dorsal/ventral neural tube patterning

Definition

Target type: biologicalprocess

The process in which the neural tube is regionalized in the dorsoventral axis. [GO_REF:0000021, GOC:cls, GOC:dgh, GOC:dph, GOC:jid, PMID:11262869]

The dorsal/ventral patterning of the neural tube is a complex and precisely orchestrated process that establishes the distinct identities of the various neuronal populations within the central nervous system. This process is driven by a series of inductive signals emanating from surrounding tissues, which activate transcription factors that ultimately control the expression of genes specific to different neuronal subtypes.

The formation of the neural tube itself begins with the folding of the neural plate, a sheet of ectodermal cells along the dorsal midline of the embryo. As the neural plate folds, it forms a hollow tube that detaches from the ectoderm. This neural tube will eventually give rise to the brain and spinal cord.

The establishment of dorsal-ventral identity within the neural tube is initiated by signals from the notochord, a rod-shaped structure that lies beneath the neural tube. The notochord secretes the protein Sonic hedgehog (Shh), which acts as a morphogen, a signaling molecule that diffuses from its source and creates a concentration gradient across the neural tube. Cells located closest to the notochord experience the highest Shh concentration, while cells further away receive progressively lower concentrations.

This Shh gradient establishes a precise pattern of gene expression along the dorsal-ventral axis of the neural tube. Cells at the ventral midline, exposed to the highest levels of Shh, are induced to express genes that specify a floor plate identity, which gives rise to specialized neuronal subtypes responsible for motor functions.

As Shh levels decrease further from the midline, a series of transcription factors are sequentially activated, creating a cascade of gene expression that defines progressively more dorsal neuronal fates. These include motor neuron progenitors, interneurons, and ultimately dorsal sensory neurons.

Concurrently, signals from the dorsal ectoderm, specifically from a structure called the roof plate, induce expression of BMPs (bone morphogenetic proteins). BMPs act as antagonists to Shh signaling, establishing a second gradient along the dorsal-ventral axis.

The interplay between Shh and BMP signaling ultimately defines the specific neuronal subtypes that develop at each position within the neural tube. This intricate interplay of inductive signals and transcription factor activation ensures the precise patterning of the neural tube, laying the foundation for the development of a functional nervous system.'
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Proteins (5)

Compounds (45)