Fig. 4. Embryonic and newborn hair follicle, mammary and tooth phenotypes of mice carrying epidermal-specific deletions of Bmpr1a. (A,B) Histology of E16.5 dorsal skin from K14-Cre43; Bmpr1a^cl/+ control (A) and K14-Cre43; Bmpr1a^cl/cl (B) embryos. (C,D) Anti-K17 immunofluorescence (red) of skin sections from the embryos shown in A and B, respectively. (E,F) Mid-dorsal skin from K14-Cre43; Bmpr1a^cl/+ control (E) and K14-Cre43; Bmpr1a^cl/cl (F) newborns. (G-I) Mid-ventral skin from bcre-32; Bmpr1a^cl/+ control (G), bcre-32; Bmpr1a^cl/null (H) and bcre-32; Bmpr1a^cl/null; Bmpr1b^null/null (I) newborns. (J,K) Sagittally sectioned mammary buds from E13.5 K14-Cre43; Bmpr1a^cl/+ control (J) and K14-Cre43; Bmpr1a^cl/cl (K) embryos. (L,M) Whole-mount in situ hybridization of E13.5 K14-Cre43; Bmpr1a^cl/+ control (L) and K14-Cre43; Bmpr1a^cl/cl (M) embryos with a Wnt10b probe. Mammary buds are indicated (arrows). (N,O) Sagittally sectioned inguinal mammary gland (arrows) from newborn K14-Cre43; Bmpr1a^cl/+ control (N) and K14-Cre43; Bmpr1a^cl/cl (O) mice. (P,Q) Transverse sections of oral cavity from E13.5 K14-Cre43; Bmpr1a^cl/+ control (P) and K14-Cre43; Bmpr1a^cl/cl (Q) embryos showing molar tooth buds. (R,S) Sagittally sectioned E16.5 K14-Cre43; Bmpr1a^cl/+ control (R) and K14-Cre43; Bmpr1a^cl/cl (S) heads showing absence of developing incisor teeth in the mutant (red arrows). (T,U) Sagittally sectioned K14-Cre43; Bmpr1a^cl/+ control (T) and K14-Cre43; Bmpr1a^cl/cl (U) newborn heads. Incisor teeth (red arrows) and molars (green arrows) are indicated in T and are absent at the corresponding locations in U. Vibrissa follicles (blue arrows) are present in the mutant.