Morphogenesis and Maintenance of the 3D Thymic Medulla and Prevention of Nude Skin Phenotype Require FoxN1 in Pre- and Post-Natal K14 Epithelium

The study demonstrated that the FoxN1 gene was crucial for the morphogenesis and maintenance of the 3D thymic medulla and the prevention of a nude skin phenotype. Using a loxP-floxed-FoxN1 mouse model, researchers found that specific deletion of FoxN1 in keratin-14 (K14) promoter-driven thymic epithelial cells (TECs) led to the formation of 2D epithelial cysts and a loss of 3D thymic structure, which increased with age. This deletion also caused a complete hair follicle defect, resulting in a nude skin phenotype. These changes required FoxN1 deletion in both prenatal and postnatal life. The findings highlighted the distinct roles of FoxN1 in the thymus and skin, emphasizing its importance in 3D thymic epithelial morphogenesis and maintenance.