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. 2008 Nov 7;283(45):31079–31086. doi: 10.1074/jbc.M806041200

FIGURE 3.

FIGURE 3.

miR-221 and miR-222 interact with the conserved site of the ERα 3′-UTR. A, pmiR-ERα1 but not pmiR-ERα2 reporter activity is reduced only in miR-221/222-positive MDA-MB-468 cells. The pmiR-ERα1-Luc and pmiR-ERα2-Luc plasmids were introduced into MCF-7 and MDA-MB-468 cells together with β-galactosidase. Luciferase activity was measured and normalized after a 36-h incubation. B, ectopic expression of miR-221 or miR-222 inhibits pmiR-ERα1-Luc and pmiR-ERα1-3-Luc but not seed sequence mutant pmiR-ERα1-5-Luc. MCF-7 cells were transfected with the indicated plasmids and assayed for luciferase activity after a 36-h incubation. The inset shows expression of transfected miR-221 and miR-222. M stands for marker. snRNA, small nuclear RNA. C and D, the activities of pmiR-ERα1-Luc and pmiR-ERα1-3-Luc but not seed sequence mutant pmiR-ERα1-5-Luc are reduced in MDA-MB-468 cells (C), which are partially abrogated by knockdown of miR-221/222 (D). MDA-MB-468 cells were transfected with the indicated plasmids and 2′-O-Me. Following a 36-h incubation, luciferase reporter assay was performed as described under “Experimental Procedures.” All experiments were repeated three times in triplicate. Expression of miR-221 and miR-222 is shown in the inset.