Interaction of acute-phase-inducible and liver-enriched nuclear factors with the promoter region of the mouse alpha 1-acid glycoprotein gene-1.
The synthesis and secretion of several acute-phase proteins increases markedly following physiological stress. alpha 1-Acid glycoprotein (AGP), a major acute-phase reactant made by the liver, is strongly induced by inflammatory agents such as lipopolysaccharide (LPS). Nuclear run-on assay showed a 17-fold increase in the rate of AGP transcription 4 h following LPS injection. DNase I footprinting assays revealed multiple protein binding domains in the mouse AGP-1 promoter region. Region B (-104 to -91) is protected by a liver-enriched transcription factor that is heat labile and in limiting quantity. An adjacent region, C (-125 to -104), is well-protected by nuclear extracts from hepatocytes. Electrophoretic mobility shift assays indicated that only one DNA-protein complex can form with an oligonucleotide corresponding to region B. However, nuclear proteins from untreated mouse liver can form three strong complexes (C1, C2, and C3) and a weak one (C4) with oligonucleotide C. An acute-phase-inducible DNA-binding protein (AP-DBP) forms complex 4. A dramatic increase (over 11-fold) in AP-DBP binding activity is seen with nuclear proteins from LPS-stimulated animals. Interestingly, AP-DBP, a heat-stable factor, can form heterodimers with the transcription factor CCAAT/enhancer binding protein (C/EBP). Furthermore, purified C/EBP also binds avidly to region C. Our studies indicate that several liver-enriched nuclear factors can interact with AGP-1 promoter and that AP-DBP binds to the AGP-1 promoter with high affinity only during the acute-phase induction.
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch.
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Alam
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Papaconstantinou
D000210:Acute-Phase Reaction / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002467:Cell Nucleus / Q000378:metabolism*; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D004247:DNA / Q000235:genetics; D016172:DNA Fingerprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D009961:Orosomucoid / Q000096:biosynthesis / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012313:RNA / Q000032:analysis; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009961:Orosomucoid; D014157:Transcription Factors; D012313:RNA; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase