c-Myc required functional Sp1 binding sites to activate survivin transcription. (A) c-Myc and Sp1 mutant constructs used for this study. (B) The effects of mutation of Sp1, c-Myc,and combined mutation of the two motifs on the relative luciferase activity of the wild-type V5 promoter in KG-1a and MOLM13LSCs. The mutant and wild-type constructs were transfected along with Renilla luciferase plasmid as control (*
P < 0.05, **
P < 0.01). (C) The effects of c-Myc over-expression on survivin promoter activity in the context of mutated Sp1 binding sites. The mutant Sp1 site constructs were co-transfected with pcDNA-c-Myc or empty vector and Renilla luciferase plasmid. Luciferase assays were performed 48 h post-transfection. (D) The effects of Sp1 over-expression on survivin promoter activity in the context of mutated c-Myc binding sites. All transfection conditions were performed as previous described.