Fig. 7. Severe disorganisation and fragility of outer and inner root sheath cells in 3-integrin-deficient hair follicles. Electron micrographs of WT (A,C,E) and 3-integrin deficient (B,D,F,G) hair follicles. (A,B) Distal area of hair follicle ORS, where hemidesmosomes are present. In 3-integrin-deficient samples (B) the ORS cells are ruffled, extending finger-like projections, and appear to be retracting from the lamina densa compared with WT controls (A). (C,D) ORS of proximal hair follicle, where hemidesmosomes are not present. In 3-integrin-deficient samples multiple layers of lamina densa were produced (D) in contrast to a single layer of lamina densa in WT controls (C). An abnormally dense accumulation of dermal fibroblasts was also evident in 3-integrin-deficient samples (D,F). (E,F) Low power micrographs of the hair follicle ORS and IRS. Note the loss of organisation of the 3-integrin-deficient ORS, with increased cellular fragility and loss of cell-cell junctions in the inner and outer layers. (G) High-power micrograph of 3-integrin-deficient inner and outer root sheath showing disruption of cell-cell contact. Four skin grafts per genotype were analysed. ORS, outer root sheath; IRS, inner root sheath; HD, hemidesmosomes; LD, lamina densa; P, cell processes or projections, DF, dermal fibroblasts. Bracket and MLLD, multi-layered lamina densa. Asterisk, cellular space. Bar represents 5 µm in A and B, 2 µm in C, 1 µm in D, E, F and G.