BMP signaling pathway is a negative regulator of filaggrin expression. a, b A BMP2-soaked bead (B) was able to inhibit profilaggrin/filaggrin expression (arrow) in the epidermis of a skin explant from an E18.5 embryo (b), as compared with the BSA-soaked bead (B) control (a). Dashed lines mark the boundary of the basal layer in a, b. c, d A skin sample from a P0 K14-Cre/Nog transgenic mouse showed profilaggrin/filaggrin expression was enhanced and expanded in the epidermis (d), as compared with the age-matched wild-type (Wt) control (c). Double dashed lines inicate the position of the basal layer. Bars 100 µm (a, b), 50 µm (c, d)