Fig. 5: Combined deficiency of Mkk4 and Mkk7 causes failure of optic nerve formation and disruption of retinal lamination.

a Brains were removed from adult WT and Mkk4/Mkk7 double-deficient mice with optic nerves intact (arrowheads). Near complete loss of both optic nerves was evident in all Mkk4/Mkk7 mutant brains examined (N = 8 per genotype). b Representative 3 μm plastic sections stained with H&E further demonstrate severe optic nerve head abnormalities (asterisk) in Mkk4/Mkk7 double-deficient mice eyes (N = 4 per genotype). c Mkk4/Mkk7 double mutants display extensive disruption of all retinal layers (N = 4 per genotype). Scale bars: 100 μm