FIGURE 12.

Live imaging after dI1 neuron‐specific knockdown can be used to visualize mutant axons in intact spinal cord preparations. (a) Schematics depicting the plasmid constructs used to knockdown Fzd3 in dI1 neurons. A plasmid expressing a microRNA against luciferase (mi2Luc) was used as a control. (b) Time‐lapse sequence showing a dI1 commissural axon turning caudally instead of rostrally at the contralateral floor plate (FP) border after silencing Fzd3 (black arrowheads). (c) Time‐lapse sequence showing a dI1 commissural axon stalling at the contralateral FP border after silencing Fzd3 (black arrowheads). The growth cone kept remodeling but was not able to turn in either direction. (d) Time‐lapse sequence showing dI1 axons expressing a microRNA against luciferase. These axons were not impacted and after exiting the FP they all turned rostrally (black arrowheads). Dashed black line represents the FP exit site. r, rostral; c, caudal. Scale bars: 10 μm