Figure 4

KLF1 drives expression from the Pu.2 ORR1A0 promoter. (A, B) SL2 cells were co-transfected with pGL4.10 Firefly luciferase reporter (promoter-less or containing the ORR1A0 promoter) together with increasing amounts of pPac-Klf1 (A) or a steady amount of pPac-Klf1 and increasing dosage of pPac-Klf3 (B). Firefly levels have been normalized to Renilla luciferase and in each instance the lowest value has been set to 1.0. Charts represent the mean of triplicate experiments and error bars show standard error of the mean. *, P <0.005 (Student’s two-tailed t-test) compared to pGL4.10-ORR1A0 wells transfected with 0 ng pPac-Klf1 (A) or 0 ng pPac-Klf3 (B). (C-E) KLF1-ER activity was induced in B1.6 cells by addition of tamoxifen and total RNA was extracted after 48 h and analyzed by quantitative real-time RT-PCR. Transcripts containing exons 2b/3 are increased (C) while those containing exons 2/3 are decreased (D). The total pool of Pu.1 plus Pu.2 mRNA is represented by exons 3/4 (E). Values have been normalized to 18S rRNA and in each case, the lowest value has been set to 1.0. Error bars represent standard error of the mean and n = 4 for each condition. **, P <0.05 (Student’s paired two-tailed t-test) compared to untreated cells.