Fig. 5.

Digoxigenin (DIG) nonradioactive gel shift assay showed direct binding of CDX2 to the DRA promoter. Synthetic oligonucleotides containing the 2 putative CDX2 binding sites (Fig. 4A) were used. A: +645/+663 site showed direct binding of DIG-labeled probe with nuclear extract (lane 2). This interaction was increased with ectopic overexpression of CDX2 (lane 5). In both cases, CDX2 binding was attenuated when competed with a 200-fold excess of cold oligonucleotide (lanes 3 and 4) or when mutated probe was used (lane 6). B: probes containing −360/−378 (−) binding site did not show an interaction between CDX2 and DRA. Blot is representative of 3 independent experiments.