Wnt signaling pathway involved in somitogenesis

Definition

Target type: biologicalprocess

The series of molecular signals initiated by binding of Wnt protein to a frizzled family receptor on the surface of the target cell and ending with a change in cell state that contributes to somitogenesis. [GOC:ascb_2009, GOC:dph, GOC:tb]

Wnt signaling plays a crucial role in somitogenesis, the process of forming segmented blocks of mesoderm called somites. These somites will eventually give rise to muscles, vertebrae, and dermis. The process begins with the cyclic expression of genes that define segment boundaries, known as the segmentation clock. These genes, such as Hes7 and Lunatic fringe, oscillate in their expression levels in a synchronized manner throughout the presomitic mesoderm (PSM).

Wnt signaling is essential for maintaining the oscillatory expression of the segmentation clock genes. Wnt ligands, secreted signaling molecules, activate the canonical Wnt signaling pathway by binding to Frizzled receptors on the cell surface. This interaction leads to the stabilization of β-catenin, a key transcription factor that regulates the expression of target genes involved in somitogenesis.

The cyclical expression of the segmentation clock genes generates a temporal pattern that determines the location of somite boundaries. As the PSM elongates, the cells at the anterior end of the PSM reach a specific threshold of Wnt signaling, which triggers the formation of a new somite.

One of the critical targets of Wnt signaling in somitogenesis is the Tbx6 gene. Tbx6 is expressed in the PSM and is required for maintaining the undifferentiated state of PSM cells. Wnt signaling inhibits the expression of Tbx6, allowing for the formation of somites.

Another important aspect of Wnt signaling in somitogenesis is its role in regulating the expression of Notch signaling components. Wnt signaling promotes the expression of Delta-like ligand 1 (Dll1), a ligand for the Notch receptor. Notch signaling plays a crucial role in the formation of somite boundaries, promoting the expression of genes that define the anterior and posterior boundaries of each somite.

In summary, Wnt signaling is a key regulator of somitogenesis. It acts through multiple mechanisms to ensure the proper formation of somites, including maintaining the oscillatory expression of the segmentation clock genes, regulating the expression of Tbx6 and Notch signaling components. Disruption of Wnt signaling can lead to defects in somitogenesis, resulting in developmental abnormalities.'
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Proteins (2)

Compounds (2)