Decreased cell proliferation and increased apoptosis in Chx10Cre-RBPf/fretinae. (A-D) BrdU labeling shows reduced cell proliferation in Chx10Cre-RBPf/fretina at E13.5 (D), but not at E12.5 (B), relative to wild-type controls (A, C). (E, F) TUNEL staining reveals increased cell death in Chx10Cre-RBPf/fretina at E14.5 (F) compared to wild-type controls (E). (G, H) X-gal+ mutant cells in Chx10Cre-RBPf/fretinae predominated and were distributed throughout the retina, albeit less uniformly (H), compared to that in Chx10Cre retinae (G). (I, J) Significant difference of percentages of BrdU+ cells in the total retinal cells is observed between the two genotypes at E13.5 (I, 25.3 ± 6.3% of the total retinal cells in wild-type, 13.6 ± 4.9% of the total retinal cells in Chx10Cre-RBPf/f; P < 0.05), and significant difference of TUNEL+ cells is found at E14.5 (J, 0.59 ± 0.13% of the total retinal cells in wild-type, 1.15 ± 0.14% of the total retinal cells in Chx10Cre-RBPf/f; P < 0.05). Scale bars, 100 μm.