Figure 3. cis-element EGR-1/Sp1 constitutes a PMA-response motif.

(A) The nucleotide sequence of the hNHE3 promoter region from bp −95 to +5 is shown and the location of the potential cis-elements is indicated. (B) 5′-Deletion constructs harbouring further deletion in the NHE3 proximal promoter region were transiently transfected into C2BBe1 cells, as indicated in the legend to Figure 2, and were similarly either treated with PMA or not treated. After 48 h, the cell lysates were prepared and luciferase activities were determined. Luciferase activity was corrected for transfection efficiency using β-galactosidase activity and presented relative to the normalized activity of the pGL2-Basic vector. Results are presented as the means±S.E.M. (n=3). *, Significantly different from the p−88/+5 treated with PMA, P<0.05.