Fig. 1.

Structure of the three NR1I2 mRNA transcripts (PXR.1, PXR.2, PXR.3) and binding sites of the respective primer pairs. Exons 2 through 9 are represented as gray rectangles, the alternative exon 1 (1a or 1b) is shown in white. The region of exon 5 that is only expressed in PXR.1 and PXR.2 is highlighted in black. The primer pair for total NR1I2 (NR1I2-for; NR1I2-rev; gray arrows) binds to exon 8/9 (forward primer) and 9 (reverse primer). Primer pair combinations only for NR1I2 splice variants bind to regions being selectively present in the respective transcript variant. PXR.1-for recognizes PXR.1 and PXR.3; PXR.1-rev recognizes PXR.1 and PXR.2; PXR2-for recognizes only PXR.2; PXR.2-rev recognizes PXR.1-3; PXR.3-for recognizes only PXR.3; PXR.3-rev recognizes PXR1-3. The combination of PXR.1-for/rev, PXR.2-for/rev, and PXR.3-for/rev is thus selective for only one splice variant