SOX10 cis-regulatory element drives specific reporter expression in the migratory cranial neural crest. (A) Neural crest specifier gene, SOX10, is expressed by all migrating neural crest cells. (B) A chicken embryo electroporated with Sox10E2 enhancer has GFP expression in migratory CNC at HH10. (C,C′) Transverse sections of HH10 chicken embryo electroporated with Sox10E2:eGFP plasmid. GFP+ cells are also immunoreactive for the HNK-1 epitope. (D–F) Colocalization of GFP+ cells and endogenous SOX10 confirms specificity of Sox10E2 enhancer in the CNC. (G–J) Confocal imaging confirms that of all electroporated cells (red), only the ones with SOX10 positive nuclei (blue) express GFP. (K–M) Time-lapse imaging of a chicken embryo electroporated with Sox10E2:eGFP demonstrates the extensive movements of cranial neural crest in the embryonic head (see Supplemental Movie 1). (NC) Neural crest; (R3) rhombomere 3; (OV) otic vesicle.