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Kidney Int. 1997 Feb;51(2):564-6.

The hypoxia-inducible factor-1 DNA recognition site is cAMP-responsive.

Author information

1
Institute of Physiology, University of Z├╝rich-Irchel, Switzerland.

Abstract

The hypoxia-inducible factor-1 (HIF-1) was first described as a DNA binding activity that specifically recognizes an 8 bp hypoxia response element (HRE) known to be essential for oxygen-regulated erythropoietin gene expression. In electrophoretic mobility shift assays (EMSAs) HIF-1 DNA binding activity is only detectable in nuclear extracts of cells cultivated in a low oxygen atmosphere. In addition to HIF-1, a constitutive DNA binding activity also specifically binds the HIF-1 probe. Based on EMSAs using competitor oligonucleotides, specific antibodies and recombinant proteins, we previously reported that the constitutive HRE binding factor is composed of ATF-1 and CREB-1. Here we show that this site is functionally responsive to the cAMP agonist 8Br-cAMP in a dose-dependent manner under hypoxic but not under normoxic conditions. These results were confirmed by using the protein kinase A (PKA) activator Sp-cAMPS and the PKA inhibitor Rp-cAMPS: while Sp-cAMPS was synergistic with hypoxia on the HIF-1 DNA recognition site, the Rp-cAMPS isomer showed no effect. Our findings suggest that the PKA-signaling pathway is enhancing oxygen-dependent gene expression via the HRE.

PMID:
9027740
DOI:
10.1038/ki.1997.80
[Indexed for MEDLINE]
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