Fig. 8. Altered expression of Bmp4 in Msx1/2 mutant embryos. (A,B) Wnt1 expression was maintained in hindbrain, dorsal neural tube, and isthmus in Msx1/2 double-mutant embryos. (C-F) Unchanged expression of Fgf8 in the median nasal prominence (mn), isthmus (is) and pharyngeal arch1 in Msx1/2 mutant (D,F) compared with control (C,E) embryos. Also note that expression of Fgf8 (F) and Tbx1 (H) in the peripharyngeal region was not significantly affected in the mutant (arrows). (I-N) Bmp4 was upregulated in the forebrain, cranial mesenchyme, body wall epithelium (arrows), maxillary prominence, distal first pharyngeal arch, and proximal second pharyngeal arch (arrowhead). (K-N) Section analysis of Bmp4 whole-mount embryos. Enlarged views of boxes in K and L are shown in M and N. The cranial mesenchyme and migratory neural crest (arrow in N) express Bmp4 highly in Msx1/2 mutants. Scale bars: in B (for A,B), D (for C,D), F (for E,F), H (for G,H), J (for I,J), 0.2 mm.