Fig. 4. Reduced proliferation in adult 3-integrin-deficient skin grafts. Longitudinal sections through WT (A,C) and 3-integrin-deficient (B,D,E) adult skin grafts were examined for proliferation by immunohistochemistry with an anti-Ki67 antibody. Keratinocyte proliferation in interfollicular epidermis (A,B) was normal in the 3-integrin-deficient skin grafts, but the number of Ki67-positive cells was significantly reduced in 3-integrin-deficient hair follicles (D) compared with WT controls (C). Clusters of 3-integrin-deficient hair follicles (E) had very small numbers of Ki67-positive cells. (F) Quantification of the percentage of keratinocytes that are Ki67 positive±s.e.m.; eight skin grafts for each genotype were analysed and the experiment was repeated three times. Over 320 follicles per genotype were analysed.; P*<0.0005. Arrows, examples of Ki67-positive nuclei. Arrowheads, base of mutant hair follicles with less Ki67-positive nuclei. Bar represents 50 µm in A, B and E; 100 µm in C and D.