Gastrulation is a central process in early development in which a seemingly unstructured blastula rearranges to form an embryo with a distinct head-to-tail, left-to-right and bottom-up morphology. During this process, the three germ layers, ectoderm, mesoderm and endoderm, are formed and progenitor cells are brought into the positions from where they later will form more complex tissues and organs. Although substantial information into the mechanisms that establish cell fates during gastrulation has been gathered, much less has been learned about the molecular and cellular mechanisms underlying gastrulation movements.

To obtain insight into these processes, we have established an assay system that allows us to analyse the movement and morphology of single cells at early stages of zebrafish gastrulation.

With the help of this assay system, we have identified the role of two signalling pathways, the Wnt/ planar cell polarity and the PDGF/ PI3K pathways, in controlling specific aspects of cell – adhesion, dynamic cytoskeletal rearrangements and endocytosis during gastrulation. Our study on the function of these (and possibly other) pathways will help to elucidate the principles that underlie morphogenesis during vertebrate gastrulation.