FIGURE 4.

Fli-I binding to ER and to the SWI/SNF complex is important for ER-mediated transcription. A and B, autonomous activation function in the G1 motif of Fli-I. CV-1 cells were transfected with pGK1-luc reporter plasmid (200 ng) controlled by Gal4-responsive elements and expression plasmids encoding Gal4 DBD or Gal4 DBD fused to each gelsolin-like motif (G1 through G6) or to the E585K mutant of the G1 fragment (200 ng). Transfected cells were grown for 2 days and harvested for luciferase assays (bar graphs) and immunoblots using antibodies against Gal4 (upper panel of B). C, SW13 cells were transfected with murine mammary tumor virus-estrogen response element (MMTV-ERE) luciferase reporter plasmid (200 ng) and expression plasmids encoding ERα (0.1 ng), BRG1 (10 ng or 50 ng), and GelA, GelA(E585K) or GelA(LL/AA) (100 ng) as indicated. Transfected cells were grown with E2 for 48 h, and luciferase activities of the transfected-cell extracts were determined by luminometer (bar graph). Expression of wild type (wt) and mutant GelA was monitored by immunoblot using antibodies against the FLAG epitope (inset). RLU, relative luciferase units.