Expression analysis of chick Wnt and frizzled genes and selected inhibitors in early chick patterning.

Wnt signaling is an important component in patterning the early embryo and specifically the neural plate. Studies in Xenopus, mouse, and zebrafish have shown that signaling by members of the Wnt family of secreted signaling factors, their Frizzled receptors and several inhibitors (sFRP1, sFRP2, sFRP3/Frzb1, Crescent/Frzb2, Dkk1, and Cerberus) are involved. However, very little is known about the expression of genes in the Wnt signaling pathway during early anterior neural patterning in chick. We have performed an expression analysis at neural plate stages of several Wnts, Frizzled genes, and Wnt signaling pathway inhibitors using in situ hybridization. The gene expression patterns of these markers are extremely dynamic. We have identified two candidate molecules for anterior patterning of the neural plate, Wnt1 and Wnt8b, which are expressed in the rostral ectoderm at these stages. Further functional studies on the roles of these markers are underway.