Figure 4

Identification and characterization of survivin core promoter region. (A) Relative luciferase activity of different survivin promoter constructs (5′-deletion and 3′-deletion) in KG-1a-LCSs and non-LSC subpopulations. The cells were transfected with 1 μg of promoter plasmid along with 50 ng of β-actin-Renilla luciferase plasmid as control. (B) The core promoter region of survivin was identified (-218 to +170), and several transcription factor binding sites were predicted using Mat-Inspector and Jaspar (underlined regions). The arrow denotes the start site of survivin transcription, and the initiation codon ATG is shown in bold and italicized font. (C) Mutation of each transcription factor binding site was performed for identification of potential trans-activation motifs. Luciferase assays showed changes in promoter region activity for the mutants versus wild-type construct (^* P < 0.05; ^** P < 0.01). (D) Mutant E and mutant H are c-Myc and Sp1 binding sites, respectively; the sequences of the two motifs are shown. All graphs represent at least triplicate independent experiments.