Fig. 4

SHH signaling was overactivated in the GAG-deficient incisors. A–D Whole mount in situ hybridization of E12.0 mouse embryos showed an expanded territory of Shh (white arrows) in both upper and lower incisor areas of the K14^Cre/+;Fam20B^fl/fl mice compared with the controls (Fam20B^fl/fl). Note that Shh signal in hair follicles can be used as internal references for the comparison between knockout and control mice. E, F ISH of Shh on the coronal sections of lower incisors showed an expanded expression of Shh in the GAG-deficient dental epithelium toward the mesial side (white arrow) compared with controls. G–J HH downstream markers, Gli1 and Patched1, showed broader reactivity in the dental mesenchyme of K14^Cre/+;Fam20B^fl/fl mice, as indicated by Gli1- and Ptched1-LacZ indicators (dashed lines plotted). Scale bars: 500 μm in A and B; 250 μm in C, D and G–J; 50 μm in E and F