retinoic acid receptor signaling pathway involved in somitogenesis

Definition

Target type: biologicalprocess

The series of molecular signals generated as a consequence of a retinoic acid receptor binding to one of its physiological ligands that contributes to somitogenesis. [GOC:ascb_2009, GOC:dph, GOC:tb]

Retinoic acid (RA), a derivative of vitamin A, plays a critical role in somitogenesis, the process of forming somites, the building blocks of the vertebral column, ribs, and skeletal muscles. RA signaling is mediated by retinoic acid receptors (RARs), nuclear receptors that bind to specific DNA sequences known as retinoic acid response elements (RAREs). The RARs form heterodimers with retinoid X receptors (RXRs), which are also nuclear receptors.

The expression of RA and its receptors is precisely regulated during somitogenesis. RA is produced in a gradient along the anterior-posterior axis of the embryo, with higher concentrations in the anterior region. This gradient is established by the coordinated expression of enzymes involved in RA synthesis and degradation.

RA signaling influences somitogenesis through several mechanisms. First, RA acts as a morphogen, meaning that its concentration determines the fate of cells. Cells exposed to high levels of RA are committed to anterior fates, while cells exposed to low levels of RA adopt posterior fates. This gradient of RA activity contributes to the sequential formation of somites along the anterior-posterior axis.

Second, RA regulates the expression of key genes involved in somitogenesis, including the Notch signaling pathway. The Notch pathway is essential for the segmentation of the presomitic mesoderm, the tissue from which somites are formed. RA activates Notch signaling in the presomitic mesoderm, promoting the formation of somitomere boundaries.

Third, RA influences the expression of genes involved in the differentiation of somite cells. Somites differentiate into various cell types, including skeletal muscle, cartilage, and dermis. RA promotes the expression of genes associated with muscle differentiation, while inhibiting the expression of genes associated with cartilage differentiation.

Overall, RA signaling is an intricate and precisely regulated process that plays a crucial role in somitogenesis. The gradient of RA activity, the regulation of key genes, and the influence on cell fate determination all contribute to the formation of well-defined somites along the anterior-posterior axis of the developing embryo.'
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Proteins (1)

Compounds (4)