10. Vertebrate Gastrulation II Flashcards
(39 cards)
What is the focus of the lecture?
The molecular mechanisms that induce the organizer and drive gastrulation.
Define polarity in the context of embryonic development.
Animal-vegetal axis in the egg (morphological feature).
What is symmetry breaking?
Sperm entry induces cortical rotation, establishing dorsal-ventral axis.
What information is present in the egg before fertilization?
Information for three germ layers.
Where is VegT localized?
In the vegetal pole.
What is the function of VegT?
A transcription factor that regulates Nodal.
What type of ligand is Nodal?
TGF-β family ligand.
What role does Nodal play in embryonic development?
Mediates cell-cell communication and helps specify mesoderm.
What is Veg1?
Another factor in the vegetal pole that is translated into a TGF-β ligand.
What is the TGF-β signaling pathway?
Involves specific receptors that become phosphorylated and activate Smad proteins.
What does the fate map at the late blastula stage indicate for prospective ectoderm?
Animal pole.
What does the fate map at the late blastula stage indicate for prospective mesoderm?
Middle region.
What does the fate map at the late blastula stage indicate for prospective endoderm?
Vegetal pole.
Who discovered the organizer?
Hilde Mangold and Hans Spemann in 1924.
What is the original name of the organizer?
Spemann organizer.
List the four main functions of the organizer.
- Self-differentiation into dorsal mesoderm
- Dorsalizes surrounding mesoderm
- Induces neural plate and neural tube in ectoderm
- Acts as the site of gastrulation movements.
What happens during early transplantation of presumptive neural ectoderm?
It adopts host fate (epidermis).
What is demonstrated by late transplantation of the same tissue?
Maintains neural identity when transplanted.
What was the result of transplanting the dorsal blastopore lip?
Created secondary body axis with neural tube, notochord, somites.
What significant discovery was made regarding the human organizer in 2018?
Scientists created primitive streak using human iPSCs and generated secondary axis.
Who discovered the Nieuwkoop Center?
Peter Nieuwkoop.
What is formed in the Nieuwkoop Center?
Coincidence of VegT, Veg1, and β-catenin in dorsal region.
What is the function of the Nieuwkoop Center?
Acts as the signaling center that induces the organizer.
What occurs during cortical rotation after fertilization?
Dishevelled protein moves from vegetal pole to future dorsal side.
