Fig. 3. Differential requirement of En genes for mouse midbrain and cerebellar development. (A) Schematic illustrating the detailed expression profile of each En allele (En1, En2 and En1^flox/Cre) within the mes/r1 region. (B-K) Cresyl Violet-stained mid-sagittal sections of E18.5 brains with the corresponding genotypes and all the functional En allele profiles indicated at the top. Asterisks indicate forming fissures. Black arrows indicate truncated inferior colliculus. The inset in F shows the lateral Cb tissue that forms in the En1^-/- mutants.