Fig. 4: Wrapping glial cells require innexins for their growth.
Third instar larval filet preparations expressing endogenously V5-tagged Ogre (a green), or endogenously V5-tagged Innexin2 (b–d green), or carrying a nrv2-GFP fusion (e–g, green). HRP (blue) labels neuronal membranes, (a, e–g) Innexin2 antibody staining is shown in red. More than ten animals were analyzed for each genotype. Representative images are shown. Scale bars are 200 µm. a In a control larva, Innexin1 (Ogre, green) and Innexin2 (Inx2, red) show overlapping localization. The boxed area is shown in higher magnification. b Upon panglial, RNAi mediated suppression of innexin2 expression no Inx2 can be detected in nerves. c Upon suppression of innexin2 expression only in the subperineurial glial cells some reduction in Inx2 can be observed. d Similar expression patterns are observed upon innexin2 suppression in wrapping glia. e Note that wrapping glial cells cover the entire width of the nerve. f Upon knockdown of ogre in wrapping glia, the differentiation of wrapping glia is affected (arrowheads). Mainly thin wrapping glial processes can be detected. Inx2 is seen in the peripheral nerves (arrows). g A similar phenotype is noted when innexin2 is suppressed in the wrapping glia (arrowheads). h Bending distribution of control [nrv2-Gal4; 90C03-Gal80/UAS-GFPdsRNA] and ogre knockdown third instar larvae [nrv2-Gal4; 90C03-Gal80/UAS-ogredsRNA]. ogre knockdown larvae show increased bending (p = 1.36E−25, t test). i The accumulated distance per minute is slightly reduced in ogre knockdown animals (p = 1.6E−19, Wilcoxon rank-sum test, n = 88 control larvae and n = 69 larvae expressing ogredsRNA). Box plot shows median (red line), boxes represent the first and third quartile, whiskers show standard deviation, red points show outliers. j Same dataset as in (i). Quantification of the coiling phenotype. The relative distribution of 300 frames long movement clips (n = 259 30 s long video clips with 300 frames each) with 0, 1–30, or 31–60 frames showing coiling. Green denotes control, red denotes larvae expressing ogredsRNA in wrapping glia. Genotypes as in (h).
