antibody staining (lecture 3, p.4). in situ hybridization (lecture 4 p.4)
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Antibody staining (Lecture 3, p.4)
In situ hybridization (Lecture 4 p.4)
mRNA depletion (“knockdown”) methods (Lecture 3, p.4)
-catenin
-catenin builds up
Axin
Wnt is absent. -catenin mRNA is continuouslytranslated and the protein is continuously degraded.
Wnt is present. -catenin protein is not degraded. It builds up, binds to Tcf/LEF and enters the nucleus.
Wnt11 protein
Outside cell
Inside cell
-cateninmRNA
Wnt, beta-catenin, and organizer formation
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Endo-mesoderm induction. Pieter Nieuwkoop 1968
(Nieuwkoop center)
(Nieuwkoop center)
Nodal signaling pathway(belongs to TGF-beta family of pathways)
phospho-Smad2
A dominant negative form of the Nodal (or Bmp)
receptor can block Nodal (or Bmp) signaling
Deplete and replace vegT mRNAvegT depletedNo mesoderm or endoderm,No blastopore
vegT mRNA restored by injection into vegetal hemisphere
vegT depleted and restored
VegT depleted embryos: rescue with mRNA for xnr1, 5, 6, or derriere, injected into vegetal pole cells
Normal late blastula:xnr1 expressed in vegetal cells
derriere rescue
xnr5, xnr6 rescue
xnr1 rescue
xnr1