Figure 3.

EGFR Controls Cell Proliferation as well as Centrosome Function and DNA Integrity

(A) Immunofluorescence staining for ITGB4 (green), EGR1 (red), and nuclei (blue) from P3 control and Egfr^Δep mice.

(B) Immunohistochemistry staining for phospho-ERK1/2 from P3 control and Egfr^Δep mice. Asterisk indicates hair pigmentation.

(C) Quantification of BrdU⁺ ORS cells of P2 mice 24h after BrdU pulsing. Bars show analysis of 10 follicles per mouse from n = 4 mice per genotype. Data are represented as mean ± SD. p values less than 0.05 were considered significant, with ***p < 0.001 as determined by Student's t test.

(D) Quantification of the number of Ki67⁺ IFE nuclei from frozen back skin sections from control and Egfr^Δep mice at indicated time points. MF, microscopic field. Bars show analysis of 6 microscopic fields per mouse from n = 3 mice per genotype. Data are represented as mean ± SD. p values less than 0.05 were considered significant, with **p < 0.01 as determined by Student's t test.

(E) Quantification of the number of BrdU⁺ cells from epidermal cell suspensions analyzed by fluorescence-activated cell sorting from control and Egfr^Δep mice at indicated time points. Bars show analysis of n = 3 mice per genotype. Data are represented as mean ± SD. p values less than 0.05 were considered significant, with **p < 0.01 as determined by Student's t test.

(F) Immunofluorescence staining for Tubulin (green), Pericentrin (red), and nuclei (blue) from primary keratinocytes derived from control and Egfr^Δep mice. Arrows point to centrosomes. Scale bars, 5 μm.

(G) Quantification of the percentage of primary keratinocytes harboring more than two centrosomes. Bars show analysis of 15 cells per mouse from n = 3 mice per genotype. Data are represented as mean ± SD. p values less than 0.05 were considered significant, with ***p < 0.001 as determined by Student's t test.

(H) Immunofluorescence staining for F-Actin (green) and nuclei (blue) of primary keratinocytes derived from P8 control and Egfr^Δep mice. Arrows highlight nuclear fragments. Scale bars, 5 μm.

(I) Immunofluorescence staining for P-Cadherin (green), activated caspase 3 (red), and nuclei (blue) from control and Egfr^Δep mice at E18.5, showing IFE (top) and HF (bottom).

(J) Immunofluorescence staining for ITGB4 (green), activated caspase 3 (red), and nuclei (blue) from control and Egfr^Δep mice at P10, showing IFE (top) and HF matrix (bottom). Arrow highlights an apopotic cell.

(K) Immunofluorescence staining for γH2AX (green) and nuclei (blue) from control and Egfr^Δep mice at P10, showing IFE (upper panel) and HF matrix (lower panel). Arrows highlight spots of DNA damage.

(L) Immunohistochemical staining of TP53 on sections of P10 control and Egfr^Δep mice, showing HF matrix. Asterisk indicates hair pigmentation, delineated area marks dermal papilla (DP).

Scale bars, 20 μm unless otherwise stated. See also Figure S3.