Fig. 2. Utricle formation in Hr^-/- mice. (A) Histology of backskin from Hr^-/- mice. Hematoxylin-Eosin staining of sagittal sections from backskin at the indicated ages and genotypes. Arrowheads indicate morphological change in the infundibulum of Hr^-/- skin. (B) Expression of keratin markers in utricles. Immunohistochemical detection of keratin markers in consecutive serial sections of backskin from P19 Hr^-/- (top panels; -/-) and wild-type (+/+) mice (bottom panels). H&E, Hematoxylin-Eosin; K10, keratin 10; K14, keratin 14; K17, keratin 17. Arrowheads indicate positive signal in utricle; arrows indicate epithelial remnants; thick arrows indicate sebaceous glands. (C) Utricles (arrowheads) do not express hair markers. Immunohistochemical detection of Trichohyalin, a hair marker, in P15 Hr^-/- backskin. (D) Immunofluorescent detection of K10 (red) and K17 (green) in sagittal skin sections from P19 Hr^-/- and wild-type mice. Brackets indicate expansion of K10-positive region. Scale bars: 50 µm.