Lecture 6 - Ventralisation of neural tube

Question 1

two main models

Answer 1

1. Alan Turing ‘reaction-diffusion’ model
2. Lewis Wolpert ‘positional information’ French flag model

Question 2

signals as morphogens

Answer 2

depends on ‘strength’ of initial signal and different transcriptional profiles are elicited and hence different progenitor cell fates

Question 3

what do morphogens generate?

Answer 3

several discrete cellular states in response to different thresholds on concentration gradient
they are instructive in a direct manner

Question 4

ventral aspects of neural tube formation

Answer 4

intermate with notochord of posterior part of the axis

Question 5

formation of axial mesoderm

Answer 5

as it forms it expresses a new gene, Sonic Hedgehod (SHH) - this is a secreted ligand and a morphogen

Question 6

looking at SHH

Answer 6

is done by immunohistochemistry

Question 7

SHH acting as a morphogen

Answer 7

induces different progenitor cells along the dorso-ventral axis of future spinal cord

Question 8

different concentration thresholds of SHH

Answer 8

results in cells producing different transcription factors

Question 9

early stages with SHH

Answer 9

there are distinct bands to recognise the different progenitor domains