Figure 2.

Ski is localized in a protein complex binding to a DR5 RARE. Cell extracts prepared from Ski-transformed BM cells were analyzed by EMSA by using oligonucleotides that contained a DR5 RARE (lanes 1–6) or an IFP-53 GAS element (lanes 7–9). The DR5 RARE and IFP-53 GAS complexes were incubated with 0.5 μl of an anti-gag mAb [(anti-gag-Ski); MC IG-10 ascites, prediluted to 1/10, lanes 2 and 8], 1 μl of a rabbit antiserum that was reactive with chicken STAT5b (anti-STAT5b, prediluted to 1/10, lanes 3 and 9), and 2 μl of antibodies to RARα and RXRα (lanes 5 and 6) as described. The arrows indicate the positions of the mobility-shifted complexes; the arrowheads indicate the positions of the DR5 RARE (Left) and IFP-53 GAS (Right) complexes that were supershifted by the anti-gag-Ski antibody and anti-STAT5 antibody, respectively.