FXR binds to the LRH-1 responsive element in the <i>hSHP</i> promoter.

FXR was precipitated from nuclear extracts of hFXR-overexpressing DLD-1 cells using a DNA probe containing the SHP −122/−69 region (“wild type”(WT) or “mutated”(mut)), the IR-1 from the hBSEP promoter (positive control), the LacI binding site (negative control) or empty beads (EB, negative control). A) DNA probes of SHP −122/−69 and BSEP-IR-1 bind FXR. Competition experiments were performed with 3-fold excess hBSEP-IR-1 or LacI lacking a biotin label. B) the SHP −122/−69 region with a mutated LRH-1 site failed to precipitate or compete for FXR binding. Competition experiments were performed with 3-fold excess wild type SHP −122/−69, mutated SHP −122/−69 or LacI lacking a biotin label.本实验从过表达人源法尼醇X受体（hFXR）的DLD-1细胞的细胞核提取物中，分别使用以下试剂亲和沉淀富集FXR：含有SHP −122/−69区域（"野生型（WT）"或"突变型（mut）"）的DNA探针、人BSEP启动子的IR-1元件（阳性对照）、LacI结合位点（阴性对照），以及空白磁珠（EB，阴性对照）。 A) SHP −122/−69与BSEP-IR-1的DNA探针可与FXR结合。本实验通过加入3倍过量的未标记生物素的hBSEP-IR-1或LacI开展竞争实验。 B) 携带LRH-1位点突变的SHP −122/−69区域无法沉淀FXR，也无法竞争结合FXR。本实验通过加入3倍过量的野生型SHP −122/−69、突变型SHP −122/−69或未标记生物素的LacI开展竞争实验。