Fig. 6. Cell proliferation in the periocular mesenchyme is not altered upon ablation of RALDH1 and RALDH3, or of RARß and RAR. (A-C) Distribution of proliferating cells (assessed by Ki-67 expression) in E11.5 wild-type (A), Aldh1a1/3-null (B) and Rarb/g^{NCC–/– lacZ} (C) fetuses. The histological sections illustrated have been selected to provide the best match between mutant and wild-type embryos. d, dorsal retina; le, lens; m, periocular mesenchyme; o, optic nerve; v, ventral retina. Scale bar: 50 µm.