Figure 2.

A survey of spatial gene expression during the outgrowth and fusion of the palate. (A) Regional differences in expression domains, particularly with respect to the anterior-posterior and medial-lateral axes, highlight domains of expression in the developing palate. (B) Gene expression domains in the developing palate are organized relative to the developing rugae. In addition to SHH, multiple components of a network of signaling genes and transcription factors that are critical for palate development, including the FGF, NOTCH, and BMP pathways, exhibit restricted expression to either rugae or inter-rugae expression domains. The distribution of rugae signaling centers, generated during anterior growth, provide a mechanism to integrate A-P differences in gene expression with localized sources of patterning information. (C) Sagittal section in situ showing Shh expression restricted to the thickened epithelium of established rugae as well as the anterior edge of the RGZ epithelium prior to epithelial thickening. (D) Epithelial expression of the dual BMP/WNT antagonist Sostdc1 is restricted to the RGZ epithelium and inter-rugae domains but is downregulated at the site of rugae formation (arrowheads in C and D).