Lecture 5 - Dorsalisation

Question 1

posterior regions/ future posterior PNS

Answer 1

• fewer progenitor types
• few surrounding tissues
• a long structure making it easier to manipulate experimentaly and examine

Question 2

third category of cell

Answer 2

forms at the edge of the neural plate - called neural plate border cell to seperate neural plate from epidermis. they develop PNS

Question 3

in neurulation the medio-lateral axis becomes…

Answer 3

the dorso-ventral axis. lateral becomes dorsal and medial becomes ventral

Question 4

what cells do neural plate cells give rise to?

Answer 4

neural crest cells which forms the PNS

Question 5

formation of neural plate border cells

Answer 5

form in response to medium levels of BMP signalling. formed at the neural epidermis boundary

Question 6

where do neural plate border cells extend

Answer 6

around the edges of the neural plate at the lateral edges and come to lie at the dorsal edges of the neural tube after neurulation.
they rise up and sit at the dorsal aspect of the neural tube

Question 7

roof plate cells

Answer 7

cells from the neural border that do not become neural crest cells which are important for patterning and differentiation of neural identity

Question 8

Msx (transcription factor)

Answer 8

expressed by neural plate border and induced at medium levels of BMP signalling

Question 9

other transcription factors that are upregulated in neural plate border cells

Answer 9

c-Myc: governs cell prolifertaion and when mutated will give cancer
Id: genes gives the neural plate border cells into proliferative cells and stem-like potential
,Snail

Question 10

neural crest cell TFs upregulate a further set

Answer 10

promotes epithelial-mesenchymal cell transition

Question 11

neural crest cell migration (4th germ layer)

Answer 11

they form a huge amount of different types of cells in the body including, melocytes and schwann cells
- give rise to cells of PNS and enteric nervous system

Question 12

determination of different cell types

Answer 12

1. position of origin neural crest cells (Hox genes)
2. time of generation of neural crest cells
3. migratory pathway and signals encountered

Question 13

neural crest cells migrate into somites

Answer 13

because of the inhibitory molecule in the somite. these are blocks of tissue

Question 14

neural crest cells that do not go into somites

Answer 14

form dorsal route ganglia which contain sensory neurons

Question 15

somites that go in between the neural tube and somites

Answer 15

become sympathetic or parasympathetic ganglia

Question 16

bilateral symmetry

Answer 16

along dorsal-ventral axis there are specific classes of nerves born around the lumen and at specific levels of dorsal-ventral axis

Question 17

roof plate cells upregulate

Answer 17

BMPs and secreted locally into unpatterned neural tube. induce expression of transription factors e.g. Pax genes

Question 18

Pax transcription factors

Answer 18

act intrinsically to cause neural tube progenitors to acquire ‘dorsal identities’
Pax genes also induce BMPs so initiate a relay of BMP signalling cells in dorsal neural tube

Question 19

morphogen

Answer 19

secreted signal from source cells

Question 20

BMPs coming from roof plate

Answer 20

act as morphogens to induce different types of dorsal cells. roof plate cells express many different BMPs to induce a particular dorsal cell type

Question 21

patterning occurs because of..

Answer 21

different BMPs induce different cell types