Bone morphogenetic protein signaling is required in the dorsal neural folds before neurulation for the induction of spinal neural crest cells and dorsal neurons.

Bone Morphogenetic Protein (BMP) activity has been implicated as a key regulator of multiple aspects of dorsal neural tube development. BMP signaling in the dorsal-most neuroepithelial cells presumably plays a critical role. We use tissue-specific gene ablation to probe the roles of BMPR1A, the type 1 BMP receptor that is seemingly the best candidate to mediate the activities of BMPs on early dorsal neural development. We use two different Cre lines expressed in the dorsal neural folds, one prior to spinal neurulation and one shortly afterward, together with a Bmpr1a conditional null mutation. Our findings indicate that BMPR1A signaling in the dorsal neural folds is important for hindbrain neural tube closure, but suggest it is dispensable for spinal neurulation. Our results also demonstrate a requirement for BMP signaling in patterning of dorsal neural tube cell fate and in neural crest cell formation, and imply a critical period shortly before neural tube closure.