L6 - Dorsalisation

Question 1

What is secreted from the node/organiser … give an example of one

Answer 1

BMP antagonists

e.g. chordin

Question 2

What does the secretion of BMP antagonists cause the induction of

Answer 2

Induction of neural plate formation

Question 3

Where there is an INTERMEDIATE level of BMP signalling what is this zone known as

Answer 3

Neural plate border

Found between the neural plate and the non-neural ectoderm

Question 4

3 crucial points of the neural plate border

Answer 4

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

Question 5

What does neural crest formation and neural tube patterning happen before

Answer 5

The expression of Shh in the notochord

Question 6

STAGE 1] An early _______ established due to the ________ between BMP signalling and antagonism. This _____ ______ _______ then begins to express specific transcritpion factors such as _____

Answer 6

Border
Balance
Neural plate border
Msx1

Question 7

At the neural plate border BMP signalling level is

Answer 7

Intermediate

Question 8

STAGE 2] Other signals (____ and ____) act together with _____ to turn _____________

Answer 8

WNT and FGFs
Msx1
Turn on other transcription factors

Question 9

What signals are from the preaxial mesoderms

Answer 9

WNTs and FGFs

Question 10

What signalis from the non neural ectoderm

Answer 10

WNTs

Question 11

Msx1 acts in a ____________________ and WNTS and FGFS act in a _______________ to cause the activation of ________ and ________

Answer 11

Intrinsic - cell autonomous
Extrinsic - cell non-autonomous
PAX3 and ZIC1

Question 12

STAGE 3] ____ signals acts with the transcription factors of the ________________ to upregulate further TFs - (_____,______,_____) which are characteristic of neural crest cells

Answer 12

WNT
Neural plate border
c-myc, Snail, ID

Question 13

PAX3 and ZIC1 act in a ____________
WNTS act in a __________
To cause the upregulation of ______ and ______

Answer 13

Extrinsic - cell non-autonomous
Intrinsic - cell autonomous
Snail and FoxD3

Question 14

Snail is responsible for

Answer 14

Promoting cell survival

Promotion of cells to undergo and epithelial mesenchymal transition

Question 15

c-myc is an

Upregualtion will causes

Answer 15

Oncogene

Proliferation of cells

Question 16

ID will cause

Answer 16

Stem like behaviour of cells (multipotency)

Question 17

STAGE 4a] In response to _______ and ______ genes that control _______ , _______ and ________ are activated

Answer 17

c-myc and SOX9

Survival, multipotency and survival

Question 18

Cascade of expression and effect of c-myc

Answer 18

c-myc –> ID –> Multipotency and proliferation

Question 19

Cascade of expression and effect of SOX9

Answer 19

Sox9 –> Snail –/ Cell death (promotes cell survival)

Question 20

Stage 4b] At the same time there is an upregulation of genes which promote ____________. This then causes the _________ of the _______ _______ cells and ____________

Answer 20

Epithelial –> Mesenchymal transition
Delamination
Neural crest
Migration away

Question 21

Neural crest cells are often descirbed as

Answer 21

The fourth germ layer

Question 22

What sort of cells do the neural crest cells differentiate into

Answer 22

PNS 
Adrenal medulla 
Melanocytes 
Facial cartilage 
Dentin of the teeth

Question 23

What are the different cell types of the neural crest cell formed by

Answer 23

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

Question 24

Describe how the dorsal route ganglion is formed

Answer 24

NCCs usually at the posterior of the somite and force to move into the anterior of the somite by pissoffin

Question 25

Describe how the sympathetic and parasympathetic NS are formed

Answer 25

NCCs reach are beneath the notochord and the aorta

Question 26

Do all NCCs delaminate

Answer 26

No, some stay and form the roof plate clls

Question 27

What are the roof plate cells crucial in

Answer 27

Through to play a part in the fusion of the two sides of the neural tube

Question 28

What was previously thought to act as a morphogen

Answer 28

BMP from the roof plate

Question 29

What is now thought to be the way in which the roof plate signals

Answer 29

Different BMPS secreted from the roof plate ==> each BMP induces a different dorsal cell type

Question 30

What are the different progenitors on the dorsal side of the neural tube

Answer 30

P1 –> P6

Question 31

What are the cell types which differentiate dorsally

Answer 31

Roof plate cells
Neural crest cells
Different classes of dorsal sensory relay interneurones