Figure 5. A GC-box mediates transcriptional activity of the 180 bp core promoter. (A) A3.01 T cells were transfected with reporter plasmid pGL3-Basic containing 180, 150 or 120 bp of the A3G promoter. The two G-to-T substitutions introduced into the GC-box of the 180 bp fragment (180mut) are specified. After 48 h, cells were harvested for luciferase assay. Firefly luciferase activities were normalized to coexpressed renilla luciferase activities. Mean values (±SD) of a representative experiment performed in triplicate are shown. (B) pGL3-Promoter reporter plasmids containing the regions E1 or E2 (see Figure 1) upstream of the SV40 promoter were transfected into A3.01 T cells. Firefly luciferase activities after 48 h were normalized to coexpressed renilla luciferase activities. Mean values (±SD) of a representative experiment performed in triplicate are shown.