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. 1999 Dec 21;96(26):14807–14812. doi: 10.1073/pnas.96.26.14807

Figure 1.

Figure 1

(A) RA triggers PML/RARα and RARα down-regulation in NB4 cells by Western blot analysis. ΔPML/RARα is a cleavage product of the fusion, and * denotes a nonspecific protein sometimes detected with the RARα antibody. (B) Comparison of RARα agonists (trans-RA, AM580, 9-cis-RA, and TTNPB) or antagonists (Roche Molecular Biochemicals; RO-415253, RO-61–8431, and RO-40–8757) for their ability to modulate PML/RARα and RARα expression. NB4 cells were treated for 2 days with the various compounds; all were at a 10−6 M concentration. (C) Kinetics of PML/RARα down- regulation induced by AS (10−6 M). (D) Effect of protease inhibitors on a decrease in PML/RARα.. NB4 cells were treated as indicated for 8 h (allowing for the decrease in PML/RARα, but not RARα, expression). Note the presence of higher molecular weight species with AS and inhibitors, which could represent a PML/RARa-Pic1 modification adduct (◂). (E) PML/RARα is degraded by caspases through a specific site in PML. 35S-labeled in vitro translated PML/RARα (Upper) or PML (Lower) were incubated with recombinant caspase 1, 3, 4, 6, 7, or 8 for 4 h and analyzed by PAGE. (F) PML is a functional caspase target in vivo. CHO cells overexpressing PML were treated with z-VAD, etoposide (a DNA-damaging agent that activates caspases), or both for 24 h. PML is cleaved (◂) in a z-VAD-reversible manner.