Comparison of Akt1 and Akt3 for their abilities to activate the Fra-1 promoter. Comparison of Akt1 and Akt3 for their abilities to activate the Fra-1 promoter. MCF-7 cells were transiently transfected with a Fra-1 promoter-reporter construct (pFra4), the control Renilla luciferase plasmid, and the indicated amounts of plasmids encoding either constitutively active Akt1 (Akt1) or constitutively active Akt3 (Akt3). In each case, the total amount of cDNA transfected was kept constant by adding the empty plasmid pcDNA3.1. Forty-eight hours after transfection, the cells were lysed and luciferase activities measured. Results shown are the means ± SE of three independent experiments where the amount of firefly luciferase activity was normalized to the amount of Renilla luciferase activity measured in each sample. The lower panel shows the amounts of expressed Akt in the different transfected samples as detected in Western blots. Gunjan Tiwari et al. Mol Cancer Res 2003;1:475-484 ©2003 by American Association for Cancer Research