Fig 2. Endogenous CD133 expression in postnatal murine hair follicles and lineage tracing using ZsGreen1 reporter mice.

(A-F) Frozen sections of back skin biopsies of normal C57BL/6 mice at each indicated age were immunostained with an anti-CD133 antibody. CD133 was expressed in a subpopulation of cells in the DP (circled by white dashed line) of P28 to P38 anagen hair follicles (A-E) but not in hair follicles that in catagen or later (F). (G-L) Lineage tracing of CD133+ DP cells using CD133-CreER^T2; ZsGreen1 reporter mice. The DP is co-stained for the expression of alkaline phosphatase (red), which is a specific DP marker. GFP+ cells were first detected in DPs at P28 (G) and present throughout the entire anagen (H-K). An average of 20% of telogen hair follicles contained a small population of GFP+ cells in the DP (L). (M-R) Images of ZsGreen1 expression (green) in CD133+ DP cells during the hair cycle without staining for alkaline phosphatase expression. Green fluorescent DP cells were indicated with red arrows. For every indicated mouse age, at least three mice were analyzed. Scale bar: (A-F), 100 μm; (G-R), 200 μm