Reugels, Alexander

Proper spatial and temporal specification of cells during development is crucial for the generation of cellular diversity in the nervous system of complex organisms. We are interested in the mechanisms underlying the establishment of cellular polarity and the generation of neuronal cell lineages during neurulation in Danio rerio. We were able to show that neurulation in zebrafish embryos is characterised by oriented cell divisions and the progressive establishment of cellular polarity. Mitoses in the neural plate and neural tube are planar, but in the neural keel/rod stage the mitotic spindle rotates by 90°, causing cell divisions to occur perpendicular to the plane of the neuroepithelium. However, the mechanisms and molecules that establish cellular polarity and cause the stereotypic orientation of the mitotic spindle during neurulation are still largely unknown. In order to address this topic, we are currently analyzing the putative cell fate determinant Numb and the role of the Par-3/Par-6/aPKC complex in setting up apicobasal polarity and specifying the orientation of the mitotic spindle. A major aspect of our work is the in vivo time-lapse imaging of GFP-tagged fusion proteins via confocal laser scanning microscopy.