Representative transverse sections taken through the chick midbrain followed by immunohistochemistry for Annexin A6 (A, red) and the migratory neural crest cell marker HNK-1 (B, green), with a corresponding merge image (C). A higher magnification image of the boxed region in (C) is shown in (C′). The caret and arrowhead indicate Annexin A6 and HNK-1 expression, respectively. Annexin A6 expression is lost in migratory neural crest cells (B, C′, arrowhead). The neural tube (NT) still expresses Annexin A (A, caret). DAPI (blue) labels cell nuclei. Scale bar, 50μm (A–C) and 125μm (C′). Ectoderm is denoted by e.