Neuralization of the Xenopus embryo by inhibition of p300/ CREB-binding protein function.

p300/ CREB-binding protein (CBP) is a transcriptional coactivator for a plethora of transcription factors and plays critical roles in signal transduction pathways. We report that the inhibition of p300/CBP function in the Xenopus embryo abolishes non-neural tissue formation and, strikingly, initiates neural induction and primary neurogenesis in the entire embryo. The observed neuralization is achieved in the absence of anterior or posterior gene expression, suggesting that neural fate activation and anterior patterning may represent distinct molecular events. We further demonstrate that the neuralizing and anteriorizing activities of chordin and noggin are separable properties of these neural inducers. This study reveals that all embryonic cells possess intrinsic neuralizing capability and that p300/CBP function is essential for embryonic germ layer formation and neural fate suppression during vertebrate embryogenesis.