Figure 6

Plasmid constructs and CAT activity in transfected SaOS-2 cells. PCR products from the IGFBP-6 gene promoter were inserted upstream from the luciferase gene in the promoterless pCAT-Basic vector. The putative transcription activation sites are indicated as ERE-1 and ERE-2 in a schematic representation of the constructs (above panel). These constructs were cotransfected with the ERα expression vector into SaOS-2 cells. The transfected cells were then treated with E2 (1 µM) for 24 h. Cellular extracts were prepared and the β-gal and CAT activities were then determined. The CAT activity was normalized to β-gal units and is presented as fold of vehicle control. CAT activities are expressed as the mean ± SEM for three separate determinations in each treatment group. Statistical significance of differences between groups was determined. ^*indicates a significant difference between the ERE construct and the control group.