Alterations in Glycosyltransferase Levels in Mouse Erythroleukemia Cells during Erythrodifferentiation and Cell Growth1

Mouse erythroleukemia (MEL) cells contained galactosyltransferase (GT), fucosyltransferase (FT), and A/-acetylglucosaminyltransferase activities and only a small amount of sialyltransferase activity. Dimethyl sulfoxide-treated MEL cells, un dergoing erythrodifferentiation, contained twice as much GT, 20 to 50% less FT, and approximately the same amount of Nacetylglucosaminyltransferase activities as did untreated cells. When log-phase MEL cells were used as the starting culture, GT activity remained constant during log phase but decreased to 30 to 60% of the log-phase level as the cells reached stationary phase. Under these conditions, FT activity increased more than two-fold as the cells reached stationary phase. When stationary-phase MEL cells were used as the starting culture, GT activity increased as the cells entered log phase and decreased as the cells returned to stationary phase. FT activity decreased initially and then increased as the cells reached stationary phase. Whether log-phase or stationary-phase MEL cells were used as the starting culture, cells maintained in dimethyl sulfoxide always contained more GT and less FT activity than did untreated cells. Since the changes in GT and FT activities were dependent on the concentration of dimethyl sulfoxide used and occurred prior to the onset of hemoglobin synthesis, it is possible that they are related to erythrodiffer entiation in MEL cells.