FIG. 5.

Identification of a CBE in the cyclin B1 core promoter. Shown is the cotransfection of increasing amounts of CIF150 expression plasmid (1 and 2 μg) with cyclin B1 wild-type (wt) and cyclin B1 promoter mutant constructs fused to a luciferase reporter plasmid. The amount of CMV-derived vector in each transfection assay was kept constant by using an unrelated expression plasmid (pEVRF1-Ob). The values shown are the averages of four independent experiments ± standard deviations (error bars). An arrow indicates the transcription start site, and the −25 region of the promoter is underlined. Bold nucleotides indicate the changes in the mutated promoter constructs.