L11- Origins and Derivatives of the Neural Crest

Question 1

What are neural crest cells?

Answer 1

Migratory embryonic cells that move around to colonise the body and form different types of cells such as neurons, bone, pigment, cartilage and connective tissue

Question 2

How does BMP activity impact the formation of the neural plate?

Answer 2

Ventral mesoderm secretes BMP
Spemann organiser (dorsal) secretes BMP antagonists
This creates a BMP gradient
○ High BMP= epidermis
○ Low BMP= neural plate
○ Intermediate (interaction)= Neural crest

Question 3

What two signals are required for neural crest formation?

Answer 3

1. Intermediate levels of BMP

2. FGF signals from the paraxial mesoderm

Question 4

How do NCC migrate?

Answer 4

Epithelial-Mesenchyme Transition:

1. Lose epithelial cell polarity
2. Gain of mesenchymal properties
3. Acquisition of motility

Question 5

What is single cell and collective cell migration?

Answer 5

Single cell: each cell knows where to go

Collective cell: cells are only capable of finding the route as a group (NCC’s)

Question 6

What is the contact inhibition of locomotion?

Answer 6

Mechanism by which NCC’s migrate:

1. Cells collide with eachother
2. New cell-cell junction forms (transient)
3. Cells repolarise and junction disassembles
4. Cells disperse in different directions

Question 7

Why can’t NCC’s disperse?

Answer 7

Confinement- non permissive environment

○ Cells contained within group cannot escape, only cells at the leading edge can disperse

Question 8

Why don’t NCC’s move backwards?

Answer 8

Co-attraction- maintain group cohesion

○ NCC’s secrete a C3a molecule which attracts them to eachother, attraction increases in larger groups of cells.

Question 9

What is the difference between trunk and cranial NCC migration?

Answer 9

○ Cranial NCC migration depends on cell-cell interactions via CIL and CO-A (all cells have equal motility)

○ Trunk NCC migration requires leader and follower cells (leader cells have faster motility)

Question 10

What do NCC’s give rise to in the cranial and vagal regions?

Answer 10

Cranial: 
○ Craniofacial skeleton
○ Cranial ganglia
○ Teeth
○ Neurons

Vagal:
○ Enteric ganglia
○ Smooth muscle cells

Question 11

What do NCC’s give rise to in the trunk and sacral regions?

Answer 11

Trunk:
○ Dorsal root ganglia
○ Sympathetic ganglia
○ Adrenal medulla

Sacral:
○ Enteric ganglia
○ Sympathetic ganglia

Question 12

What do NCC’s give rise to at all axial levels?

Answer 12

Pigment cells