Transient activation of beta -catenin signaling in cutaneous keratinocytes is sufficient to trigger the active growth phase of the hair cycle in mice.

Wnts have key roles in many developmental processes, including hair follicle growth and differentiation. Stabilization of beta-catenin is essential in the canonical Wnt signaling pathway. We developed transgenic mice expressing a regulated form of beta-catenin in the skin. Chronic activation of beta-catenin in resting (telogen) hair follicles resulted in changes consistent with induction of an exaggerated, aberrant growth phase (anagen). Transient activation of beta-catenin produced a normal anagen. Our data lend strong support to the notion that a Wnt/beta-catenin signal operating on hair follicle precursor cells serves as a crucial proximal signal for the telogen-anagen transition.