<i>MZoptn</i> embryos have defects in the migration of neural crest cells.

<p><b>A–J.</b> Compressed z-stacks of WT (A, C, E, G, I) or <i>MZoptn</i> (B, D, F, H, J) embryos. Embryos are mounted laterally (A–H) or ventrally (I, J) with anterior to the left. <b>A, B.</b> α-acetylated alpha-tubulin staining of axon tracts in 25 hpf embryos. The <i>MZoptn</i> embryos have normal axon pathfinding (arrows). <b>C, D.</b> α-SV2 staining of spinal motor axons in 2 dpf embryos. These axons are guided normally in <i>MZoptn</i> embryos (arrows). <b>E, F.</b> GFP labeled endothelial cells in 2 dpf embryos show that intersegmental vessels are patterned correctly in <i>MZoptn</i> embryos (arrows). <b>G, H.</b> GFP labeling of neural crest cells in 23 hpf embryos. The ventrally directed streams of cells (arrows) in the trunk are in the right location, but the width of the streams is wider in <i>MZoptn</i> embryos along the anterior-posterior axis (horizontal bars correspond to width of above stream). <b>I, J.</b> GFP labeling of neural crest cells that are contributing to the jaw cartilage in 4 dpf embryos. The elements of the jaw cartilage in <i>MZoptn</i> embryos appear normal (arrows), including Meckel’s cartilage (m), palatoquadrate (pq), ceratohyal (ch), hyosympathetic (hs), ethmoid plate (ep) and ceratobranchials (cb). <b>K.</b> Quantification of the width of the neural crest streams in G, H. * indicates p≤0.05.