A, mRNP-IP assay and qPCR for IDH1 of mRNAs bound to HuR protein, relative to IgG in HT1080 cells. Results were represented as means of three independent experiments ± SEM. B, Chromatograms show allelic ratios of wild type and mutant IDH1 by semi-quantitiative Sanger sequencing (overlapping red and blue peaks are circled) for HuR RNP-IP relative to IgG control. C, HT1080 cells were transfected with siRNAs against HuR (or control siRNA) and IDH1 mRNA expression was measured by qPCR (Top panel), Representative immunoblots are provided for HuR and IDH1 from HT1080 cell lysates 72 h following transfection with siRNA oligos. ***, p < 0.001. D, Chromatograms show allelic ratios of wild type and mutant IDH1 by semi-quantitiative Sanger sequencing (overlapping red and blue peaks are circled) after HuR silencing relative to si.CTRL. E, Representative qPCR analysis of HuR and IDH1 mRNA expression 48 h after transfection with si.CTRL or si.HuR in BT054 cells. (Top panel), Representative immunoblots for HuR, IDH1 and IDH1.R132H of BT054 cell lysates 72 h following transfection with siRNA oligos. ***, p < 0.001.