The PML-retinoic acid receptor alpha (RARA) oncoprotein, which is generated by the translocation, blocks the differentiation, and ATRA is thought to modulate the dominant negative function of PML-RARA.     ///    PML-RARA transcripts were not down-regulated by ATRA.     ///    Accelerated degradation of PML-retinoic acid receptor alpha (PML-RARA) oncoprotein by all-trans-retinoic acid in acute promyelocytic leukemia: possible role of the proteasome pathway..     ///    "In this study, we showed by means of immunoblotting that the expression of PML-RARA decreased within 12 h in APL cells treated with ATRA at concentrations greater than 0.1 microM. "    ///    "These data indicate that the PML-RARA degradation is accelerated by pharmacological concentrations of ATRA, suggesting that ATRA allows APL cells to differentiate by relieving the differentiation block.. "    ///    "However, the molecular effect of ATRA on PML-RARA is unknown. "    ///    The decrease of PML-RARA was associated with restoration of the normal subcellular PML localization.     ///    "However, lactacystin, a specific inhibitor of the proteasome, almost completely inhibited the decrease of PML-RARA. "