FIGURE 4.

Deletion and mutation analysis of putative Sp1 binding sites in the hCSE core promoter. A, the 5′ deletion constructs of the hCSE core promoter regions were schematically shown on the left panels. Nucleotides of fusion plasmids were numbered with respect to the transcriptional start site. Firefly luciferase activities were divided by the activities of Renilla luciferase and expressed as relative activity divided by the promoter-less construct (PGL3-Basic). B, mutation for Sp1 binding sites diminished the hCSE promoter activity. The mutated sequences were shown in boldface type. The data in A and B were from four independent experiments in duplicate. *, p < 0.05.