Fig. 2.

The expression of human and mouse ABCA1, and of mouse ABCG1 are regulated by miR-33. (A–C) Evolutionary conserved sequences in the 3′ UTR of ABCA1 and ABCG1 are partially complementary to miR-33. Annealings of miR-33 to some of the sequences are shown. (D) Luciferase activity in HEK293 cells after cotransfection of different constructs containing these putative response elements for miR-33 cloned downstream of the reporter stop codon, cotransfected with or without a miR-33 expression plasmid. Repression of luciferase activity suggests that these sequences are physiological targets for miR-33. Deviation from miR-33 complementarity results in loss of regulation by miR-33 (ABCA1 box 2; human ABCG1 sequence). (E) Expression of selected genes in Hep3B human hepatoma cells 48 h after transduction with an empty or a miR-33 adenovirus. (F) ABCA1 protein levels also are decreased after transduction of Hep3B cells with the miR-33 adenovirus. Where indicated, cells were incubated for 16 h with LXR:RXR agonists [1 μmol/L T0901317 (T) and 1 μmol/L 9-cis retinoid acid (9cRA)]. **P < 0.01. Data are mean ± SD of three independent experiments in duplicate.