Fig. 1. The epidermis of adult K10^-/- mice showed hyperkeratosis and acanthosis; cells and nuclei were enlarged (B). Keratohyalin was increased (B, inset, arrow) compared with that in the wild-type (A). A and B show H&E-stained paraffin sections of ear skin. DAPI staining of normal ear epidermis showed epidermal proliferative units (C, epidermal sheet, small arrow; E, higher magnification, arrow; G, section, arrow; large arrow in C and D, hair follicle), which were absent in knockout mice (D, epidermal sheet; F, higher magnification of D; H, section). In normal epidermis Ki-67 was restricted to basal cells (I), whereas it was expressed throughout the basal layer and in two to three suprabasal layers in K10^-/- mice (K). sb, stratum basale; sg, stratum granulosum; ss, stratum spinosum. Bars, 40 µm. The respective wild-type and knockout photos are of the same magnification.