RID-α modulates sterol-regulated gene expression. (a) Transcriptional mechanisms controlling expression of the target genes LDLR, HMGR, and CYP7B described in Results. (b–d) LDLR (b), HMGR (c), and CYP7B (d) mRNA levels quantified by real-time PCR. Values are expressed as relative units after internal normalization to glyceraldehyde 3-phosphate dehydrogenase mRNA levels and compared with control samples from the same cell lines cultured in 10% FBS from three independent experiments. Data are presented as mean ± SEM (*, P < 0.001).