Effects of c-jun expression on the transcriptional activation of CD164 promoter. (A) SW480 and HCT116 cells were transiently co-transfected with the pGL3P4 (0.8 μg/μl) and pCMV-c-jun (0.8 μg/μl), luciferase activity of cell lysates was measured and normalized to renilla activity as internal co ntrol (left). Results represented the mean ± SD of three independent experiments. Exogenous c-jun significantly enhanced the CD164 expression, *p < 0.01, Student's t-test. The Real-time PCR were performed to investigate the upregulated expression CD164 at mRNA level in HCT116 (right). (B) Mutational analysis of AP-1-like sites on CD164 promoter fragment P4. Schematic representation of the pGL3P4 regions containing AP-1-like binding sequence and its mutants. pGL3P4, a wild-type construct containing 258 bps of the 5'-flanking sequence upstream of TSS; P4AP-1 Amu, a mutated pGL3P4 plasmid containing a mutated AP-1-like motif (CGCTG TCCC) at -119; P4AP-1 Bmu, a mutated pGL3P4 plasmid containing a mutated AP-1-like motif (GTCTG TTG) at -54; P4AP-1 Both mu, a mutated pGL3P4 plasmid containing two mutated AP-1-like motifs (CGCTG TCCC,GTCTG TTG) at both of -119 and -54. pGL3P4 and its mutants were transfected in HCT 116 cells respectively and assayed for luciferase activity The relative activities of wild-type P4 and AP-1-like mutated P4 mutants were normalized with renilla expression. P4AP-1 Amu and P4AP-1 Both mu resulted in significant decreases in luciferase activity when compared to pGL3P4, whereas no significant change of luciferase activity was observed in P4AP-1 Bmu.