Concerted participation of NF-kappa B and C/EBP heteromer in lipopolysaccharide induction of serum amyloid A gene expression in liver.
The promoter region of the rabbit serum amyloid A (SAA) gene contains two adjacent C/EBP and one NF-kappa B binding element. Involvement of these elements in SAA gene induction, following lipopolysaccharide (LPS) stimulation of the liver, has been studied by investigating LPS-activated transcription factors and their interaction with the promoter elements of the SAA gene. Appearance of complexes in the electrophoretic mobility shift assay has indicated that DNA-binding proteins that interact with the NF-kappa B element of the SAA promoter are induced in the LPS-treated rabbit liver. Presence of RelA (p65 subunit of NF-kappa B) in these complexes was demonstrated by the ability of RelA-specific antisera to supershift the DNA-protein complexes. LPS also induced several members of the C/EBP family of transcription factors, which interacted with the C/EBP motifs of the SAA promoter. Activated C/EBP and RelA form a RelA-C/EBP heteromeric complex that associates with varying affinity to NF-kappa B and C/EBP elements of the SAA gene. Transfection assays using both transcription factor genes have demonstrated that the heteromeric complex of NF-kappa B and C/EBP is a much more potent transactivator of SAA expression than each transcription factor alone. The heteromeric complex efficiently promotes transcription from both NF-kappa B and C/EBP sites.
Ray
A
A
Department of Veterinary Microbiology, University of Missouri, Columbia 65211, USA.
Hannink
M
M
Ray
B K
BK
D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D015345:Oligonucleotide Probes; D011401:Promoter Regions, Genetic; D011817:Rabbits; D000685:Serum Amyloid A Protein / Q000096:biosynthesis*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D016328:NF-kappa B; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D000685:Serum Amyloid A Protein; D014157:Transcription Factors