Figure 4

PBX3 is a Let-7d target gene. A) A schematic presentation of the 3'UTR sequence of PBX3 included in the reporter plasmids. The mature Let-7d sequence is shown underneath and the predicted Let-7d binding region is underlined. The underlined nucleotides are deleted in the pMIR-Luc-PBX3-3'UTR-Mut plasmid. B) LNCaP cells transiently transfected with either empty vector (pMIR-Luc) or reporter plasmids containing the 3'UTR-PBX3 in either the correct (pMIR-Luc-PBX3 3'UTR) or the inverse orientation (pMIR-Luc-PBX3 3'UTR-Rev) were harvested and reporter activity measured. C) Reporter plasmids containing the 3'UTR of PBX3 with either the wild-type binding site of Let-7d present (pMIR-Luc-Pbx3 3'UTR marked PBX3 3'UTR) or deleted (PBX3 3'UTRmut) were transfected into LNCaP cells in the absence or presence of 5·10^-8 M Let-7d mimic. The cells were harvested 48 hours post-transfection. Luciferase activity adjusted for β-galactosidase activity is shown in the histograms. Data are presented as mean ± SD (n = 3) relative to LNCaP cells transfected with PBX3 3'UTR. A t-test (paired two samples of mean) was performed and a two-tailed p-value < 0, 05 is indicated with a *.