DAN is expressed by the paraxial mesoderm adjacent to the cranial neural tube. (A) Maximum projections of DAN (red) and FoxD3 (green, neural crest marker) expression in whole embryos at HH St 10, 11, and 12 (n = 10, 12, and 4 embryos, respectively). DAN is expressed in the paraxial mesoderm in the cranial region and segmented in the somites in the trunk regions. (B) Single z planes of DAN and FoxD3 expression in the paraxial mesoderm and the developing otic vesicle (OV) at the axial level of the r4 neural crest cell stream. DAN in expressed by the mesodermal cells immediately bordering the neural crest cell stream. (C) Same images as shown in B, except with DAN expression only. (D) Transverse section of DAN and FoxD3 expression at r3 axial level at HH St 12. DAN is expressed by the paraxial mesoderm. (E) Transverse section of DAN and FoxD3 expression at r4 axial level at HH St 12. DAN is expressed by the paraxial mesoderm and may limit the migrating neural crest cells (asterisks) to the dorsolateral pathway. DAN is also expressed in the thickening ectoderm associated with otic vesicle development. (F) Mean intensity of DAN (red) and FoxD3 (green) expression at HH St 10, 11, and 12 measured adjacent to the neural tube (NT) from mid-r3 to mid-r5 as shown in images on the right (white lines). (G) Width of FoxD3 and DAN expression measured as the distance from the edge of the neural tube to the end of expression over time (hours and HH stages shown). Neural crest cells initially migrate into but eventually migrate past the DAN-rich region (Stage 11–12). The dashed FoxD3 line is predicted neural crest migration at later stages. Bars: (A) 200 µm; (B–E) 50 µm. N, notochord; L, length.