L6 - Dorsalisation Flashcards
What is secreted from the node/organiser … give an example of one
BMP antagonists
e.g. chordin
What does the secretion of BMP antagonists cause the induction of
Induction of neural plate formation
Where there is an INTERMEDIATE level of BMP signalling what is this zone known as
Neural plate border
Found between the neural plate and the non-neural ectoderm
3 crucial points of the neural plate border
Crucial for neural crest formation - and the formation of the PNS
Crucial for the formation of the root plate cells and the patterning of the dorsal neural tub
Crucial for complete closure of the neural tube
What does neural crest formation and neural tube patterning happen before
The expression of Shh in the notochord
STAGE 1] An early _______ established due to the ________ between BMP signalling and antagonism. This _____ ______ _______ then begins to express specific transcritpion factors such as _____
Border
Balance
Neural plate border
Msx1
At the neural plate border BMP signalling level is
Intermediate
STAGE 2] Other signals (____ and ____) act together with _____ to turn _____________
WNT and FGFs
Msx1
Turn on other transcription factors
What signals are from the preaxial mesoderms
WNTs and FGFs
What signalis from the non neural ectoderm
WNTs
Msx1 acts in a ____________________ and WNTS and FGFS act in a _______________ to cause the activation of ________ and ________
Intrinsic - cell autonomous
Extrinsic - cell non-autonomous
PAX3 and ZIC1
STAGE 3] ____ signals acts with the transcription factors of the ________________ to upregulate further TFs - (_____,______,_____) which are characteristic of neural crest cells
WNT
Neural plate border
c-myc, Snail, ID
PAX3 and ZIC1 act in a ____________
WNTS act in a __________
To cause the upregulation of ______ and ______
Extrinsic - cell non-autonomous
Intrinsic - cell autonomous
Snail and FoxD3
Snail is responsible for
Promoting cell survival
Promotion of cells to undergo and epithelial mesenchymal transition
c-myc is an
Upregualtion will causes
Oncogene
Proliferation of cells
ID will cause
Stem like behaviour of cells (multipotency)
STAGE 4a] In response to _______ and ______ genes that control _______ , _______ and ________ are activated
c-myc and SOX9
Survival, multipotency and survival
Cascade of expression and effect of c-myc
c-myc –> ID –> Multipotency and proliferation
Cascade of expression and effect of SOX9
Sox9 –> Snail –/ Cell death (promotes cell survival)
Stage 4b] At the same time there is an upregulation of genes which promote ____________. This then causes the _________ of the _______ _______ cells and ____________
Epithelial –> Mesenchymal transition
Delamination
Neural crest
Migration away
Neural crest cells are often descirbed as
The fourth germ layer
What sort of cells do the neural crest cells differentiate into
PNS Adrenal medulla Melanocytes Facial cartilage Dentin of the teeth
What are the different cell types of the neural crest cell formed by
Position of origin (due to HOX gene)
Time of generation by the cells
Migration pathway and the signals they encounter en route or at the target
Describe how the dorsal route ganglion is formed
NCCs usually at the posterior of the somite and force to move into the anterior of the somite by pissoffin
Describe how the sympathetic and parasympathetic NS are formed
NCCs reach are beneath the notochord and the aorta
Do all NCCs delaminate
No, some stay and form the roof plate clls
What are the roof plate cells crucial in
Through to play a part in the fusion of the two sides of the neural tube
What was previously thought to act as a morphogen
BMP from the roof plate
What is now thought to be the way in which the roof plate signals
Different BMPS secreted from the roof plate ==> each BMP induces a different dorsal cell type
What are the different progenitors on the dorsal side of the neural tube
P1 –> P6
What are the cell types which differentiate dorsally
Roof plate cells
Neural crest cells
Different classes of dorsal sensory relay interneurones
