miR-29b targets Sp1. (A) Genomic representation of the Sp1 3′ UTR with the localization of the 4 predicted pre-miR-29b binding sites. Immediately below there is a schema of the luciferase reporter assays used in the luciferase experiments. The “X” sign over the red boxes indicates the miR-29b sites that were deleted. mut indicates mutated. (B) Dual luciferase assay of K562 cells cotransfected with firefly luciferase constructs containing the wild-type or mutants target site of the Sp1 3′ UTR region with pre-miR-29b or a scrambled oligonucleotide. The data are shown as relative luciferase activity of pre-miR-29b-transfected cells with respect to the control (scrambled oligonucleotide) of 9 experiments from 3 independent transfections. Bars represent SD. (C) Sp1 mRNA and protein expression after nucleoporation (K562, MV4-11) or infection (Kasumi-1) of pre-miR-29b or their respective controls, scrambled oligonucleotide, or empty vector lentivirus. Histograms show fold changes with SD. (D) Sp1 mRNA expression in 3 primary AML samples after nucleoporation of pre-miR-29b or scrambled oligonucleotide. Histograms show fold change (reduction) with respect to control after normalization with 18s. Bars represent SD.