Hypoxia regulates expression of the endothelin-1 gene through a proximal hypoxia-inducible factor-1 binding site on the antisense strand.
Endothelin-1 (ET-1) is a peptide hormone with potent vasoconstrictor properties that is synthesized and secreted predominantly by vascular endothelial cells. Its production is regulated by numerous stimuli including ischemia and hypoxia, and the enhanced levels that occur during myocardial ischemia may contribute to the progression of heart failure. We previously reported that ET-1 expression was induced by both hypoxia and transition metals in endothelial cells (ECs). Here we define an element in the proximal promoter of the ET-1 gene that is responsible for this induction. By using deletions and site directed mutagenesis of the human ET-1 promoter, in combination with electrophoretic gel mobility shifts and transient expression assays in human ECs, we identified an active hypoxia-inducible factor 1 (HIF-1) binding site starting at position -118 upstream of the transcription start site on the non-coding DNA strand. Mutation of this site eliminated induction by hypoxia without affecting basal (aerobic) expression, and the mutated sequence did not display hypoxia-specific binding of HIF-1.
Hu
J
J
Department of Molecular and Cellular Pharmacology, University of Miami Medical Center, Florida 33136, USA.
Discher
D J
DJ
Bishopric
N H
NH
Webster
K A
KA
D001665:Binding Sites; D015687:Cell Hypoxia; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019332:Endothelin-1 / Q000235:genetics*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000378:metabolism*; D010100:Oxygen / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D019332:Endothelin-1; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; D014157:Transcription Factors; D010100:Oxygen