N-Acetylglucosamine-6-O-sulfotransferase catalyzes the transfer of
sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of a non-reducing
N-acetylglucosamine (GlcNAc) residue. We have cloned human
GlcNAc-6-O-sulfotransferase cDNA, based on the sequence homology to cloned
cDNA of mouse
GlcNAc-6-O-sulfotransferase. The predicted
protein sequence of the human
enzyme was highly homologous to that of the mouse
enzyme; in the 363
amino acid stretch of the catalytic region, the two
proteins were nearly identical except for conservative changes in 3
amino acid residues. The expressed
enzyme transferred
sulfate to GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Gl cNAc. Co-transfection of the
enzyme cDNA and
fucosyltransferase VII
cDNA into COS-7 cells resulted in cell surface expression of
6-sulfo sialyl Lewis X. Fluorescence in situ hybridization analysis revealed that the
GlcNAc-6-O-sulfotransferase gene is located on human chromosome 7q31.
mRNA of the human
enzyme was strongly expressed in the bone marrow, peripheral blood leukocytes, spleen, brain, spinal cord, ovary, and placenta, and moderate levels of expression were observed in many organs including lymph 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, cerebellar nucleus and Purkinje cells. Among human
tumor cells, strong expression of the
mRNA was found in MOLT-4 and Jarkat
lymphoblastic leukemia cells, Raji
lymphoma cells, K-562 chronic myelogeneous
leukemia cells, U251
glioma cells, and G361
melanoma cells.
Carbohydrate structures synthesized by the
sulfotransferase may be involved in various aspects of the differentiation and behavior of blood cells, their progenitor cells, and neurons in the central nervous system.