Diverse axonal pathway defects encountered in the VNC of <i>n-syb</i>, <i>snap-25</i>, and <i>Ti-VAMP</i> mutant embryos.

<p>(A-D) Stage 16 embryos were stained with anti-FasII to mark all FasII-positive axons and to better observe longitudinal axonal pathway defects. A, wt embryo showing the three FasII-positive longitudinal connectives. B, <i>SNAP-25</i> mutant embryos, representative of defasciculation (arrow) and fascicle collapse (arrowhead) phenotypes. C, <i>nSyb</i>^{<i>d02894</i>} mutant embryos, representative of midline crosses (arrow) and defasciculation phenotypes (arrowhead). D, <i>Vamp7</i> mutant embryos showing mild defasciculation phenotypes (arrow). (E) Quantification of the number of axon guidance defects encountered in <i>nSyb</i>, <i>SNAP-25</i>, and <i>Vamp7</i>/<i>Ti-VAMP</i> mutants in comparison with the background defects in the wt.(F) Quantification of the diverse axonal guidance defects encountered in <i>n-syb</i>, <i>Snap-25</i>, and <i>Vamp7/Ti-VAMP</i> mutants in comparison with the background defects in the wt. (G-J) Stage 16 embryos were stained with BP102 antibody to mark all axons in the VNC. G, wt embryo showing a detail of 6 segments with its anterior and posterior commissures. H, <i>Snap25</i> mutant embryos, representative of fuzzy commissures (arrow) and thinning of longitudinals (arrowhead) phenotypes. I, <i>nSyb</i>^{<i>d02894</i>} mutant embryos, representative of thinning of longitudinals (arrow). J, <i>Vamp7</i> mutant embryos showing mild thinning of longitudinals phenotype (arrow). (K) Quantification of the two axonal guidance defects encountered in SNAP<i>-25</i>, <i>n-syb</i> and <i>Vamp7/Ti-VAMP</i> mutants in comparison with the background defects in the wt.