Study Questions – Lecture Set 14 (Neural Crest)
1. What is the origin of the neural crest cells? How are they specified and into what
four general cell types can they differentiate?
The neural crest is derived from the ectoderm. It is often considered as the fourth germ
layer, a transient structure that can undergo epithelial to mesenchyme transition and
become migratory. They can become:
-neuron and glia of peripheral nervous system
-epinepherine producing cells of the adrenal glands
-skeletal and connective tissue in the head
Their specification is determined by neural plate inductive signals BMP and Wnts. If Wnt
turns on BMPs and Wnt stays on, the neural crest is established.
2. FoxD3, snail, twist, and Sox9 are examples of neural crest specifier genes. What
events are associated with expression of these genes?
Events such as epithelial-to-mesenchyme transition and delamination are associated with
the expression of these genes. Without Sox9, the cells will undergo apoptosis when they
3. There are four general regional fates of neural crest cells according to their position
of origin along the anterior/posterior axis. What is the name each region and which
region is the only one that specifies bone forming cells (osteoblasts)? What general
developmental class of genes is responsible for specifying these different regions?
The four regions are:
-cranial: cartilage and bones, neurons and glia in face, thymic cells, odontoblasts/teeth,
middle ear bones and jaw
-cardiac: melanocytes, neurons cartilage, connective tissue, musculature and connective
tissue of large as arteries and heart septum
-trunk: dorsal root ganglia/sensory neurons, sympathetic ganglia, adrenal medulla, nerve
clusters around aorta and melanocytes
-vagal and sacral: enteric ganglia (for peristalsis in gut)
Cranial region specifies the bone forming cells. Hox genes are responsible for specifying
these different regions.
4. Outline the possible fates of neur