C9orf72 repeat expansions cause neurodegeneration in Drosophila through arginine-rich proteins - PubMed (original) (raw)

Fig. 2. Pure GGGGCC repeats caused toxicity via DPR proteins.

(A) Dot blot showing that 36 and 103 pure repeats generated poly-(GR) proteins while 3 pure repeats, and 36, 108 and ~288 RNA-only (RO) repeats did not. Genotypes were: w; UAS-3/hsGal4, w; UAS-36/hsGal4, w; UAS-103/ hsGal4, w; UAS-36 RO/hsGal4, w; UAS-108 RO/ hsGal4, w; UAS-288 RO/hsGal4. (B) Stereomicroscopy images of representative Drosophila eyes expressing pure or RO repeats using the GMR-GAL4 driver. 36 pure repeats were mildly toxic. 103 pure repeats showed more overt toxicity. 3 repeats and 36 and 108 RO repeats had no effect. Genotypes were: w; GMR-Gal4/+, w; GMR-Gal4/UAS-3, w; GMR-Gal4/UAS-36, w; GMR-Gal4/UAS-103, w; GMR-Gal4/UAS-36RO, w; GMR-Gal4/UAS-108RO, w; GMR-Gal4/UAS-288RO. Scale bar represents 200 µm. (C) Quantification of egg-to-adult viability showed that 36 and 103 pure repeats were lethal at higher temperatures, whereas RO repeats had no effect (Kruskal Wallis test with Dunn's multiple comparison (selected pairs), ***p<0.001, **p<0.01, *p<0.05, error bars represent SEM). Genotypes were as in (B). (D) Survival of female flies expressing repeats in adult neurons using the elav-GeneSwitch (elavGS) driver. 36 and 103 pure repeats substantially decreased survival, while 36, 108 and 288 RO repeats had no effect (p<0.0001, log-rank test). Genotypes were: w; UAS-3/+; elavGS/+, w; UAS-36/+; elavGS/+, w; UAS-103/+; elavGS/+, w; UAS-36 RO/+; elavGS/+, w; UAS-108 RO/+; elavGS/+, w; UAS-288 RO/+; elavGS/+. (E) Flies expressing 36 and 103 pure repeats survived longer in the presence of cycloheximide than in its absence (p<0.001, log-rank test). Genotypes were: w; UAS-36/+; elavGS/+, w; UAS-103/+; elavGS/+.