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#neural induction

3 public questions tagged with this topic.

amphibian -ll

Organizer-derived factors (Noggin, Chordin) prevent ectodermal cells from becoming:

Dorsal ectoderm fate choice depends on BMP signaling levels. In presence of BMP2/4/7, ectoderm expresses epidermal keratin via Dlx3, AP2 and p63 activation downstream of phospho-Smad1. Organizer secreted Noggin, Chordin and Follistatin bind BMPs extracellularly preventing receptor activation, lowering Smad1 activity. This blocks epidermal differentiation program, allowing neural genes Sox2, Sox3 expression revealing default neural fate. Therefore organizer factors prevent epidermal lineage adoption, not mesodermal or endodermal. Mesodermal and endodermal fates require separate Nodal and VegT s

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 10: Organizer prevents epidermal fate via BMP antagonism.

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amphibian -ll

Organizer proteins allow neural induction by blocking:

Ectodermal competence to become epidermis requires active BMP4/BMP7 signaling through Alk3/6 receptors phosphorylating Smad1/5/8, inducing epidermal transcription factors Msx1 and epidermal keratin via Dlx and AP2. Organizer releases Noggin, Chordin, Follistatin and Cerberus that sequester BMPs extracellularly, preventing BMP receptor activation in dorsal ectoderm. Under BMP inhibition, Smad1 inactive, p63 suppressed, allowing neural genes Sox3, Sox2 expression. Thus neural induction occurs essentially by derepressing default neural fate through blocking BMP signaling. Addition of BMP converts

Ref: Wolpert, Principles of Development, 5th ed., Chapter 6: Neural induction via BMP inhibition by organizer proteins.

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frog development

Organizer-induced neural tissue formation involves inhibition of:

Ectodermal competence model proposes both neural and epidermal fates possible. BMP4 secreted ventrolaterally binds BMPR inducing Smad1/5/8 phosphorylation, activating epidermal genes like keratin and Xvent while repressing neural genes Sox2, Zic1 and FoxD5. Organizer secretes three BMP antagonists chordin, noggin and follistatin that bind BMPs extracellularly preventing signaling. BMP inhibition dorsalizes ectoderm allowing neural transcription factors to dominate, neural plate forms. FGF and Wnt modulation assist but central switch for neural induction is BMP inhibition demonstrated by neural

Ref: NCBI Bookshelf, Developmental Biology Gilbert: Neural induction - BMP inhibition by organizer signals.

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