(A–D) Frontal sections through developing olfactory structures of an E14.5 Mef2c-F10N-Cre;R26R embryo. (A–B) X-gal staining and immunostaining for markers of mature neurons (Tuj1) and muscle (Actin). (C, D) High magnification images of olfactory bulb and nasal epithelium as outlined in red dashed insets in (A, B) with X-gal staining directly detected by 633nm fluorescence emission in combination with antibody staining of mature neurons (Tuj1). Abbreviations: NS, nasal septum; OB, olfactory bulb; OE, olfactory epithelium; ONL, olfactory nerve layer. Scale bars: 0.5 mm in A, 0.2 in B–D.