Fig. 3. Cxcl12a/Cxcr4b signaling is required for olfactory neuron positioning. Wild-type zebrafish embryos (A), ody mutants (B,C), cxcr4b MO-injected embryos (morphants) (D), cxcl12a morphants (E) and cxcl12b morphants (F), which all carry the omp:yfp transgene, were stained with anti-GFP antibody at 24 hpf to visualize olfactory neurons. All panels show frontal views with ventral to the bottom. Two representative ody/ody embryos with mild (B) and severe (C) defects in olfactory neuron positioning are shown. Scale bar: 100 µm.