Journal: International Journal of Molecular Sciences
Article Title: Hepatocyte Nuclear Factor 4α (HNF4α) Plays a Controlling Role in Expression of the Retinoic Acid Receptor β ( RARβ ) Gene in Hepatocytes
doi: 10.3390/ijms24108608
Figure Lengend Snippet: Mutation of the critical residues present in the ligand binding domain of human HNF4α suppresses transcription activation of the promoters of human APOC3 and CYP2C9 genes. HepG2 cells were co-transfected with either the p GL3-b-hApoC3 ( A – C ) or p GL3-b-hCYP2C9 ( D – F ) promoter construct together with either hHNF4α, RARα/RXRα, or all three transcription factors, and then treated with either vehicle or 1 µM RA for 24 h, after which the cells were assayed for their luciferase activity. The effects of the individual mutant residues in the ligand binding domain of the human HNF4α compared with WT HNF4α on the promoter activity of APOC3 ( B ) or CYP2C9 ( E ) in HepG2 cells treated with either vehicle or 1 μM RA for 24 h. The endogenous HNF4α transcriptional activity toward APOC3 ( C ) and CYP2C9 ( F ) promoters was assessed in HepG2 cells with or without the addition of human HNF4α mutants. Data from each bar represent the mean of n = 3 wells ± SD. HNF4α mutant #’s are as follows: (1) S190K, (2) 191MK, (3) R221G, (4) L228K, (5) L229K, (6) R235G, (7) I347K, and (8) I355K.
Article Snippet: Construction of the plasmid vectors including p GL3-Basic-hCYP26A1-E4-luc (submitted to addgene.org), p GL3-Basic-hRARβp-luc (human RARβ2 promoter), p GL3-Basic-hCYP2C9p-luc, p cDNNA3.1-hRARα.hRXRα (submitted to addgene.org), and p cDNA3.1-hHNF4α were reported previously [ , , , , ].
Techniques: Mutagenesis, Ligand Binding Assay, Activation Assay, Transfection, Construct, Luciferase, Activity Assay