RARE binding by homodimers of APL fusion proteins.

Binding of homodimers of STAT5b-RARα (A), PML-RARα (B), and PLZF-RARα (C) and heterodimers of RARα/RXRα (D) to a series of RAREs. Gel-shift assays were performed with in vitro translated proteins using the following radiolabeled probes: synthetic RARE, DR1, 2, 3, 4 and 5G,40 β₂ RARE (DR5T) from the human RARB gene,30 α₂ RARE from the human RARA gene,59 the natural enhancer elements from the rat cellular retinal-binding protein type I gene (CRBPI),60 the rat cellular retinal-binding protein type II gene (CRBPII),61 the murine cellular RA-binding protein gene (CRABPII),62,HOXA1 gene,63,HOXB1gene64 and p21-WAF1gene.65 Equivalent amounts of in vitro translated protein and labeled oligonucleotide were added to each binding reaction. The results of quantitative analysis using ImageQuant software are shown below each autoradiogram. In panel E, radiolabeled DR5G was incubated with in vitro translated STAT5b-RARα and the indicated fold excess unlabeled DR5G followed by gel-shift assay.