Probable O-linked N-acetylglucosamine transferase (OGT) involved in various processes such as gibberellin (GA) signaling pathway. OGTs catalyze the addition of nucleotide-activated sugars directly onto the polypeptide through O-glycosidic linkage with the hydroxyl of serine or threonine. Probably acts by adding O-linked sugars to yet unknown proteins. L-seryl-[protein] + UDP-N-acetyl-alpha-D-glucosamine = 3-O-(N-acetyl-beta-D-glucosaminyl)-L-seryl-[protein] + H(+) + UDP L-threonyl-[protein] + UDP-N-acetyl-alpha-D-glucosamine = 3-O-(N-acetyl-beta-D-glucosaminyl)-L-threonyl-[protein] + H(+) + UDP Protein modification; protein glycosylation. Expressed in stems, leaves and flowers. Expressed during all stages of corolla maturation. Not up-regulated by GA3 or ABA application. The TPR repeats mediate protein-protein interactions. Expression of such repeats in plants generate a dominant-negative mutant. Belongs to the glycosyltransferase 41 family. O-GlcNAc transferase subfamily.