FIGURE 9.

Induction of APL differentiation by ATRA and As₂O₃ treatment relieves the interaction of C/EBPβ and Daxx. A, NB4 cells were treated with 1 μm ATRA for 36 h or left untreated. Aliquots of crude protein extracts were immunoprecipitated with C/EBPβ-specific antiserum or an unrelated control antiserum. Precipitated proteins were separated by SDS-PAGE and the amount of precipitated C/EBPβ and co-precipitated Daxx was detected by Western blotting using C/EBPβ and Daxx-specific antibodies, respectively. Analyses of the crude protein extracts were used as input controls. The asterisk in the lower right panel marks the immunoglobulin heavy chain. B, NB4 cells were incubated with or without 1 mm of As₂O₃ for the indicated times. Subsequently, cells were analyzed by Western blotting with antibodies against Daxx, C/EBPβ, and β-actin.