HUMAN N-ACETYLGLUCOSAMINE-6-O-SULFOTRANSFERASE INVOLVED IN THE BIOSYNTHESIS OF 6-SULFO SIALYL-LEWIS-X - MOLECULAR-CLONING, CHROMOSOMAL MAPPING, AND EXPRESSION IN VARIOUS ORGANS AND TUMOR-CELLS

N-Acetylglucosamine-6-O-sulfotransferase catalyzes the transfer of sul fate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of a non -reducing N-acetylglucosamine (GlcNAc) residue. We have cloned human G lcNAc-6-O-sulfotransferase cDNA, based on the sequence homology to clo ned cDNA of mouse GlcNAc-6-O-sulfotransferase. The predicted protein s equence of the human enzyme was highly homologous to that of the mouse enzyme; in the 363 amino acid stretch of the catalytic region, the tw o proteins were nearly identical except for conservative changes in 3 amino acid residues. The expressed enzyme transferred sulfate to GlcNA c beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4GlcNAc. Co-transfecti on of the enzyme cDNA and fucosyltransferase VII cDNA into COS-7 cells resulted in cell surface expression of 6-sulfo sialyl Lewis X. Fluore scence irt situ hybridization analysis revealed that the GlcNAc-6-O-su lfotransferase gene is located on human chromosome 7q31. mRNA of the h uman enzyme was strongly expressed in the bone marrow, peripheral bloo d leukocytes, spleen, brain, spinal cord, ovary, and placenta, and mod erate levels of expression were observed in many organs including lymp h nodes and thymus. In situ hybridization with the mouse system showed that the transcript was localized in specific regions of the brain, i .e. pyramidal cells in the CA3 subregion of the hippocampus, cerebella r nucleus and Purkinje cells. Among human tumor cells, strong expressi on of the mRNA was found in MOLT-4 and Jarkat lymphoblastic leukemia c ells, Raji lymphoma cells, K-562 chronic myelogeneous leukemia cells, U251 glioma cells, and G361 melanoma cells. Carbohydrate structures sy nthesized by the sulfotransferase may be involved in various aspects o f the differentiation and behavior of blood cells, their progenitor ce lls, and neurons in the central nervous system.