Fig. 3

Expression of GR100, and to a lesser extent GA100, in Drosophila adult neurons is sufficient to increase nucleolar volume in inclusion-bearing neurons. a Representative images of Drosophila brain expressing GR100 or GA100 in adult neurons using the elav-GeneSwitch (elavGS) driver immunostained for the nucleolar protein fibrillarin (FIB, red), the dipeptide repeat (DPR) protein poly(GR) or poly(GA) (green), with DAPI nuclear stain (blue); typical poly(GR) and poly(GA) inclusions are arrowed. Scale bar represents 2 μm. b, c Quantification of neuronal nucleolar volume determined by fibrillarin immunoreactivity. Median nucleolar volume in Drosophila adult neurons expressing GR100 was significantly larger in neurons bearing poly(GR) inclusions (GR+) than in neurons without inclusions (GR-) (b). Using the same scale as in b, the median nucleolar volume increase in Drosophila adult neurons expressing GA100 is not apparent, highlighting the difference in magnitude of the changes; magnifying the scale (inset), reveals nucleolar volume was significantly larger in neurons bearing poly(GA) inclusions (GA+) than in neurons without inclusions (GA-) (c). Controls in b and c are Drosophila transgenic for DPR proteins that were not induced for gene expression. Each dot represents an individual fly, grey lines link medians from the same individual fly in neurons with or without DPR protein inclusions, and average and SEM are shown as long and short horizontal bars, respectively. Significance was determined by paired regression analysis: ***p < 0.001. Genotypes were: w; UAS-GR100/+; elavGS/+ (elavGS > GR100), w; UAS-GA100/+; elavGS/+ (elavGS > GA100)