Fig. 1. Expression pattern of Mn1 mRNA in developing mouse embryos. mRNA signals were detected by whole-mount in situ hybridization (A-C) or section in situ hybridization (D-F). (A) Mn1 mRNA expression was first detected in the developing brain tissues and in the craniofacial mesenchyme at E9.5. (B-E) Strong Mn1 mRNA expression was observed in the developing brain, frontonasal processes, maxillary processes, mandibular processes, the second branchial arch, the developing somites and limb buds at E10.5 (B,D) and E11.5 (C,E). (F) Section in situ hybridization showing strong Mn1 mRNA expression in the developing palatal mesenchyme and in the preossification mesenchymal cells in the mandible. ba1, first branchial arch; ba2, second branchial arch; e, eye; fb, forebrain; fl, forelimb; fnp, frontonasal process; hb, hindbrain; hl, hindlimb; man, mandibular process; max, maxillary process; mb, midbrain; ov, otic vesicle; p, palatal shelf; so, somite; t, tongue. Arrowheads in E indicate the initial palatal outgrowths.