Figure 6.
Abnormal differentiation of the inner root sheath in Cutl1Z/Z whisker follicles. (A) Expression of the CDP protein in the wild-type whisker follicle. A longitudinal section through the whisker follicle of a 5-day-old mouse was stained with the anti-CDP antibody C3HD and counterstained with hematoxylin. (B,C) Higher magnification of the areas indicated in A. Brown staining identifies nuclear expression of CDP in the inner root sheath (IRS) including the companion cell layer (CCL). (D) Schematic diagram of hair follicle differentiation. Multipotent stem cells migrate from the bulge through the outer root sheath (ORS) to the hair bulb, where they become committed to the different cell lineages of the IRS and hair shaft (HS). Gray shading denotes CDP expression in the different cell layers. (E,F) Histological sections of wild-type (E) and Cutl1 mutant (F) whisker follicles at birth. The boxed areas are shown above at higher magnification. Mitotic cells are indicated by arrowheads. (Co) Cortex; (DP) dermal papilla; (Cu) cuticle layer of the IRS; (HCu) cuticle layer of the hair; (He) Henlé's layer; (Hu) Huxley's layer; (Ma) matrix; (Me) medulla.