Fig. 2. Notch1 loss causes decreased mitotic rates and a slight increase in apoptosis, but not acceleration in catagen onset. (A) Hematoxylin and Eosin staining of anagen-deleted Notch1 (anN1), embryo-deleted Notch1 (emN1) and wild-type (WT) skin at 9 days (P9), P13, P17 and P22 old. Note that hair cycling was not altered in Notch1-deficient hair follicles. (B) TUNEL staining of emN1 and anN1 follicles (P9), and of wild-type hair follicles [P9 and P16 (catagen)]. (C) Average number of TUNEL-positive cells per hair follicle in each genotype shown in B. ^*P<0.05 for both wild type versus emN1 and anN1 versus emN1; ^**P<0.05 for both wild type versus wild type (catagen) and anN1 versus wild type (catagen); ^***P<0.005. (D) Immunofluorescence staining of BrdU (green) and Ki67 (red). (E) Progenitor labeling index of anN1, emN1 and wild-type hair follicles and epidermis. ^*P<0.01 for anN1 versus emN1 and wild type versus emN1. Error bars represent s.d. Scale bars: 200 µm in A; 20 µm in D.