Specific Expression of a Myeloid-associated CMP-NeuAc:Galβ1→3GalNAcα-R α2→3-Sialyltransferase and the Sialyl-X Determinant in Myeloid Human-Mouse Cell Hybrids Containing Human Chromosome 11

Abstract Human-murine myeloid somatic cell hybrids were assayed for the expression of the myeloid-associated sialyl-X determinant. This determinant is expressed at the surface of hybrid cells containing human chromosome 11, but its expression could not be correlated with the presence of the sialyltransferase which is involved in the sialyl-X synthesis. The sialyl-X determinant, however, is simultaneously expressed with another α2→3-sialytransferase activity, which is involved in the sialylation of the O -linked Galβ1→3GalNAcα-R core structure. Chromosomal analyses and enzymatic data suggest that human chromosome 11 is involved in the expression of both the sialyl-X antigen and this α2→3-sialyltransferase.