Figure 1. Estrogen response element (ERE) mediated promoter activity in U251 glial cell line.

The addition of 10^-10M estradiol for 2 and 8 h to U251 cell co-transfected with the 3xERE reporter construct and the ERα expression plasmid resulted in an approximate 17-fold and 7.5-fold induction of the 3xERE promoter activity, respectively **p<0.0001, compared to NT, ERβ alone, and ERα/ERβ together; n=8 for all groups). Independent one-way ANOVAs for the ERβ and ERα and β transfected groups revealed that the 2 and 8 h treatments of estradiol significantly increased the promoter activity over their respective controls albeit to a lesser degree than ERα (^†p<0.0006 and ^††p<0.0001). Estradiol treatment did not induce ER activity in the U251 cell not transfected with ER expression plasmids (NT). Basal expression of the pGL3-Enhancer vector was unchanged in all groups (data not shown). Data are the mean± SEM.