neural crest cells Flashcards
what do ncc form?
Neurons and glia of PNS, cartilage and bone, connective tissue, sympatho-adrenal cells, sensory neurons and glia, pigment cells
ncc are derived from ____derm
ectoderm
how are neural plate boarder genes induced
intermediate BMP + Wnts & FGF -> neural plate boarder genes induced
_____ BMP activity = neural plate boarder
intermediate
overexpressed BMP =
ectoderm
low BMP = (neural plate border)
NP border expands
trans factors at neural plate border
Pax3/7, Msx, Zic
epithelial -> mesenchymal transition
Changes in cell-cell adhesion - Loss of tight junctions
- Loss of adherens junctions - Changes in cadherin expression
- Loss of apical-basal polarity
- Changes in cell shape
- actin cytoskeleton
- Lamellipodia and filopodia
- Changes in cell-matrix adhesion - Expression of receptors for extracellular matrix molecules
- Expression of matrix metalloproteases
- Loss of association with basal lamina
EMT promoted by
BMP and Wnt
microRNA
bind to target mrna and repress / promote translation
migration of NCC - order
- cranial
- vagal
- trunk
- sacral
failure to migrate - cranial NCC
craniofacial defecits
treacher collins syndrome: failure of ncc to migrate to brachial arch 1 to survive
trunk ncc migration
there are somites at this level
DL pathway (around); melanocytes only
V pathwway (between and through); symp gang, dorsal root gang, schwann cells, melanocytes, adrenal chromaffin cells
formation of dorsal root ganglia
ventral pathway
caudal halves of somites are inhibitory to ncc
class 3 semaphorins bind to neuropilin receptors -> INHIBIT migration
= NCC in posterior somite halves
= cell bundles = dorsal root ganglia
how do ncc migrate
Lamellipodia: respond to signals (attraction = protrusion, attachment and traction)
ENS formation -> ncc
took out vagal = no ens
saw migration of ncc through quail chick chimeras
if trunk ncc put in vagal -> wont function as well
ablating regions of nc
Ablating regions of the NC
And then seeing what doesn’t form
Can see importance for particular regions
Can’t see how cells get to locations
Or if other cells compensate for loss
Requires high skill
quail chick
Chick Quail Chimeras
Can identify cells during migration
Cells are permanently identified
Can’t image live cells in embryo
label pre migratory cells
Image cells in live embryos
Label a variable number of cells
Label different groups of cells (or in precise locations)
Labels are not permanent (Dilute out)
intrinsic markers of ncc ->immunohist and ish
Label specific genes / populations of NC
Can use antibodies to label multiple concurrently
See how specific NC genes affected from manipulation
Can only label fixed tissue (not live)
transgenic animals expressing reporter genes
Label specific genes / populations of NC
Can use antibodies to label multiple concurrently
See how specific NC genes affected from manipulation
Can only label fixed tissue (not live)
light microscopy
allows imaging of whole embryod
