Delta Like Protein 4 (dLL4)

DLL4 is a homolog of the Drosophila delta gene. The delta gene family encodes Notch ligands that are characterized by a DSL domain, EGF repeats, and a transmembrane domain.

The predicted 685-amino acid DLL4 protein exhibits all of the hallmarks of the Delta family of Notch ligands. It has an extracellular region containing 8 EGF-like repeats and a DSL domain involved in Notch binding, as well as a transmembrane domain and a cytoplasmic tail that lacks catalytic motifs. Human DLL4 shares 87% amino acid sequence identity with mouse Dll4. Northern blot analysis of mouse tissues detected highest Dll4 expression in lung, followed by heart, kidney, skeletal muscle, and brain; Dll4 expression was barely detectable in spleen and testis.