Figure 4.

Effect of Tax on the ERα complex binding to ERE and BRCA1 promoter. MCF-7 cells which were or not transfected with 1.5 μg of Tax variants [w.t.Tax, TaxM22, TaxM47 or Tax(V89A)] as indicated in the figure. The cells were treated with E2 at 5 hr before their extraction for examining the binding of the appropriate proteins to BRCA1 promoter (A) or ERE region (B and C) by CHIP assay as described in Materials and Methods section. Control cells were not transfected with Tax and not treated with E2. The presented results are an average of 3 repeated experiments ± SE.