Wnt6 marks sites of epithelial transformations in the chick embryo

In a screen for Wnt genes executing the patterning function of the vertebrate surface ectoderm, we have isolated a novel chickWnt gene, chickWnt6. This gene encodes the first pan-epidermal Wnt signalling molecule. Further sites of expression are the boundary of the early neural plate and surface ectoderm, the roof of mesencephalon, pretectum and dorsal thalamus, the differentiating heart, and the otic vesicle. The precise sites of Wnt6 expression coincide with crucial changes in tissue architecture, namely epithelial remodelling and epithelial–mesenchymal transformation (EMT). Moreover, the expression of Wnt6 is closely associated with areas of Bmp signalling.