Fig. 2
Knockdown affected R-cell development only. Candidate genes were knocked down simultaneously in both R cells and WG by expressing the UAS-RNAi transgene under control of ey3.5-GAL4 and Mz97-GAL4. 3rd-instar larval eye-brain complexes were double-stained with MAb24B10 (green) and anti-Bdl (magenta). A-A”, the projection pattern of R-cell axons and WG processes in wild type (100%, n = 15). A, the section was stained with MAb24B10 only. R-cell axons migrate towards the posterior end of the eye disc (ed) and subsequently enter the optic stalk (os). After exiting the optic stalk, R1-R6 axons terminate at the lamina (la), where their expanded growth cones form a dense and continuous layer. R7 and R8 axons pass through the lamina and form a regular array of terminals within the deeper medulla layer (me). A’, the same section was stained with anti-Bdl to visualize WG. WG processes follow R-cell axons from the eye disc through the optic stalk into the lamina. BN, Bolwig’s Nerve. A”, the section was visualized with both MAb24B10 and anti-Bdl staining. B-B″, a third-instar eye-brain complex in which CadN was simultaneously knocked down in both eye disc and WG. CadN knockdown disrupted the termination pattern and the morphology of R-cell axons (B and B″), but did not affect WG development (B’ and B″). Scale bar: 20 μm