Figure 6. PR50 expression is neurotoxic in Drosophila melanogaster.
(A) Expression of C9ORF72 RAN proteins in Drosophila eyes. PR50 expression causes complete degeneration of the eyes. (B) mRNA of the DRPs was measured by in the eyes of the different fly lines by qPCR analysis (ANOVA; Kruskal-Wallis test; P=0.4373). A wild type, non-transgenic fly strain (w1118) was crossed with the GMR-GAL4 strain to rule out non-specific qPCR amplification reactions of the different DRP50 mRNAs. (C) Quantification of eye phenotypes. PR50 expression produces a significant toxic effect relative to the other RAN products and the control (**P<0.001; one-way ANOVA). (D) PR50 expressors do not develop successfully to adulthood. Viability of F1 flies that express RAN proteins is measured relative to viability of F1 flies that carry the TM6b balancer chromosome, which are produced in the same cross. (E) Flies that express PR50 in motor neurons are morphologically normal despite being trapped in the pupal case. The pupal case of the trapped PR50 expressor has been removed for this picture. The folded wings and legs are characteristic of the pupal state. (F) Expression of C9RAN dipeptide mRNAs is equally expressed in OK371-GAL4 motor neuron expressor Drosophila larvae (ANOVA; Kruskal-Wallis test; P=0.1251). (G) Western blot showing expression of C9ORF72 RAN proteins in Drosophila muscle tissue. (H) Subcellular localization of GFP tagged C9ORF72 RAN proteins in motor neurons of Drosophila larvae. Lamin staining delineates the nuclear envelope.