Fig. 4
E2-induced binding of the ERα onto the PIWIL1 promoter by estrogen. a A Schematic representation of the half-ERE in the PIWIL1 promoter and the three pairs of primers used for ChIP-qPCR was shown. TSS: transcription start sites. b the PIWIL1 promoter region was precipitated by the antibody against ERα in Ishikawa cells cultured in normal media. IgG served as the negative control. RT-qPCR was performed on ChIP samples. *p < 0.05, **p < 0.01 and ns, not significant versus control group. c Ishikawa cells treated with 10− 8 mol/L E2 for 0, 45, and 135 min were subjected to ChIP and the precipitated DNA was analyzed by RT-qPCR. Experimental conditions are identical to those in panel b, except that cells were cultured in hormone-free media for 72 h before E2 treatment. All experiments were performed at three times. *p < 0.05, ***p < 0.001 and ****p < 0.0001 versus control group (cells without E2 treatment). d the effects of PIWIL on E2-induced cell growth were determined by MTT assay. *p < 0.05 and **p < 0.01 versus control group