Fig. 5. schizo acts in the central nervous system (CNS) midline cells. Frontal views of dissected CNS preparations of stage-16 embryos stained for the presence of all CNS axons using Mab BP102. Anterior is up. (A) Wild-type embryo: note the regular arrangement of the Fas2-positive longitudinal fascicles. (B) The EMS-induced schizo^U112 mutation leads to a lack of commissures. (C) Following expression of schizot2 in all midline cells of a homozygous mutant schizo embryo, the mutant phenotype is rescued and commissures form normally.