Abstract
Expression of many mammalian genes is regulated by oxygen tension. HIF-1 alpha and HLF/EPAS are two basic helix-loop-helix/PAS domain transcription factors that bind to hypoxia sensitive elements in the promoters /enhancers of hypoxia sensitive genes such as vascular endothelial growth factor (VEGF). This paper describes the structure of rat HIF-1 alpha and analyses expressions HIF-1 alpha and of HLF/EPAS mRNAs in lung and cardiac tissues from the rat. HLF/EPAS mRNAs appear at birth in the two tissues and are maintained at high levels throughout adult life. HIF-1 alpha mRNAs are expressed at a constant level during lung development. Their abundance increase transiently at birth in cardiac tissues. Cultured cardiomyocytes from new born rats only express HIF-1 alpha mRNAs. HIF-1 alpha mRNA expression is increased by phorbol myristate acetate but not by anoxia or cobalt. The results indicate (i) that HIF-1 alpha and HLF/EPAS are expressed in a cell specific manner and (ii) that the hypoxic induction of VEGF mRNA expression by isolated cardiomyocytes is independent of HLF/EPAS. Finally, they suggest that protein kinase C may prime hypoxia induced gene regulation by inducing expression of HIF-1 alpha mRNAs.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Basic-Leucine Zipper Transcription Factors
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Blotting, Northern
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Cells, Cultured
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DNA-Binding Proteins / biosynthesis
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics*
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Endothelial Growth Factors / genetics
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Endothelial Growth Factors / metabolism
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Gene Expression Regulation*
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Heart / embryology
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Heart / growth & development
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Helix-Loop-Helix Motifs / genetics*
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Hypoxia / genetics
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Hypoxia / metabolism*
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Hypoxia-Inducible Factor 1
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Hypoxia-Inducible Factor 1, alpha Subunit
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Lung / embryology
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Lung / growth & development
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Lung / metabolism
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Lymphokines / genetics
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Lymphokines / metabolism
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Molecular Sequence Data
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Myocardium / metabolism*
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Nuclear Proteins / biosynthesis
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Rats
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Sequence Analysis, DNA
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Tetradecanoylphorbol Acetate / pharmacology
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Transcription Factors / biosynthesis
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Transcription Factors / chemistry
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Transcription Factors / genetics*
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
Substances
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Basic-Leucine Zipper Transcription Factors
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DNA-Binding Proteins
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Endothelial Growth Factors
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Hif1a protein, rat
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Hypoxia-Inducible Factor 1
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Hypoxia-Inducible Factor 1, alpha Subunit
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Lymphokines
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Nuclear Proteins
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RNA, Messenger
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Transcription Factors
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Vascular Endothelial Growth Factor A
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Vascular Endothelial Growth Factors
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Hlf protein, rat
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Tetradecanoylphorbol Acetate