Comparison of Bmp2 (A, B), Bmp4 (C, D), Msx1(E, F) and Shox2 (G, H) mRNA expression in the anterior palate of Osr2-IresCre;Smo+/c (A, C, E, G) and Osr2-IresCre;Smoc/c mutant (B, D, F, H) embryos at E13.5. Arrowheads in A-F point to differences in expression in the control and mutant palatal shelves. In comparison with the control embryos, Bmp2 mRNA was downregulated whereas Bmp4 and Msx1 mRNAs were up-regulated in the anterior palatal mesenchyme. (G,H) Shox2 mRNA expression was unaltered in the Osr2-IresCre;Smoc/c mutant palate. p, palatal shelf; t, tongue.