Differentiation of the Neural Crest and the Epidermis
Formation of the
Neural Crest Cells
a. Neural crest cells are derived from cells found at the
during neurulation (Fig. #1)
b. Presumptive epidermal cells express
and neural tube cells express
Some cells, initially expressing N-cadherin and N-CAM, downregulate their production
of these molecules and upregulate the
gene, which encodes a specific transcription factor.
These cells become migrating neural crest cells.
c. Experiments indicating
gene involvement in neural crest migration.
1. Determination of the
mRNA and Slug protein by
Indicates slug mRNA and protein are found in neural crest cells.
Incorporating into the embryo anti-sense RNA to
anti-sense RNA binds to
mRNA and prevents translation of
mRNA into Slug
protein, so little or no Slug protein is made.
This addition of anti-sense
prevented migration of neural crest cells, indicating the importance for neural crest
migration of the Slug protein.
d. Neural crest cells migrate from the space between the presumptive epidermis and the neural tube.
e. Neural crest cells are among the most pluripotent cells, developing into a wide variety of cell
As they migrate and divide, they differentiate and become less pluripotent (Figs, #3, #4)
Developmental Fates of Neural Crest Cells (Figs. #5.1, #5.2)
a. General regions/functional domains within which they migrate.
Cephalic neural crest
(head): bones, cartilage, neurons, glia and connective tissue of the
face, tooth primordia, thymic cells, jaw and inner ear cartilage
Trunk neural crest:
melanocytes of skin; neurons in the dorsal root (sensory) ganglia, in the
sympathetic ganglia, and surrounding the aorta; and endocrine cells in the adrenal medulla.
Vagal and sacral neural crest
(anterior to, and posterior to trunk, respectively): neurons of
the parasympathetic ganglia, including cervical ganglia
Cardiac neural crest:
cells of the septum between the pulmonary artery and the aorta,
connective tissue and smooth muscle of large arteries near heart.
b. Specific migratory pathways of neural crest cells; example: trunk neural crest cells.
1. Neural crest cells migrate through and around
temporary segmental structures
derived from mesoderm that surround the neural tube. (Figs. #6.1, #6.2, #6.3)
2. Some neural crest cells migrate between the epidermis and the
(outer part of
somite.) (Fig. #7) These cells will become
(pigment cells in the skin.)
3. Some neural crest cells migrate in the anterior part of each somite, within the