gastrulation in xenopus and zebrafishIII Flashcards
What are the ectoderm and endoderm specified by?
Maternal determinants in the egg
What is the maternal determinant of ectoderm?
Ectodermin
What is the maternal determinant of the enoderm?
VegT
WHat can VegT do alongside inducing endoderm specification?
Induces nodal signal expression
What do nodal signals d to cells in the animal region?
Instruct them to become mesoderm
Where is Foxl1e expressed?
ANimal pole
Role of Foxl1e?
Instructs animal cells to be ectoderm
Role of ectodermin?
Inhibits nodal signals–> prevents all the cells from becoming mesoderm
What are the zygotic determinants of mesoderm?
Nodals
Where is the organizer formed?
Dorsal side of the mesoderm
Result of VegT and B-Catenin converging?
High nodal levels
Where do B-Catenin and VegT converge?
Organizer–> dorsal region of mesoderm
Nodal signalling gradient?
Dorsal ventral, w/ the highest being in the dorsal side
Which proteins are used to establish the organizer?
B-catenin and nodal
WHat is brachyury?
One of the first markers detected for mesoderm fate
Which TFs are expressed in the organizer region?
goosecoid, not, lim1
What does goosecoid determine?
Dorsal mesoderm
What can brachyury upregulate?
FGF signalling
FGF brachyury loop?
Brachyury upregulates FGF, which feeds back onto brachyury
Maintains mesodermal identity
Where is BMP signalling present?
Whole embryo except organizer region
where is Wnt 8 expressed?
Mesoderm except organizer region
Early Wnt signalling?
Highest in dorsal region, lowest in ventral side
Early Wnt target genes?
Nodal related proteins, Dkk1, cerebus, noggin chordin
Role of Dkk1 and cerebus?
Inhibition of Wnt signalling at organizing centre
