Figure 2

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Figure 2. Mechanisms of neural induction in Xenopus embryos. (A) Ectodermal cells of the animal pole of gastrula-stage Xenopus embryos are subject to tonic BMP4-mediated signaling (red arrows), which promotes their differentiation into epidermal cells. Blockade of BMP4 signaling elicits the formation of anterior neural plate tissue. Exposure of ectoderm to FGFs under conditions in which BMP4 signaling is reduced or eliminated leads to the generation of posterior neural plate tissue. (B) A potential mechanism of action of anterior neural inducers derived from prospective axial mesoderm (the organizer region). Chordin, noggin, and follistatin are each secreted by organizer cells and induce neural tissue by blocking BMP4-mediated signaling between ectodermal cells. RI and RII, BMP receptor subunits. (C) Both noggin and chordin bind to BMP4. Follistatin can bind to BMP7 and possibly also to other BMPs.

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Science, Vol 274, Issue 5290, 1115-1123 , 15 November 1996 [HELP with high resolution image viewing] [Return to Article]
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