Skip to main content
. 2016 Apr 21;291(24):12688–12705. doi: 10.1074/jbc.M116.714147

FIGURE 1.

FIGURE 1.

Transcription factor HBP1 promotes p21 transcription, probably by regulating the expression of p53 and EZH2. A, HBP1 and p21 are down-regulated at the mRNA level in lung adenocarcinoma according to bioinformatics analysis. In the rank-based gene expression curves, the x axis represents expressional intensity reflected by rank scores, whereas the y axis indicates sample percentiles at each rank score. B, HBP1 overexpression increases p53 and p21 expression and decreases EZH2 expression. The protein levels of HBP1, p53, p21, Mdm2, and EZH2 were measured by Western blotting in A549, HepG2, or U2OS cells stably transfected with PITA or PITA-HA-HBP1 through lentiviral infection. GAPDH was used as a loading control (left panel). The mRNA levels of p53, p21, Mdm2, and EZH2 were measured by real-time PCR in A549 cells stably transfected with PITA or PITA-HA-HBP1 through lentiviral infection. Results are representative of three independent experiments, and values are the mean ± S.E. *, p < 0.05. C, HBP1 knockdown by shRNA decreases p53 and p21 expression and increases EZH2 expression. The protein levels of HBP1, p53, p21, Mdm2, and EZH2 were measured by Western blotting in A549, HepG2, or U2OS cells stably transfected with pLL3.7-shHBP1 or pLL3.7 (as a control) through lentiviral infection. GAPDH was used as a loading control (left panel). The mRNA levels of p53, p21, Mdm2, and EZH2 were measured by real-time PCR in A549 cells transfected with pLL3.7-shHBP1 or pLL3.7. Results are representative of three independent experiments, and values are the mean ± S.E. *, p < 0.05. D and E, HBP1 enhances p53 protein expression at the posttranscriptional level. The protein levels of HBP1, p53, p21, and EZH2 were measured by Western blotting in H1299 cells cotransfected with HA-tagged p53 and GFP with or without HBP1 transfection (D). The protein levels of HBP1, p53, p21, and EZH2 were measured by Western blotting in H1299 cells cotransfected with HA-tagged p53 and GFP with or without HBP1shRNA transfection (E). The level of GFP is shown as equal transfection efficiency.