Figure 4. Zfp106 suppresses GGGGCC-mediated neurotoxicity in Drosophila.
(a) Schematics and Punnett squares from crosses of UAS-Zfp106; UAS-30R-GFP (left) and UAS-Zfp106; UAS-3R-GFP (right) transgenic flies to OK371-GAL4 flies. The Punnett squares show the number of flies that eclosed from the indicated crosses and show that expression of 30R-GFP resulted in failure of ~50% of flies to eclose (25 actual versus 54.5 predicted); this defect was completely suppressed by co-expression of Zfp106. The Chi-square test (χ2) was used to determine the significance of the differences between the observed and expected frequencies of the expected genotypes. (b) Locomotor activity of 28-day post-eclosion flies of the indicated genotypes assessed by rapid iterative negative geotaxis (RING) assay. Data are presented as the mean height climbed ± SEM. A two-way ANOVA analysis of the locomotor data revealed a significant effect of repeat expression (p<0.0001) and Zfp106 expression (p<0.01) on locomotor activity, with a significant interaction between the two factors (p<0.01); i.e. Zfp106 coexpression significantly suppresses neurotoxicity induced by expression of 30R (p<0.01) by Bonferroni's posthoc Multiple Comparison Test. n = 25 male flies for each genotype; ****p<0.0001, **p<0.01. (c, d, e) Representative NMJs of muscle 6/7 in abdominal segment A3 of third instar larvae of the indicated genotypes co-stained with anti-HRP (neuronal marker, red channel) and anti-Bruchpilot (Brp) (active zone marker, green channel). Staining of the active zone component Brp shows that expression of 30R causes a reduction in Brp-positive active zones [arrowheads in (d) compared to control in c]. Coexpression of Zfp106 suppressed the reduction in Brp-positive active zones caused by 30R [arrowheads in e compared to d]. (f) Quantification of active zones as total voxel occupancy by Brp signal at each terminal shows that Zfp106 significantly suppresses the reduction in active zone caused by expression of 30R. Data were analyzed by one-way ANOVA and Bonferroni's Multiple Comparison Test. ***p<0.001, ****p<0.0001.
Figure 4—figure supplement 1. GAL4-dependent expression of Zfp106 in Drosophila does not affect 30R-gfp mRNA levels.
