FIGURE 4. The effect of the IκBSR on enterocyte apoptosis. A, Changes in NF-κB sequence-specific binding activity in IEC-6 cells exposed to TCDCA in the presence of the IκBSR or control vector. Representative autoradiograms from nuclear extracts in control cells and cells 6 hours after exposure to 0.5 mmol/L TDCA. EMSA was performed as described above. Positions of the specifically bound DNA-protein binding complex are indicated. B, The effect of the IκBSR on TNF-α/CHX induced apoptosis in the presence of 0.5 mmol/L TDCA. IEC-6 cells transfected with the IκBSR were grown in the presence and absence of 0.5 mmol/L TDCA for 6 days. Apoptosis was induced using TNF-α/CHX as described above. Displayed on the y-axis is the percentage of apoptotic cells. *P < 0.01 versus control. **P < 0.01 versus TCDCA.