Expression of Lef1 and Wnt10b are often seen where inductive epithelial–mesenchymal interactions occur during development (e.g., hair follicles,papillae, teeth, mammary glands, and lung)
Up-regulation of the Wnt/β-catenin signaling by LiCl increased the number of fungiform papillae and their expression of Shh while addition of Shh suppressed Wnt/β-catenin signaling during fungiform papillae development in experiments using tongue cultures. These results indicate that interactions between Wnt and Shh signaling pathways play a role in fungiform papilla development.
THIS IS THE LINK: http://www.pnas.org/content/104/7/2253.full