, and restrict the chemokine receptor cxcr4a to the eye field. Analysis of the cxcr4a mutant revealed that chemokine signalling is contributing to the morphogenetic separation of eye field and telencephalic cells during early neurulation. Future projects will aim to elucidate the precise role of Cxcr4a during eye field/telencephalon boundary formation.
Publications
- (2012). BMP Signaling Protects Telencephalic Fate by Repressing Eye Identity and Its Cxcr4-Dependent Morphogenesis. Dev Cell 23, 812-22
Bielen, H. and Houart, C.
