A Mouse Model for Conditional Expression of Activated Beta-Catenin in Epidermal Keratinocytes

The study develops a K5: CAT bigenic mouse model to conditionally express activated β-catenin in epidermal keratinocytes using the TET-ON system. Short-term doxycycline treatment during the telogen phase enlarges pilosebaceous units, mimicking the anagen phase, while prolonged treatment thickens the epidermis and increases keratinocyte proliferation, particularly in the basal cell layer and hair follicle's outer root sheath, leading to decreased hair density. These changes are reversible upon doxycycline withdrawal, highlighting the dependency on β-catenin signaling. This model is valuable for studying β-catenin's role in epidermal morphogenesis, hair follicle cycling, and hair growth disorders, such as alopecia.