Fig. 5. JAK/STAT signal is required for the production of proper number of medulla neurons and lamina formation. (A,B) Mid L3 optic lobes of wild type (A) and hop² (B). NE cells are marked by Arm (Blue) and NBs by Dpn (magenta). Both NE cells and NBs expressed high levels of Arm and Dpn in the hop² optic lobe (B), while only cells at the transition from NE cells to NBs express both in the wild type (A). Broken white line in B indicates the border between optic lobe and central brain. (C-F) Late L3 optic lobes of wild type (C,E) and hop² (D,F). (C,D) In hop² mutant, NBs (Dpn, magenta) disappeared, neurons (Elav, blue) were fewer and lamina (Dac, green) was disrupted. (E,F) In hop² mutant optic lobe, most neurons expressing Elav also express ap-lacZ, which is a marker for the medulla neurons, as in the wild type (F, compare with E). Broken white line in F indicates the border between optic lobe and central brain.