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Vg1 role
- Member of the TGF-B family
- the ONLY TgF-B protein that is localized DORSALLY
- Needed for ANTERIOR development!
- Located in VEGETAL Cytoplasm, which is where formation of mesoderm occurs
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Paper results related to Vg1 role
- Although Vg1 overexpression does not cause mesoderm formation, LOSS of Vg1 causes loss in mesoderm formation and DELAYED GASTRULATION
- An allele made with Serine residue is able to rescue effects of Vg1 loss of function, better than inserting the original Vg1 transcript.
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Vg1 and signalling
- 1. Vg1 signaling NEEDED for phosphorylation of SMAD2
- 2. Vg1 signaling NEEDED to PREVENT Bmp signaling by phosphorylation of Smad1
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Vg1 results Fig 1
- Showed that through stages of gastrulation, Vg1 depleted
- Vg1 has NO affect on Xnr3 or siamois, which are required for Wny pathway activation, so Vg1 NOT needed for Wnt pathway
- Mesoderm inducing signals chordin and cerebus REDUCED at mid-gastrula stages,
- Mesoderm markers cerebus, chordin, noggin and signals FGF8 and Xbra are DOWNREGULATED with Vg1 Depletion
- Vg1 depleted showed UPREGULATION of Bmp target gene Sizzled, but No change w BMP4
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Vg1 results Fig 2
- changing amino acid Vg1(ser) showed HIGHER expression vs Proline
- Serine able to rescue partially the Vg1 depleted affect, by increasing Smad2 protein back to WT levels
- Vg1(S) rescued partially mesoderm markers cerebus, chordin, noggin and dkk
- Vg1(S) rescued mesoderm signals FGF8, Xnr1, chordin and Xsox17a during gastrulation stages
- Vg1(S) rescued Bmp target Sizzled, brought the levels back down (were up with depletion)
- Vg1 seen at HIGHER proportion DORSALLY via Realtime and Western (when compared to ventral, with VegT as control for all over cell)
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