Wnt signaling plays a vital role in many developmental processes. Wnt signaling has been implicated in neural crest induction and cell differentiation among other functions. In mice Wnts comprise a family of nineteen glycoproteins that bind to Frizzled (Fzd) receptors and LRP5/6 co-receptors. This activates beta-catenin, which translocates into the nucleus and acts as a transcription factor, resulting in differential gene expression. Specifically, Fzd 3 enhances Wnt 1 signaling. Wnt 1 and Fzd 3 are involved in neural crest induction and in neural crest-derived melanocyte development. We analyzed the expression pattern ofFzd 3 and the LRP 5/6 by in situ hybridization inmouse embryos. Our data suggests a role for these genes in neural crest induction and in melanocyte differentiation in the murine system. Results show Fzd 3 expression in the anterior part of the neural tube and in the hindbrain, while LRP 5 is expressed in the anterior part of the neural tube, in the hindbrain, and in the eye. We conclude that Fzd 3 and LRP 5 are expressed in the neural crest. In addition, Fzd 3 might act as the receptor while LRP 5 might act as the co-receptor for Wntl signaling in the murine system.
