Notch1 expression pattern during embryonic eyelid closure and genetic overexpression of N1-ICD in POMC. (A–C) Immunoflurescence staining with anti-Notch1 antibody on sections of mouse eyelids at E13.5~E17.5. Note that Notch1-positive signals (red) are detected predominantly in eyelid epidermis, with very few in the dermis. Nuclear counter staining with DAPI is shown in blue. (D) Schematic representation of N1-ICD expression via Cre-loxP system in POMC. The rtTA is constitutively expressed in Kera-positive POMCs. In the presence of Dox, Cre recombinase is induced to delete the Neo/Stop cassette, permitting transcription of Notch1 ICD. Co, cornea; Le, lens; LL, lower lid; Re, retina; UL, upper lid.