Shh governs segmentation of tooth germs by modulating Wnt-and-BMP pathways

Shh is involved in pattern formation of many ectodermal organs such as tooth, limb, hair, mammary gland, and feather by controlling proliferation and differentiation of cells. It has been reported that Shh, Smo, Sostdc1 or Lrp4 deficient mice showed the abnormal tooth patterns such as molar fusion or supernumerary teeth. In this study, by blocking Shh activity in WT mouse embryos using 5E1, an antibody against SHH protein, we found that Shh controlled the segmentation of teeth by regulating the expression of Sostdc1, which had been known as the negative regulator in the Bmp and Wnts pathway. We propose that Shh governs the tooth segmentation by modulating Wnt and Bmp signaling pathways.