Recognition of MAREs located in the TXAS gene by the BACH1 factor. (A) RT-PCR analysis of TXAS, BACH1, and p45 mRNA in UT-7/EPO and UT-7/TPO cells. The TXAS gene was expressed in UT-7/TPO, whereas the TXAS gene was detected only marginally in UT-7/EPO. Input RNA levels were normalized using G3PDH transcripts as controls. To ensure linearity of the PCRs, 10-fold serial dilutions of template cDNA were used. PCR products were electrophoresed using Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA) and DNA1000 LabChip (Agilent Technologies) kits. (B) Schematic representation of the human TXAS gene. The regions amplified by the ChIP assay were shown to be nfe2-1, nfe2-3, and exon 13. The nfe2-1 and nfe2-3 sites contain the MARE, which has been implicated in TXAS gene expression. (C) ChIP analysis using an anti-Bach antibody (A1-5) in UT-7/EPO and UT-7/TPO. Gel images show PCR products corresponding to nfe2-1, nfe2-3, and exon 13, obtained using input (lanes 1 and 4) and precipitated chromatin as templates (lanes 2, 3, 5, and 6). The exon 13 template DNA was used as a control. Fragments containing MARE located in the second intron (nfe2-1) or in their proximal promoter (nfe2-3) were precipitated by an anti-Bach1 antibody in UT-7/EPO (lane 3) or in UT-7/TPO (lane 6). Normal mouse IgG was used as a control (lanes 2 and 5). These results represent 4 independent experiments.