Figure 5.

Antiestrogen induction of GstYa-GH reporter activity is mediated by an EpRE. 231 cells were transfected with an expression vector for the ER along with (A) pGstYa-GH reporter construct (missing the 41-bp EpRE-containing fragment), (B) TREX2-GstYa-GH reporter construct, or (C) mutated p41–284GstYa-GH reporter constructs. The nucleotide sequence of the 41-bp EpRE-containing fragment. The consensus EpRE, ETS binding site, and GCA box are also indicated. The mutated nucleotides are indicated by the boxed regions in mutants 1–5. The cells were also transfected with the β-gal internal reporter to correct for transfection efficiency. They were then treated with TOT (10⁻⁷ M) or TBHQ (10⁻⁵ M) for 48 hr. Media were collected for measurement of GH levels and the cells were then harvested for measurement of β-gal activity as described. Values are the means ± SE from three separate experiments.