Fig. 5. Altered IGF/IGFBP equilibrium in the hair matrix of Notch1-deficient hair follicles. (A) Quantitative reverse transcriptase (qRT)-PCR of IGF signaling components. Error bars represent s.e.m. (B) Immunohistochemistry (Igfbp2 and Igfbp3) and in situ hybridization (Igf1R and insets for Igfbp3) of IGF signaling components on hair follicles. DAPI was used to label nuclei during antibody staining. Arrows indicate dermal papilla (DP)-specific Igfbp3 immunoreactivity. Note the mRNA and protein expression of Igfbp3 in the DP, in which Notch1 is not expressed. (C) Histological comparisons of the hair follicles from the genotypes specified. Note that the matrix size is restored in embryo-deleted Notch1 (em-N1);Ivl::Igf1 follicles. (D) Average number of hair matrix cells (below the red line in C) per hair follicle. Error bars represent s.d. anN1, anagen-deleted Notch1. Scale bars: 40 µm in B; 200 µm [skin hematoxylin and Eosin (H&E) staining] and 50 µm (follicular H&E and DAPI staining) in C.