Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm

TLDR

Dorsal neural cell fate is regulated by Sonic hedgehog repression from the notochord and a contact‑dependent inductive signal from the epidermal ectoderm. BMP4 and BMP7 produced by the epidermal ectoderm, along with BMP4 and DSL1 expressed in dorsal neural tube cells, initiate dorsal differentiation at the neural plate stage via opposing BMP dorsalizing and SHH ventralizing signals.

Abstract

The cellular interactions that control the differentiation of dorsal cell types from neural progenitors have been examined in neural plate explants. Certain genes that are expressed in the dorsal neural tube are initially expressed uniformly within the neural plate and appear to achieve their dorsal restriction through a Sonic hedgehog (SHH)-mediated repressive signal from the notochord. The acquisition of definitive dorsal cell fates, however, requires a contact-dependent signal from the epidermal ectoderm. BMP4 and BMP7 are expressed in the epidermal ectoderm, and both proteins mimic its inductive activity. BMP4 and a related gene, DSL1, are subsequently expressed by cells in the dorsal neural tube. The differentiation of dorsal cell types, therefore, appears to be initiated at the neural plate stage and to involve the opponent activities of a BMP-mediated dorsalizing signal from the epidermal ectoderm and a SHH-mediated ventralizing signal from the notochord.