Fig. 4: Ablation of ensheathing glia causes compensatory growth and increased proliferation of astrocyte-like cells.

Representative images are shown. a–f Third instar larval brains stained for Rumpel (green, expressed by ensheathing glia), Nazgul (magenta, expressed by astrocyte-like cells) and HRP (blue, neuronal membrane marker). a Maximum projection of a confocal stack of a control larval CNS. The dashed line indicates the position of the orthogonal view shown in (c). b Dorsal view of a control ventral nerve cord. Note the regular positioning of the astrocyte-like cells (magenta). c Orthogonal section of astrocyte-like cells which are labelled using anti-Nazgul staining (white, arrowheads point to short protrusions). d, e Upon ablation of the ensheathing glia [UAS-rpr; 83E12-Gal4^AD; repo-Gal4^DBD, UAS-hid], Rumpel expression is greatly reduced. The dashed line indicates the position of the orthogonal view shown in (f). e Dorsal view of a larval ventral nerve cord following ensheathing glia ablation. The position and the morphology of the astrocyte-like cells appears disorganized. f Orthogonal section. Note, that astrocyte-like glial cells develop long cell processes that appear to encase the entire neuropil in the absence of ensheathing glia (arrowheads). g Dorsal view on a thoracic neuromere of an adult control fly. h Thoracic neuromere of an adult fly lacking ensheathing glial cells. The number of astrocyte-like cells increases. i Quantification of the number of astrocyte-like cells in the ventral nerve cord of adult flies (n = 6 brains, **p = 0.0018, unpaired t-test, two-tailed, standard deviation is indicated). j Upon ablation of the ensheathing glia, longevity is reduced (n = 200 mated females, ****p = 4.67365E-83, Log-rank test, two tailed, standard deviation is indicated). Scale bars are: a–f 50 µm, g, h 100 µm. Source data are provided as a Source Data file.