Fig. 2.
Deletion of Pten in the skin results in skin, coat abnormalities, and hamartomas. (A) Skin on the abdomen of PtenloxP/loxP; MMTV-cre mice is more wrinkled (right, white arrow) than skin on Ptenwt/loxP; MMTV-cre control littermates (left) at postnatal day 7 (P7). (B) Coat of PtenloxP/loxP; MMTV-cre mice (right) is shaggy and ruffled compared with the smooth coat of Ptenwt/loxP; MMTV-cre littermate (left) at P21. (C–L) Hematoxylin and eosin staining. Epidermis of PtenloxP/loxP; MMTV-cre mice is papillary in appearance (D). Acanthosis with hyperkeratosis and hypergranulosis are apparent in Pten mutant skin (F). Skin from control mice is shown in C and E. Black arrows denote sebaceous glands, which were 61% more abundant in the dermis of Pten mutants compared with control skin by 3 wk (n = 4, P = 0.01). (G–L) Staining of paws (G and H), hair follicles (I and J), and tongue epithelium (K and L) of Ptenwt/loxP; MMTV-cre (G, I, and K) and PtenloxP/loxP; MMTV-cre (H, J, and L) animals. Epithelium of hair follicles and tongue of PtenloxP/loxP; MMTV-cre mice is several cell layers thicker (J and L) than controls (I and K). Arrowheads denote hair follicle epithelium. Acanthosis with hypergranulosis, hyperkeratosis, and parakeratosis are present within hamartomatous growths on paws of Pten mutant mice (H). Tissues are from 3-wk-old (C–F, I, and J) and 9- to 10-wk-old (G, H, K, and L) animals. (M) Average epidermal thickness in P2, 6- and 9-wk-old PtenloxP/loxP; MMTV-cre mice (black bars) was increased compared with Ptenwt/loxP; MMTV-cre mice (white bars, n = 3 for each genotype and age, P < 0.03). (Scale bar for A = 0.5 cm; B = 1 cm; C, D, G, and H = 100 μm; E and F = 10 μm; I and J = 20 μm; and K and L = 50 μm.)