Neural Crest Flashcards
What are the 5 processes that are necessary for neural crest cell development?
Induction, EMT, delamination, migration and differentiation
Induction
The neural crest is initiated by signalling events at the edges of the neural plate where neural and non- neural ectoderm meet (i.e. the neural plate border) all along the AP axis.
Epithelial-to-mesenchymal transition (EMT)
Events at the molecular level orchestrating a change from an epithelial to a mesenchymal phenotype.
Neuroepithelium cells are in tight contact, but neural crest cells must reduce their cell contacts and take on a mesenchymal phenotype
EMT is stimulated in cells in the border plate neuroepithelium by the Bmp and Wnt cascade
Marked by the expression of TFs Snail2 and Foxd3.
Epithelial-to-mesenchymal transition (EMT)
A series of events at the molecular level orchestrating a change from an epithelial to a mesenchymal phenotype.
Cells in the neuroepithelium are in tight contact with their neighbors. To leave the neuroepithelium, neural crest cells must reduce their cell contacts and take on a mesenchymal phenotype.
Bmp and Wnt cascade induces EMT in the neural crest cells 2 key EMT transcription factors: Snail2 and Foxd3 E-cadherin expression is down regulated
Migration
The cranial neural crest cells migrate underneath the ectoderm in a ventral direction to populate the fronto-nasal process and the pharyngeal arches.
What signalling molecules repel cranial neural crest cells during their migration?
Hox homeodomain transcription factors
What is a poised chromatin state?
Bivalent chromatin marks keep neural crest cells in a “poised state” which maintains their multipotency. This is very late in development for such a large degree of flexibility to persist.
What is the current model for neural crest cell fate determination?
Just EMT > migrating progenitors with competing transcriptional modes > lineage specification (aka bifurcation)
