Ataxin-2 is essential for neurodevelopment, locomotion, and viability in Drosophila
(A–C) (A) Atx2 depletion impairs Central nervous system development. Example images of control and elav > Atx2 RNAi CNS from Drosophila third instar larvae. Scale bar 100 μm (B). Illustration showing VNC length and body length measurements (C). Length of VNC normalized to body length. (Control ratio = 0.11 ± 0.009, Atx2 RNAi ratio = 0.08 ± 0.003, n = 8 control and 10 Atx2 RNAi animals, p = 0.0006).
(D) Atx2 depletion decreases axon length. Example images of control and elav > Atx2 RNAi CNS from Drosophila third instar larvae.
(E) Illustration showing example of axon tracing (magenta) in the VNC (cyan).
(F) Axon length in VNC normalized to VNC area (Control = 0.018 ± 7x10−4, Atx2 RNAi = 0.013 ± 1.3x10−3, n = 8 control and 10 Atx2 RNAi animals, p = 0.006).
(G) Atx2 depletion decreases dendrite development. Example images of DA neurons in control and elav > Atx2 RNAi neurons. Scale bar, 50 μm.
(H) Dendrite length per cell in control and elav > Atx2 RNAi neurons (Control = 4500 μm ± 644, Atx2 RNAi = 1290 μm ± 134, n = 11 control and 11 Atx2 RNAi animals, p < 0.0001).
(I) Sholl analysis of control and elav > Atx2 RNAi neurons DA neurons showing the number of intersections with distance from soma (n = 6 control and 4 Atx2 RNAi animals).
(J) Atx2 depletion decreases brain lobe area. Example images of control and elav > Atx2 RNAi CNS from Drosophila third instar larvae. Scale bar, 100 μm.
(K) Size of brain lobes in control and elav > Atx2 RNAi brains (Control = 34,662 μm2 ± 1897, Atx2 RNAi = 16,198 μm2 ± 1128, n = 23 control and 20 Atx2 RNAi brains, p < 0.0001).
(L) Area of photoreceptor projections normalized to brain lobes in control and Atx2 RNAi brains (Control = 0.205 ± 0.01, Atx2 RNAi = 0.035 ± 0.003, n = 23 control and 20 Atx2 RNAi brains, p < 0.0001).
(M) Atx2 depletion impairs locomotion. Example crawling tracks of control and elav > Atx2 RNAi third instar larvae. Scale bar = 10 mm.
(N) Crawling velocity of control and elav > Atx2 RNAi third instar larvae (Control = 0.71 mm/s ± 0.05, Atx2 RNAi = 0.03 mm/s ± 0.003, n = 12 control and 12 Atx2 RNAi animals).
(O) Atx2 depletion is lethal at the pupae stage. Percentage of adults eclosing from pupae cases (Control = 99%, Atx2 RNAi line 1 = 0.0%, Atx2 RNAi line 2 = 0.0%). Data are presented as mean ± standard error. ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001.