Fig. 8: ß_H-Spectrin shows a polar distribution in ensheathing glia.

Representative images are shown. a Schematic view of the karst locus. Transcription is from left to right. Seven different karst mRNAs are generated from two promoters (P1, P2) as indicated (kst-RA - RH). The ß_H-Spectrin proteins PE and PG differ in a C-terminal exon indicated by brackets. The position of two MiMIC insertions and the EP insertion used for gain of function experiments is indicated, the blues line denotes the position of the peptide used for immunization. b Confocal view of the surface of a third larval instar brain of a kst^{MiMIC03134::GFP} animal that expresses mCherry in all ensheathing glia [83E12-Gal4, UAS-CD8::mCherry]. The dashed line indicates the position of the orthogonal view shown in (c, d). Expression at the blood–brain barrier forming subperineurial glia (arrows) and at the apical domain of the ensheathing glia (arrowheads) can be detected. For quantification see (k). e Similar view as shown in (b) of a control larva stained for Kst expression using a polyclonal antiserum. The dashed line indicates the position of the orthogonal view shown in (f). f Localization of Kst protein is weakly seen in the blood–brain barrier (arrow) and the ensheathing glia (arrowhead). g Orthogonal view of a kst^{MiMIC03134::GFP} animal expressing kst^dsRNA in the ensheathing glia (EG) [83E12-Gal4, UAS-kst^dsRNA]. Expression of Karst in ensheathing glia cannot be detected anymore (asterisk). Expression in the blood–brain barrier is unaffected (arrow). h, i The Trojan Gal4 element in kst^MiMIC03134 directs Gal4 expression in the kst P2 pattern. Lamin::GFP localizes to ensheathing glial nuclei (arrows), some cells of the blood–brain barrier (arrowheads) and some cells in the position of tracheal cells (asterisks). j Quantification of Karst localization in different membrane domains of ensheathing glial cells, quantification as described in Fig. 6. Scale bars are 50 µm except d: 10 µm. Source data are provided as a Source Data file.