Fig. 8

Hypo-innervation induces a homeostatic increase in postsynaptic GluR abundance. a Schematic illustrating a wild type and hypo-innervated muscle 7 synapse at the Drosophila NMJ achieved by overexpression of FasII selectively on the adjacent muscle 6 (WT M7 hypo: w;tubP>stop>Gal4,UAS-FLP,UAS-CD8-GFP/UAS-FasII-PEST+;H94-Gal4,nSyb-Gal80). A compensatory increase in mEPSP amplitude is observed that maintains baseline levels of synaptic strength (EPSP amplitude). Representative mEPSP and EPSP traces of the indicated genotypes recorded are shown below. Quantification of mEPSP amplitude (b), EPSP amplitude (c), and quantal content (d) in the indicated genotypes. e Representative images of muscle 7 larval NMJs in wild type (WT) and WT M7 hypo immunostained with antibodies that recognize vGlut and the neuronal membrane (HRP). Note the reduced innervation of boutons onto muscle 7 in the WT M7 hypo condition. Right: Representative GluRIIA staining of the corresponding genotypes. An upregulation in GluRIIA levels is observed on the hypo-innervated muscle 7. Quantification of bouton numbers (f) and GluRIIA puncta intensity (g) of the indicated genotypes. Error bars indicate ± SEM. For statistical significance, an unpaired t-test was performed. **p 0.01; ****p 0.0001; NS not significant, p > 0.05