Fig. 4. Gene expression induced by protein soaked beads in the anterior palatal mesenchyme. (A-E) BMP4-soaked beads induced the expression of Msx1 (A) and Bmp4 (C) in E12.5 wild-type palatal mesenchyme, but failed to induce Bmp4 expression in the Msx1^–/– palatal mesenchyme (D). Control BSA beads failed to induce Msx1 (B) and Bmp4 (E). (F) Shh-soaked beads failed to induce Bmp4 expression in wild-type palatal mesenchyme. (G,H) Endogenous Bmp4 expression was not affected by an anti-Shh antibody bead implanted in the palatal explant containing both the epithelium and mesenchyme (G), when compared with the BSA control (H). (I-K) Similar to the BSA-soaked control beads (K), BMP4-soaked bead failed to induce Bmp2 expression in the Msx1^–/– palatal mesenchyme (I) and wild-type palatal mesenchyme (J). (L,M) Shh-soaked beads induced Bmp2 expression in the palatal mesenchyme of both Msx1 mutant (L) and wild-type (M) palatal mesenchyme. (See Fig. 1M for indication of cuts made during dissection to isolate the regions of palatal tissue used in this figure.) b, bead.