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#ventral cells

2 public questions tagged with this topic.

frog development

Dominant negative GSK3 expression in ventral cells results in:

Glycogen synthase kinase-3 normally phosphorylates beta-catenin at N-terminal residues targeting it for beta-TrCP mediated ubiquitination in ventral cells. Dominant-negative GSK3 carries mutation abolishing kinase activity but retains binding to Axin complex, competitively blocking endogenous enzyme. When expressed on ventral side, it allows beta-catenin stabilization, nuclear entry, activation of Siamois and Twin and formation of ectopic Nieuwkoop center. Ectopic center induces secondary Spemann organizer ventrally that organizes host tissues into complete secondary embryonic axis with indepe

Ref: Heasman et al., Wnt signaling and GSK3 in Xenopus axis, Development Journal, Axis duplication mechanism.

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frog development

Noggin injection in ventral cells of Xenopus embryos mimics:

In normal gastrula, dorsal blastopore lip secretes noggin that antagonizes BMP signaling creating low BMP zone permitting dorsal mesoderm and neural ectoderm formation. Ventral marginal zone normally receives high BMP specifying ventral mesoderm and epidermis. Ectopic noggin mRNA injected ventrally diffuses extracellularly binding BMPs and preventing receptor engagement, generating BMP-free niche ventrally. Neighboring cells respond by expressing organizer genes and self-organizing into second axis with notochord, somites and neural tube. This phenocopies Spemann graft proving single BMP antag

Ref: Smith and Harland, Noggin and neural induction, Cell 1989, Organizer mimicry by BMP inhibition.

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