Fig. 3. Proliferation defects in epidermal Rb-deficient mice. (A-D) Representative sections showing BrdU incorporation in the epidermis of Rb^F19/F19 (A), Rb^F19/F19;K14cre (B), Rb^F19/F19;p107^+/–;K14cre (C) and Rb^F19/F19;p107^–/–;K14cre (D). (E-E') Quantitative analysis of the percentage of BrdU-positive nuclei per mm of epidermis in the basal layer (E) and number of BrdU-positive nuclei per mm in suprabasal layer (E') of mice with the indicated genotypes. Three 10-day-old mice of each genotype were analyzed, scoring 2-4 sections in each (mean±s.d.). (F-I) Representative sections showing BrdU incorporation in hair follicles of 10 days old mice of each genotype. (J-M) Apoptosis detection (TUNEL) in hair follicles of 10-day-old mice of each genotype. Scale bars: 100 µm. (N,N') Label-retaining population at 30 (N) and 75 (N') days after BrdU labeling in mice of the quoted genotypes. Data in N and N' come from the study of five different mice analyzing 2-4 independent sections from each animal (mean±s.d.).