DLL3

The DLL3 gene provides instructions for making a protein that helps control (regulate) the Notch pathway, an important pathway in embryonic development. The Notch pathway plays a critical role in the development of vertebrae. Specifically, the DLL3 protein and the Notch pathway are involved in separating future vertebrae from one another during early development, a complex process called somite segmentation. Although the exact mechanism of somite segmentation is unclear, it appears to require the activity of several proteins in the Notch pathway, including the NOTCH1 protein, to be turned on and off in a specific pattern (oscillate).

The DLL3 protein regulates the activity of the NOTCH1 protein. The DLL3 protein attaches (binds) to the inactive NOTCH1 protein and isolates (sequesters) it or marks it to be broken down so that it cannot be activated.

spondylocostal dysostosis - caused by mutations in the DLL3 gene

More than 25 mutations in the DLL3 gene have been found to cause spondylocostal dysostosis type 1, the most common type of spondylocostal dysostosis. This condition is characterized by the abnormal development of bones in the spine and ribs. The known mutations in the DLL3 gene prevent the production of any protein or lead to the production of an abnormally short, nonfunctional protein. When the DLL3 protein is nonfunctional or absent, the NOTCH1 protein is abnormally active and does not oscillate, so somite segmentation does not occur properly. This results in the malformation and fusion of the bones of the spine and ribs seen in spondylocostal dysostosis type 1.