Figure 4. Keratinocyte-specific TAK1 deletion delays hair cycle progression in adolescent mice.

(A) Schedule of tamoxifen application. The hair cycle was synchronized to anagen phase by wax depilation, and tamoxifen was topically applied to the dorsal skin of Map3k7 ^fl/flK14-Cre-ER^T2mice to delete TAK1. As controls, Map3k7 ^fl/fl mice or Map3k7 ^fl/flK14-Cre-ER^T2 mice were treated with tamoxifen or ethanol, respectively. (B) Clinical appearance at the indicated time point after the depilation. At 2 weeks, hair shaft formation was noted in the control mice, while hair shaft growth was not seen in the tamoxifen-treated Map3k7 ^fl/flK14-Cre-ER^T2 mice. (C) Histological analysis at the indicated time point after the depilation. Anagen progression was severely delayed in TAK1-deleted mice at 1–3 weeks. Scale bar, 100 µm.