Glycosyltransferase that generates the core 1 O-glycan Gal-beta1-3GalNAc-alpha1-Ser/Thr (T antigen), which is a precursor for many extended O-glycans in glycoproteins (PubMed:11677243). Plays a central role in many processes, such as angiogenesis, thrombopoiesis and kidney homeostasis development (By similarity).
