Just after neural fold fusion to form the neural tube, neural crest cells detach from the neural crest, a transient structure located in the dorsal region of the neural tube. Neural crest cells migrate and differentiate into many structures and cells. But the underlying controls of this detachment and initiation of emigration are unknown. Neural crest cells are usually not morphologically distinct from the adjacent neural epithelium (neural tube) and epidermal ectoderm (epiblast) flanking them. We are combining morphological and immunohistochemical approaches to study neural crest cells in their early stage of detachment from the neural crest.

Hamburger and Hamilton (1951) stages 9 to 12 White Leghorn chick embryos. Fixation in 2.5% glutaraldehyde - 0.5% tanic acid and postfixation in 1% osmium tetroxide. Embryos contrasted in bloc using uranyl acetate and embedded in araldite. Semithin transversal sections stained with toluidine blue for light microscopy. Ultrathin sections contrasted with lead citrate.