Fig. 3. Immunolocalization of Int4 (A,B), BPAG1 (C,D), K5 (E,F) and K6 (G-I) in skin sections from 1-day-old Plec^flox/flox (control) and K5-Cre KO mice. (A,B) In control epidermis, the Int4 signal was confined to the basal membrane (arrowheads) of basal keratinocytes and the outer root sheath of hair follicles, whereas in K5-Cre KO epidermis, it was slightly reduced and less polarized. In blistered areas (inset in B, asterisk), Int4 was located at blister floors. (C,D) Note more discontinuous BPAG1 staining along basal keratinocyte membranes (arrowheads) in K5-Cre KO compared to control epidermis. Inset in D shows BPAG1 localization at the floor (arrowheads) of blisters (asterisk). (E,F) The K5 signal was restricted to basal keratinocytes and rare transit amplifying cells (arrow), without noticable differences between control and K5-Cre KO epidermis. In blistered areas (inset in F, asterisks), K5 was located at blister roofs (arrowheads denote the blister floor). (G-I) In control skin, K6 was exclusively expressed in hair follicles (G), while in leg skins of K5-Cre KO mice, in addition to hair follicles (H), patches of suprabasal keratinocytes above microblisters were K6-positive (I). In I the dashed line indicates the dermo-epidermal border and the dotted line, a microblister separating the epidermis from the underlying dermis. Asterisks, blister. Bar, 20 µm.