A Global In Vivo Drosophila RNAi Screen Identifies a Key Role of Ceramide Phosphoethanolamine for Glial Ensheathment of Axons
(A) lace RNAi was expressed specifically in wrapping glia (Nrv2-GAL4). mCD8-GFP (green) marks the membrane of wrapping glia and HRP (red) is used to visualize the neuronal membrane. Orthogonal sections from the non-swollen region are presented as insets. Scale 20 µm. (B) TEM micrographs of L3 larval peripheral nerve cross-sections are shown. Wrapping glia is color-coded. Axonal ensheathment is incomplete upon loss of lace function in all glia (middle) or in wrapping glia (right). Proper ensheathment of axons is observed only in control (left). Scale 1 µm. (C) Quantification of the GFP signal intensity of wrapping glial membrane was performed on merged confocal projections and t-test was used for the analysis. Scale 20 µm.. (D) Quantification of the number of unwrapped axons (8–10 nerves from 4 animals for each genotype). One-way ANOVA followed by Dunnett post hoc test was performed. All graphs represent mean values ± SD. * p<0.05 *** p<0.001. (E) TUNEL assay after lace knockdown in the wrapping glia and merged projection of the peripheral nerves are presented. TUNEL (green) positive nuclei are observed only in the positive control (after DNAse addition).