title: Cell delamination in the mesencephalic neural fold and its implication for the origin of ectomesenchyme.
abstract: The neural crest is a transient structure unique to vertebrate embryos that gives rise to multiple lineages along the rostrocaudal axis. In cranial regions, neural crest cells are thought to differentiate into chondrocytes, osteocytes, pericytes and stromal cells, which are collectively termed ectomesenchyme derivatives, as well as pigment and neuronal derivatives. There is still no consensus as to whether the neural crest can be classified as a homogenous multipotent population of cells. This unresolved controversy has important implications for the formation of ectomesenchyme and for confirmation of whether the neural fold is compartmentalized into distinct domains, each with a different repertoire of derivatives. Here we report in mouse and chicken that cells in the neural fold delaminate over an extended period from different regions of the cranial neural fold to give rise to cells with distinct fates. Importantly, cells that give rise to ectomesenchyme undergo epithelial-mesenchymal transition from a lateral neural fold domain that does not express definitive neural markers, such as Sox1 and N-cadherin. Additionally, the inference that cells originating from the cranial neural ectoderm have a common origin and cell fate with trunk neural crest cells prompted us to revisit the issue of what defines the neural crest and the origin of the ectomesenchyme.
authors.affiliation: Institute of Molecular Cell Biology, ASTAR, 61 Biopolis Drive, 138673, Singapore.
authors.forename: Raymond Teck Ho
authors.initials: RT
authors.lastname: Lee
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nagai
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakaya
authors.forename: Guojun
authors.initials: G
authors.lastname: Sheng
authors.forename: Paul A
authors.initials: PA
authors.lastname: Trainor
authors.forename: James A
authors.initials: JA
authors.lastname: Weston
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Thiery
mesh_terms: D000818:Animals; D015820:Cadherins / Q000096:biosynthesis; D002454:Cell Differentiation; D019070:Cell Lineage; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology / Q000196:embryology*; D046149:Embryo Culture Techniques; D058750:Epithelial-Mesenchymal Transition; D008636:Mesencephalon / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D008648:Mesoderm / Q000166:cytology / Q000196:embryology*; D051379:Mice; D009432:Neural Crest / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D054258:Neural Plate / Q000166:cytology; D055748:SOXB1 Transcription Factors / Q000096:biosynthesis
chemical_list: D015820:Cadherins; D055748:SOXB1 Transcription Factors; C098693:Sox1 protein, mouse
keywords: Ectomesenchyme; Neural crest; Neural fold