Fig. 5. Epidermal overexpression of lamin A and lamin Adel50 leads to aberrant expression of keratin 5 and keratin 6, and increased proliferation, as shown by immunohistochemistry with antibodies to keratin 5 (CK5), keratin 6 (CK6) and phospho-histone H3 (PHH3). (A,B,F) FVB/N wild type in late anagen stage. (C-E,G,H) Bi-transgenic animals from F1 line VF1-07 of 9 and 18 weeks. (A) CK5 normal expression pattern in the basal cells of the interfollicular epidermis, the outer root sheet and the peripheral cells of the sebaceous glands. (B) CK6 normal expression pattern in the inner root sheet. (C) In progerin-expressing mice, CK5 expression is also detected in the suprabasal population of keratinocytes and is expressed equally across the sebaceous glands. (D,E) CK6 expression is also detected in the interfollicular epidermis and sebaceous glands. (F) Normal PHH3 expression in the bulb of a late anagen hair follicle. (G,H) Increased proliferation in cells of the interfollicular epidermis and the hair follicle. Transgenic mice were supplied with doxycycline until time of weaning – day 21. Scale bars: C-E, 100 µm; A,B,F-H, 50 µm.