Figure 8

Figure 8 Selective regulation of spastin activity by TTLLL11 controls zebrafish motor circuit wiring and larval motility.

(A) Upper panels: Immunolabelling of sMN axon tracts using Zn-5 antibodies in 72-hpf Tg(Hb9:GFP) larvae injected with MO^Ctl (n = 69), MOsp^ATG (n = 79) or co-injected with MOsp^ATG and mouse TTLL6 (n = 63) or TTLL11 (n = 78) mRNAs. Dotted lines delineate lateral myosepta. Lower panels: Tracking analysis of 72-hpf larvae injected with MO^Ctl (n = 71), MOsp^ATG (n = 90) or co-injected with MOsp^ATG and mouse TTLL6 (n = 98) or TTLL11 (n = 124) mRNAs in a touch-escape response test. Each line represents the trajectory of one larva after touch stimulation while the distance between two dots indicates the distance covered by a larva between two consecutive frames. Scale bar: 5 mm. (B–D) Quantifications of the sMN (B) and locomotor defects (C, D) of larvae analysed in (A) and pooled from three independent experiments. (B) Mean number of abnormal rostral nerves. (C, D) Mean swimming speed (C) and covered distance (D). (E) Immunolabelling of sMN axons in 72-hpf sp^+/+ (n = 52), sp^C68X/C68X (n = 34) and sp^C68X/C68X larvae injected with mouse TTLL6 (n = 47) or TTLL11 (n = 49) transcripts using Zn-5 antibody. (F, G) Quantifications of rostral nerve defects in larvae analysed in (E) and pooled from three independent experiments. (F) Percentage of larvae with rostral nerve defects. (G) Mean number of abnormal rostral nerves (i.e., defasciculated or missing) per larva. (A, E) Full and empty arrowheads, respectively, point at normal and defasciculated/missing rostral nerves. Full arrows in (E) indicate caudally oriented “rostral” nerves. Scale bar: 50 μm. (B, F, G) Non-blind quantifications were performed on 24 spinal hemisegments located around the yolk tube per larva. (B–D, G) Violin Plots; horizontal bars indicate the median ± the 1st and 3rd quartiles. Kruskal–Wallis ANOVA test with Dunn’s post hoc test. (F) Chi² test. P values are displayed on graphs. Source data are available online for this figure.