Fig. 2. Sox10 expression during melanocyte development. Skin sections obtained from (A) an E16.5 embryo, (B) an E18.5 embryo and (C) a P2 mouse (Dct-lacZ) were stained with anti-Sox10 (green) and anti-ß-gal (red). Sox10 expression was detected in all ß-gal⁺ melanoblasts in the epidermis (A) and in the developing hair follicle (B). Downregulation of Sox10 was observed in some melanocytes located in the bulge area (C). Arrowheads indicate ß-gal⁺ melanoblasts. Scale bars: 50 µm. (D) Frequency of Sox10⁺ melanocytes located in various regions of developing skin, shown as percentages of Sox10⁺ cells in ß-gal⁺ melanoblasts located in the epidermis of the E18.5 embryo, or the bulge/sub-bulge region or hair matrix region of the P2 or P4 mice. (E,F) Downregulation of Sox10 mRNA in bulge melanocytes. Expression of Sox10 mRNA was examined by in situ hybridization/immunohistochemistry double staining. (E) ß-gal⁺ (red) melanoblasts in a developing P2 hair follicle. All melanoblasts expressed Sox10 mRNA (green). (F) Melanocytes in a P4 hair follicle. Some Sox10-negative melanocytes were observed in the bulge region. Scale bars: 50 µm.