FIG. 5.

PML-RARα associates with pRB. (A) Coimmunoprecipitation of pRB and PML-RARα was performed as described in Materials and Methods, using the lysate from a U937 clone expressing PML-RARα (PR9) (see the legend to Fig. 2 for abbreviations). Left, Western blot analysis of anti-PML (PG-M3) and anti-pRB (XZ77) immunoprecipitates with the anti-RARα anti-F antibody; right, Western blot analysis with the anti-pRB antibody G3-245. (B) PML-RARα mutants bearing deletions analogous to those described for PML in Fig. 3 within the PML moiety of PML-RARα (ΔC-PR and ΔH-PR [30]) were assayed for the capacity to bind pRB. Coimmunoprecipitation experiments were performed with lysates from U937 cell clones expressing the indicated PML-RARα mutants.