DLL4, also known as delta-like protein 4, is involved in the Notch signaling pathway as Notch ligand. Therefore it negatively regulates endothelial cell proliferation and migration and angiogenic sprouting. Essential for retinal progenitor proliferation is required for suppressing rod fates in late retinal progenitors as well as for proper generation of other retinal cell types. During spinal cord neurogenesis, it inhibits V2a interneuron fate. Recombinant mouse DLL4, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.