Fig. 3. HB-EGF is not required for cell proliferation in eyelid closure. (A,B) BrdU incorporation in eyelids of HB^del/+ (A) and HB^del/del (B) embryos at E15.5. (C,D) High magnification of A and B, focusing on the leading edge. BrdU-positive cells (brown nuclei) are mostly in the dermis but not in the epidermis. Scale bars: 100 µm for A and B; 50 µm for C and D. (E) Scoring of BrdU-positive cells based on the data shown in A and B. Data represent the mean value±s.e.m. of the results obtained in three individual embryos. N.S, not significant.