The relative distribution of the ARSs within a single SPG cell. Nerve cord dissected from third instar larvae in which single glia cells were labeled with GFP and with phalloidin (e.g., arrow in A). High magnification of the borders between GFP-positive and -negative SPG cells labeled with phalloidin (B and D) or their merged images (C and E) are shown. Arrows in B and C indicate three ARSs that belong to the GFP-negative cell marked by white lines in C. Arrowheads in D and E indicate five ARSs, all of which belong to the GFP-positive SPG cell, marked by white lines in E. (F) A cross section in the nerve cord of third instar larvae carrying moesin-GFP, driven by Moody-Gal4 and stained with anti-NrxIV (red; F and G) and anti-GFP (green; F and G; arrow in F indicates the SPG layer). (G) High magnification of the region marked by the rectangle in F. The septate junction (S.J.) formed between neighboring SPG cells is marked by NrxIV staining (red; arrows). The ARSs are marked by arrowheads. (H and I) High magnification of a cross section of nerve cord dissected from larvae expressing Nrg-GFP (green; H) labeled with phalloidin (red; I). The ARSs are indicated by arrowheads, and the septate junction between neighboring SPG is marked by arrows. J–L show a cross section in Nrg-GFP–expressing larvae labeled with anti-GFP (green; K and L), phalloidin (Phall; red; J and L), and NrxIV (blue; J–L). Arrowheads indicate the ARSs, and arrows show the septate junction. (M) A scheme of the relative distribution of the ARSs, membrane convoluted loop, and septate junction deduced from our analysis.