Fig. 2. Expression of Msx1, Bmp2, Bmp4 and Shh in the developing palatal shelves. (A-C) Msx1 transcripts were detected in the mesenchyme of the anterior region of developing palatal shelf at E12.5 (A) and E13.5 (B), but was not detected in the posterior region of palatal shelf (C). Strong Msx1 expression was seen in the maxillary molar dental mesenchyme (dm) (C). (D-F) Bmp4 expression was found in the palatal epithelium (arrow) and mesenchyme (arrowheads) at E12.5 (D), and was restricted to the mesenchyme (arrow) at E13.5 (E). Bmp4 expression was absent in the posterior region of E13.5 palatal shelf (F). (G-I) Bmp2 expression was detected in both the epithelium and mesenchyme of the anterior region of developing palatal shelves at E12.5 (G) and E13.5 (H), but was absent in the posterior palate (I). (J,K) Shh expression was detected in the MEE (arrows) of the anterior palatal shelves at E12.5 (J) and E13.5 (K), but was not detected in the MEE of the E13.5 posterior palatal shelf (L), where Shh expression in the rugae was seen (arrows). Scale bar, 100 µm.