Figure 6. The emergence of Dlx1^CreER- and Slc1a3^CreER-marked cells during skin development.

a, Whole-mount immunostaining of the tail skin in double-transgenic Dlx1^CreER/or Slc1a3^CreER/Rosa-tdTomato mice. Mice were injected with tamoxifen (TM) and sacrificed at the indicated ages. Dlx1^CreER- or Slc1a3^CreER-marked cells were first detected at PD3 or PD0, respectively, in the K10⁻ region. By PD9, Dlx1^CreER- or Slc1a3^CreER-marked cells were preferentially observed in interscale (K10⁺) or scale (K10^–), respectively; this pattern was maintained in adults. The dashed line represents the boundary of tail epidermis structure (circle is scale, while the remaining marked area is interscale). Asterisks indicate HFs. Scale bars, 100 μm. b, Number of tdTomato⁺ cells within each structure. Error bars show s.e.m.; **: P<0.01; *: P<0.05. Statistical analyses were performed using the two-tailed Student’s t-test when n ≥ 3; an individual bar is shown for each mouse otherwise. [Dlx1^CreER PD14, n = 4 mice, interscale (non-line) vs interscale (line), P=0.05, interscale (line) vs scale, P=0.006, interscale (line) vs scale, P=0.005; Slc1a3^CreER PD9, n = 5, interscale (non-line) vs scale, P=1×10⁻¹³, interscale (line) vs scale, P=1×10⁻¹⁸.] Experiments are repeated twice with number of mice indicated above for images in (a).