Glycosyltransferase that initiates the elongation of O-linked fucose residues attached to EGF-like repeats in the extracellular domain of Notch molecules. Modulates NOTCH1 activity by modifying O-fucose residues at specific EGF-like domains resulting in enhancement of NOTCH1 activation by DLL1 and JAG1. May be involved in limb formation and in neurogenesis.
