Fig 7

Spiral fiber axon guidance is partially independent from Mauthner development A) Quantification of percent of twenty acoustic stimuli that resulted in a fast escape (latency <17 ms). All images and quantifications in figure are of 5 dpf larvae. n = 55 celsr3 siblings, 51 celsr3 sib;fzd3a^-/-, 56 celsr3^-/-, 92 celsr3^-/-;fzd3a^-/+, 45 celsr3^-/-;fzd3a^-/-. B) Mauthner cell number in larvae from (A). n = 53 celsr3 sib;fzd3a^-/- (100% 2 M-cells), 55 celsr3^-/- (15% 1 M-cell, 85% 2 M-cells), 86 celsr3^-/-;fzd3a^+/- (7% 1 M-cell, 93% 2 M-cells), 45 celsr3^-/-;fzd3a^-/- (36% 0 M-cells, 33% 1 M-cell, 31% 2 M-cells). C) Escape C1-bend ratio for larvae from (A) with two Mauthners (B) that performed at least six fast escapes in response to 20 acoustic stimuli, normalized so all fish turning only one direction, left or right, appear at the same y position. n = 53 celsr3 siblings, 48 celsr3 sib;fzd3a^-/-, 41 celsr3^-/-, 71 celsr3^-/-;fzd3a^-/+, 10 celsr3^-/-;fzd3a^-/-. D) Mauthner cell number in control (no hoxb1a:Gal4, UAS:fzd3aΔC/hoxb1a::fzd3aΔC transgenes) and hoxb1a::fzd3aΔC larvae. n = 28 control (100% 2 M-cells), 52 hoxb1a::fzd3aΔC (12% 0 M-cells, 27% 1 M-cell, 62% 2 M-cells). E) Quantification of percent of twenty acoustic stimuli that resulted in a fast escape (latency <17 ms). n = 30 control, 65 hoxb1a::fzd3aΔC. F) Escape C1-bend ratio for larvae from (E) with two Mauthners that performed at least six fast escapes in response to 20 acoustic stimuli, normalized so all fish turning only one direction, left or right, appear at the same y position. n = 23 control, 27 hoxb1a::fzd3aΔC. G,H) j1229a:GFP labels Mauthner cells and spiral fiber neurons in hoxb1a::fzd3aΔC larvae while α-S100B labels glia. Yellow brackets indicate correctly positioned GFP+ spiral fiber axons at the Mauthner AIS, while white dashed brackets indicate displaced spiral fiber axon caps, due to either an absent Mauthner (G) or mispositioned Mauthner AIS (H). Yellow arrowheads in (H) denote aberrant path of left Mauthner axon, which continues posteriorly out of the Z-range displayed. Scale bars = 20 μM, Z-projection (ventral anterior range and dorsal posterior range for GFP, for clarity; division marked by dotted line). I) Quantification of “ectopic caps,” as in Fig 3O and 3P. In brain hemispheres with no Mauthners, any large Kv1.1 accumulations were considered “ectopic” since no endogenous Mauthner AIS was present. n = 16 control hemispheres, 60 hoxb1a::fzd3aΔC hemispheres with Mauthners, 32 hemispheres without Mauthners. J) Quantification of anterior-posterior position of ectopic caps from (K), as in Fig 3Q and 3R. n = 32 hoxb1a::fzd3aΔC ectopic caps in hemispheres without Mauthners.