Beta-1,3-N-Acetylglucosaminyltransferase 4 (b3GNT4)

B3GNT4 is a 378-amino acid type II transmembrane protein that contains an N-terminal cytoplasmic domain of either 29 or 4 residues due to the presence of 2 initiation codons; a 20-residue transmembrane segment; and a 329-residue stem region and catalytic domain with 3 potential N-linked glycosylation sites. FLAG-fused B3GNT4 was expressed as an approximately 38- to 40-kD glycoprotein. B3GNT4 is a beta-1,3-N acetylglucosaminyltransferase with a preferred substrate of lacto-N-neotetraose, and that it is involved in the biosynthesis of poly-N-acetyllactosamine sugar chains. RT-PCR analysis detected expression mainly in brain, including hippocampus, amygdala, cerebellum, and caudate nucleus, as well as in colon, esophagus, and kidney; expression was not detected in colon cancer, lymphoma, or promyelocytic leukemia cell lines.