The role of Irf6 in tooth epithelial invagination

Thickening and the subsequent invagination of the epithelium are an important initial step in ectodermal organ development. Ikk{alpha} has been shown to play a critical role in controlling epithelial growth, since Ikk{alpha} mutant mice show protrusions (evaginations) of incisor tooth, whisker and hair follicle epithelium rather than invagination. We show here that mutation of the Interferon regulatory factor (Irf) family, Irf6 also results in evagination of incisor epithelium. In common with Ikk{alpha} mutants, Irf6 mutant evagination occurs in a NF-{kappa}B-independent manner and shows the same molecular changes as those in Ikk{alpha} mutants. Irf6 thus also plays a critical role in regulating epithelial invagination. In addition, we also found that canonical Wnt signaling is upregulated in evaginated incisor epithelium of both Ikk{alpha} and Irf6 mutant embryos.