Exploiting the Keratin 17 Gene Promoter To Visualize Live Cells in Epithelial Appendages of Mice

The study demonstrated that a 2-kilobase segment of the mouse keratin 17 gene promoter could drive the expression of green fluorescent protein (GFP) in major epithelial appendages of transgenic mice, such as hair, nails, glands, and oral papilla. This GFP expression allowed researchers to visualize growth cycle-related changes in hair follicles and the effects of the hairless mutation in live skin tissue. The study also found that deleting a 48-base pair interval containing a Gli-responsive element from the promoter led to a loss of GFP fluorescence in most appendages, indicating that sonic hedgehog signaling was involved in K17 regulation. This compact promoter was proposed as a novel tool for targeted gene expression and manipulation in epithelial appendages of transgenic mice.