Chapter 12 - Robust spatial patterning in development

Question 1

What is a morphogen gradient?

Answer 1

In a mass of cells a morohogen is a TF that induces some change. The morphogen is being pruced at one point in the cell mass, and the concentration changes (there is a gradient) throughout the tissue.

Question 2

What is the purpose of a morphogen gradient?

Answer 2

The gradient defines coordinates for cells so they can differentiate accordingly.

Question 3

How is 3D patterning solved?

Answer 3

breaking it into multiple 1D problems.

Question 4

What is the decay length of a morphogen?

Answer 4

lambda = sqrt(D (diffusion costant) / alpha (degredation)

Question 5

What is the idea behind the french flag model?

Answer 5

Cells have different fates depending on the level ofmorphgen they are exposed to. As we move away from the morphogen source, morphogen concentration changes and the fate of the cells in that region changes.

Question 6

In the simpler morphogen model when M_0 changes so does morphogen levels later - how do we circumwent this?

Answer 6

By having a nonlinear degredation term with respects to morphogen concentrations - degredation higher for higher concentrations.

Question 7

Name network motifs that can provide degredation feedback:

Answer 7

1) M -> R -> increases M degredation

2) M -| R that inhibits M degredation.