Function
GATL1 is essential for the biosynthesis of the tetrasaccharide primer sequence, beta-D-Xyl-(1,3)-alpha-l-Rha-(1,2)-alpha-D-GalA-(1,4)-D-Xyl, located at the reducing end of glucuronoxylan. This enzyme likely catalyzes the transfer of the reducing Xyl residue onto a protein acceptor in the endoplasmic reticulum. This protein-bound tetrasaccharide is subsequently transported to the Golgi apparatus where the remaining sugar residues are added to complete the biosynthesis of glucuronoxylan.