Neural cells arise unexpectedly from the endoderm

摘要

The nervous systems of all embryos are thought to arise from the ectoderm-one of the three germ layers from which all organs and tissues develop. However, Zheng Wei et al. (pp. 9143-9147) show that in sea urchins, at least some of the neurons in the pharynx arise from the foregut endoderm. Although the sea urchin endoderm is defined by a well-characterized gene regulatory network, this tissue can generate neurons when primed with expression from the right genes, including the essential transcription factors, Six3 and Nkx3-2.