Lineage Tracing of Hair Follicle Stem Cells in Epidermal Whole Mounts

The document from 2013 details a method for tracking hair follicle stem cells (HFSCs) in mice using the Cre/lox recombination system, specifically by expressing Cre recombinase under the control of keratin15 (K15) regulatory sequences and using tamoxifen for temporal control. This technique allows for the observation of HFSCs and their progeny in three dimensions during tissue maintenance and regeneration. The study demonstrated the multipotency of HFSCs in regenerating the pilosebaceous unit by using K15CreER(G)T2/R26RLacZ mice and detecting fully regenerated LacZ positive hair follicles up to 180 days after Cre activation. The document also provides detailed protocols for preparing and analyzing epidermal whole mounts, including tissue separation, fixation, staining, and immunofluorescent techniques, as well as the importance of controls and statistical analysis in evaluating the results.