Fig. 1.

Gli1⁺, Hh-responding stem cells maintain the touch dome in mouse skin. (A and A′) X-Gal whole-mount and section staining in skin from the back of a P59 adult Gli1^LacZ/+ mouse. Arrowheads indicate touch domes. (B) β-Galactosidase (β-gal) and K8 staining in skin from the back of an adult Gli1^LacZ/+ mouse. (C) X-Gal (false-colored red) with K17 staining in skin from the back of an adult Gli1^LacZ/+ mouse. (D) K8 and GFP staining in skin from a Gli1-GIFM (Gli1^CreER/+;R26^YFP/+) mouse 9 d after tamoxifen induction at P23. Asterisks in B and D indicate nonspecific staining. Yellow arrows in D and E indicate labeled Merkel cells. The red arrows in D indicate unlabeled Merkel cells. (E) K8, K17, and GFP staining in skin from an adult Gli1-GIFM (Gli1^CreER/+;R26^YFP/+) mouse 3 mo after depilation and tamoxifen induction. (F and F′) X-Gal whole-mount and section staining in skin from the back of a Gli1-GIFM (Gli1^CreER/+;R26^LacZ/+) mouse 4.5 mo after tamoxifen induction. (G) X-Gal whole-mount staining in skin from adult control and K5-tTA;TRE-cre;Smo^flox/flox;Gli1^LacZ/+ mice 7 wk after dox withdrawal. (Scale bars, 50 μm for sections; 0.5 mm for whole-mount skin.)