Fig. 2. schizo interacts with frazzled and netrin. Whole-mount antibody staining of stage-15/16 embryos using BP102 and subsequent HRP immunohistochemistry. Anterior is to the left. (A) Wild-type embryo. (B) Homozygous schizo^U112 mutant embryos have reduced commissures. (C) Df(1)netrin/schizo^U112 double-mutant embryo lacks most of the commissures compared with schizo^U112 mutants. (D) In a frazzled^23H9/schizo^U112 double-mutant embryo the axons cannot respond to the attractive signal secreted by the midline cells and almost all commissures are missing, indicating that schizo acts independently of the netrin pathway.