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#organizer

2 public questions tagged with this topic.

Regeneration -l

Which structure acts as an 'organizer' in hydra regeneration?

Hypostome forms dome-shaped apex of Hydra body column containing mouth opening surrounded by tentacle ring. Microsurgical transplantation of isolated hypostome into gastric column of host induces secondary body axis with new head and tentacles, demonstrating organizer activity reminiscent of Spemann-Mangold dorsal lip. Molecularly hypostome secretes Wnt3, maintains high beta-catenin signaling, and expresses BMP antagonists establishing local source that recruits surrounding tissue to head fate. Epidermis contributes differentiated epitheliomuscular cells, mesoglea provides extracellular matrix

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 19: Hypostome as organizer in Hydra regeneration and axis induction.

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frog development

Organizer's primary function during amphibian gastrulation:

Organizer at dorsal blastopore lip is signaling center and mechanical engine of amphibian gastrulation. Initial phase involves apical constriction forming bottle cells at blastopore, then involution of head and axial mesoderm around lip, convergent extension driven by Wnt-PCP, and epiboly of ectoderm toward vegetal pole. Organizer secretes BMP antagonists and expresses Brachyury and goosecoid coordinating these movements. Removal impairs blastopore formation and mesoderm internalization arrests. Thus primary function during gastrulation is initiating and orchestrating gastrulation movements ra

Ref: Wolpert, Principles of Development 5th ed., Chapter 4: Organizer and gastrulation movements in amphibians.

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