Figure 1.

Luciferase assay of hTERT promoter activity in RCC23 and RCC23+3. A series of hTERT promoter fragments (nucleotide positions follow Horikawa et al., 1999) were cloned upstream of the firefly luciferase reporter gene in the pGL3-Basic vector. Schematic representation of transcription factor binding sites is shown at top (ER, estrogen receptor; Misiti et al., 2000; see text for the others). The firefly luciferase activity was normalized with the Renilla reniformis luciferase activity by the cotransfected pRL-SV40. The mean and SD from at least three independent experiments are shown. For each construct, the activity in RCC23 was divided by that in RCC23+3 to determine the ratio of RCC23/RCC23+3 as an indicator of chromosome 3–mediated fold repression, shown at right.