Fig. 1: Development of ensheathing glia.

Representative images are shown. a–d Dissected larval CNS of increasing age with the genotype [83E12-Gal4, UAS-CD8::GFP], stained for GFP (green), Repo (magenta) and neuronal membranes (anti-HRP, blue), anterior is up. The positions of the orthogonal section shown in a’–d’ is indicated by a dashed line. a, a’ In a stage 16 embryo ensheathing glial cells have not yet covered the neuropil (arrowheads). b, b’ First instar larval CNS. c, c’ Second instar larval CNS. d, d’ CNS of a wandering third instar larva. The arrows point towards dorsal protrusions of the ensheathing glia engulfing dorsal neurons. e MCFO labeling of ensheathing glia in third instar larva stained for the expression of V5 (green), HA (red), and FLAG and OLLAS epitopes (blue). flp expression was induced for one hour during first instar larval stage. Note that ensheathing glia tile the ventral nerve cord. f Two distinct ensheathing/wrapping glia cells cover the nerve root and part of the neuropil (arrowheads). g Ensheathing glia occupy specific territories in the neuropil. h, i Third instar larval nerve cord with the genotype [55B12-Gal4, 83E12-LexA, UAS-CD8::mCherry, LexAop-GFP]. All cortex glia cells are labelled by mCherry expression (magenta). Ensheathing glial cells are labelled by GFP expression (green). The dashed line indicates the position of the orthogonal view shown in (i). j Schematic view on a cross section through a hemineuromere indicating the position of the different glial cells. Astrocyte-like cells and ensheathing glial cells localize close to the neuropil and the axons connecting the neuropil with the periphery. The cortex glia covers lateral and ventral neuronal cell bodies. Scale bars a–i are 50 µm.