Gastrulation in mammals and chick III Flashcards
How many cells make up the node, and what is its structure?
200, ciliated structure
What is the node equivalent of?
The organizer–> it is producing growth factors
Effect of putting the node in a developing avian embryo?
Can cause duplication of digits
What does heterotrophic grafting of the node to a posterolateral position lead to (put a second, GFP labelled node in)?
A second neural axis
When putting an ectopic node in, what genes are seen?
Brachyury expression as well as FGF8 in the ectopic position
How many organisers do mice have?
2
WHich organisms have one organiser?
Frog, chick, fish
What is responsible for creating the body axis in the mouse?
The node
What is responsible for the formation of anterior structures like the heart?
The Node and the anterior visceral endoderm
Where are Wnts and FGFs produced in the embryo?
Posterior part
Where are BMPs and Wnt antagonists being produced in the embryo?
Anterior part
Retinoic acid gradient?
High posterior, low anterior
Result of high FGF and Wnt?
a high expression of CDX1, CDX2, and CDX4 (all of which are DNA binding proteins)
Which CDX protein is expressed anteriorly?
CDX1
Which CDX protein is expressed in the middle??
CDX2
Which CDX protein is expressed posteriorly?
CDX4
What do CDX1, 2, 4 regulate?
Homeobox gene cluster–> Hox genes
What do Hox genes do?
Set up the anterior posterior patterning in the body
What is the ID of your vertebrate determined by?
Hox genes–> depends which hox gene is on at that axia lev
Result of knocking out FGF8?
No migration of cells–> mesoderm wont form
How is AP patterning regulated?
retinoic acid gradients and FGF8 regulate CDX genes, which regulate Hox genes
When (days) does gastrulation occur?
6.25-9.5
When is the AP axis patterned?
Just prior to the onset of gastrulation
When does lineage diversification occur?
After gastrulation
