Regulatory Effect of All-trans Retinoic Acid (ATRA) on the Activities of N-acetylglucosaminyl Transferase (GnT) III, IV in HL-60 Cells.

The regulatory effect of all-trans retinoic acid (ATRA) on the activities of N-acetylglucosaminyl transferase (GnT) III and IV in HL-60 Cells were studied. It was found that the activities of GnT-III and GnT-IV were significantly decreased by 0.1 &mgr;M ATRA, but not further decreased with the increase in concentration of ATRA to 1.0 or 10 &mgr;M. The activities of both GnT-III and GnT-IV in the untreated control cells were variable during the incubation of cells, showing a peak level at 24 h and 48 h in the un-synchronized culture and the synchronized culture respectively. After the treatment with ATRA, the peak value was still at 24h in un-synchronized culture, and the activities of GnT-III and GnT-IV were gradually decreased only after 24 h of incubation both in un- synchronized and synchronized culture of HL-60 cells. The above results were discussed.