SMC3 and MED12 depletion significantly reduces the estrogen-induced expression of ERα target genes. MCF7 cells transfected with control, SMC3 or MED12 siRNA were grown in normal growth medium for 24 h and then for another 42 h in hormone-depleted medium before treating with 10 nM 17β-Estradiol (E2) for 6 h as indicated. Total mRNA was extracted, reverse-transcribed and analyzed by quantitative real-time PCR (qRT-PCR). (A) The expression levels of the estrogen-regulated genes CXCL12, GREB1, PGR, and PKIB were normalized to 28S ribosomal mRNA, graphed relative to the control sample and expressed as relative mRNA expression; mean values + SD, n = 4. (B) Efficient knockdown of MED12 and SMC3 was verified by qRT-PCR in the same samples used in (A). MED12 and SMC3 were normalized and expressed as in (A). Mean values + SD, n = 4.