Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2013 Apr 5;288(20):14451–14462. doi: 10.1074/jbc.M113.460840

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2013 by The American Society for Biochemistry and Molecular Biology, Inc.

PMC Copyright notice

FIGURE 4. — The C/EBPβ-HDAC1 complex represses the p53 promoter. A, location of C/EBP sites within the p53 promoter and diagram of the mutant constructs. luc, luciferase. B, EMSA with the probe covering C/EBP binding site 1 within the p53 promoter. The probe was incubated with nuclear extracts (NE) from livers of DEN-treated mice. Antibodies (shown at the top) were added to the binding reactions. Note that Abs to C/EBPβ neutralize the binding. SS, supershift; free, free probe; NS, nonspecific band. C, mutation of C/EBP sites reduces the basal activity of the p53 promoter and the ability of C/EBPβ to activate the p53 promoter. The luciferase constructs (shown in A) were cotransfected with C/EBPβ into Hep3B2 cells, and the luciferase activity was calculated. V, vector; A–E, constructs shown in A. *, p < 0.05. D, the C/EBPβ-HDAC1 complex inhibits the p53 promoter. The luciferase construct containing the 1.6-kb p53 promoter was cotransfected with different amounts of C/EBPβ and HDAC1. Luciferase activity was determined (bar graphs). The top panel shows levels of C/EBPβ in experimental cells determined by Western blotting. E, knockdown of endogenous HDAC1 activates the p53 promoter and increases the ability of C/EBPβ to activate the p53 promoter. Endogenous HDAC1 was inhibited by siRNA in cells transfected with the p53-luc constructs and in cells transfected with the p53-luc construct and C/EBPβ. The bottom panel shows levels of HDAC1 after inhibition by siRNA. F, knockdown of endogenous C/EBPβ reduces the ability of HDAC1 to repress the p53 promoter. The experiments were performed as described above. The bottom panel shows inhibition of C/EBPβ by siRNA. G, C/EBPβ-HDAC1 complexes repress the p53 promoter in DEN-treated mice. A ChIP assay was performed with chromatin solutions from control (DEN 0) and DEN-treated mice (DEN 20 and DEN 35). Ag, negative control; AcK9 and MeK9 immunoprecipitations with Abs to histone H3 acetylated at Lys-9 and trimethylated at Lys-9, respectively. H, diagram summarizing the effects of CUGBP1 and the C/EBPβ-HDAC1 complex on the p53 promoter.