The skin epidermis is a highly compartmentalized tissue consisting of a cornifying epithelium called the interfollicular epidermis (IFE) and associated hair follicles (HFs). Several stem cell populations have been described that mark specific compartments in the skin but none of them is specific to the IFE. Here, we identify Troy as a marker of IFE and HF infundibulum basal layer cells in developing and adult human and mouse epidermis. Genetic lineage-tracing experiments demonstrate that Troy-expressing basal cells contribute to long-term renewal of all layers of the cornifying epithelium. Single-cell transcriptomics and organoid assays of Troy-expressing cells, as well as their progeny, confirmed stem cell identity as well as the ability to generate differentiating daughter cells. In conclusion, we define Troy as a marker of epidermal basal cells that govern interfollicular epidermal renewal and cornification.

皮肤表皮是一种高度分隔的组织，由称为毛囊间表皮 (IFE) 的角化上皮和相关毛囊 (HF) 组成。几种干细胞群已被描述为标记皮肤中的特定区室，但它们都不是 IFE 所特有的。在这里，我们将Troy鉴定为发育中和成人及小鼠表皮中 IFE 和 HF 漏斗基底层细胞的标记。遗传谱系追踪实验表明，表达Troy的基底细胞有助于角化上皮各层的长期更新。对表达 Troy 的细胞及其后代进行的单细胞转录组学和类器官分析证实了干细胞的身份以及产生分化子细胞的能力。总之，我们将Troy定义为控制毛囊间表皮更新和角化的表皮基底细胞的标记。