Fig. 3.

HBXIP stimulates PKM promoter through binding to the −779/−579 region. a, b Luciferase reporter gene assay of PKM promoter activity in MCF-7 (a) and MCF-7-HBXIP cells (b). The cells were transiently transfected with indicated plasmids or siRNA, respectively. Luciferase activities were measured after transfection for 24 h. c Activities of corresponding fragments of PKM promoter were examined by luciferase reporter gene assay in MCF-7 cells, respectively. The cells were transiently transfected with pcDNA or pcDNA-HBXIP along with indicated fragments of PKM promoter. d ChIP assay was performed to evaluate the interaction of HBXIP with the promoter region (−779/−579) of PKM in MCF-7 cells. The right panel was the quantitative data of enrichment in PKM promoter analyzed by real-time PCR and normalized against the input. An upstream region of PKM gene promoter (−1458/−1345) was used as a negative control. Statistically significant differences are indicated: *P < 0.05, **P < 0.01, ***P < 0.001; All experiments were repeated at least three times