FIGURE 2

Epidermal stem cells in the absence of HF niches. (a) Colony-forming potential of P100 Edaradd ^cr/cr and Edaradd ^cr/+ tail epidermis. (b–e) BrdU LRCs are found in the bulge region of HFs in P100 dorsal trunk skin (b and c, bracket) of mutant and control mice. HFs of control tail contain LRCs (d, bracket), and isolated LRCs (arrowheads) are found in the basal layer of the epidermis in both control (d) and mutant (e) tail skin. Bar=50 m. (f) Dct::lacZ-positive cells of the melanocyte lineage (arrow) are distinct from the LRCs detected in the basal IFE (arrowhead). (g) Quantification of IFE LRCs/mm² of Edaradd ^cr/cr and Edaradd ^cr/+c tail epidermis (P>0.2). Error bars show SEM. (h–o) Whole-mount immunodetection of stem cell and HF bulge markers in P35 tail epidermis. Edaradd ^cr/cr epidermis broadly expresses integrin 6, but does not express the stem cell markers K15, Tenascin-C, or CD34 (i, k, m, o). In mutant skin at the point of tail attachment to the trunk (k, dotted line), secondary HFs exhibit K15 expression in a pattern identical to that seen in control tail follicles (j). Bar=100 m. SH=scale hinge.