Figure 1: Light micrographs showing the localization of heparanase during palate formation. (a) Palatal shelf of a mouse embryo at E13.5. Heparanase signal was not evident in the palatal shelf. (b) Higher magnification of square marked in (a). Some epithelial cells and mesenchymal cells facing the palatal shelf at the bottom of the tongue had weak heparanase labeling (arrows and arrowheads). (c) Palatal shelves of a mouse at E14.5. The epithelial cells of palatal shelves had heparanase labeling. (d) Higher magnification of the square marked in (c). Intense reactivity was evident in the cytoplasm of the epithelial cells (arrowheads). Some stromal cells also had heparanase reactivity (arrows). (e) Palate of a mouse embryo at E15.5. The MES was observed in the middle of palate. Epithelial cells of palate and mesenchymal cells located at the ossification center ( ) had heparanase reactivity. (f) Higher magnification of the square marked in (e). The cells of the MES (white arrowheads), epithelial triangle (arrowheads), and epithelial island (arrow) show heparanase reactivity. (g) Palate of a mouse at P0. The palatal and maxillary bone was observed. (h) Higher magnification of the square marked in (g). Heparanase localization was evident in osteoblasts on the palatal bone surface. Strong reactivity of heparanase was evident in the basal cells of oral and nasal epithelium of the palate. Some stromal cells also had heparanase reactivity. PS, palatal shelf; P, palate; T:, tongue; MES, medial epithelial seam; PB, palatal bone; MB, maxillary bone; OB, osteoblasts; O, oropharynx; N, nasopharynx. Bars: (a, c, e, g, and h), 50 μm; (b, d, f), 25 μm.