Fig. 4. Analysis of gene expression in the fusing lip of Nestin cre;Bmpr1a n/f mutant embryos. (A-D) Fgf8 expression in the fusing lip region of wild-type and Nestin cre;Bmpr1a n/f at the labeled stage. (E-L) Fgf8 (E,F), p63 (G-J) and pitx1 (K,L) expression in the edge epithelium of the MNP and MP of wild-type and Nestin cre;Bmpr1a n/f mutant 10.5 dpc embryos. Arrows denote areas of hybridization that are absent in the mutant embryos. (E,F,H,J-L) Ventral views; (G,I) lateral oblique views. (M-O) Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick-end labeling (TUNEL) studies on sections from wild-type and Nestin cre;Bmpr1a n/f mutant embryos. Arrows denote the area of elevated apoptosis in the mutant embryo. Two examples of mutant embryos are shown (N,O).