Activation of hypoxia-induced transcription in normoxia

Journal Article · Sun May 15 04:00:00 EDT 2005 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2005.01.017· OSTI ID:20717604

Haegg, Maria ^[1]; Wennstroem, Stefan ^[1]

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1. Department of Genetics and Pathology, Rudbeck Laboratory, Dag Hammarskjoelds vaeg 20, S-751 85 Uppsala (Sweden)

Hypoxia-inducible factor-1 (HIF-1), the master regulator of transcriptional responses to reduced oxygen tension (hypoxia) in mammalian cells, consists of one HIF-1{alpha} and one HIF-1{beta} subunit. In normoxia, HIF-1{alpha} subunits are hydroxylated on specific proline residues; modifications that signal ubiquitination and degradation of HIF-1{alpha} by the proteasome. To test the effect of saturating HIF-1{alpha} degradation, we generated a construct, denoted the saturating domain (SD), based on a region surrounding proline 564 (Pro564) in HIF-1{alpha}. Expression of the SD led to accumulation of endogenous HIF-1{alpha} proteins in nuclei of normoxic cells. The induced HIF-1{alpha} was functional as it activated expression from a hypoxia-regulated reporter gene and from the endogenous vascular endothelial growth facor-a (Vegf-a) and carbonic anhydrase 9 (Ca9) genes. The effect of the SD was dependent on Pro564 since a mutated SD, in which Pro564 had been replaced by a glycine residue, failed to bind the von Hippel-Lindau protein (pVHL) and to stabilise HIF-1{alpha}. Treatment of cells with the prolylhydroxylase inhibitor dimethyloxalylglycine, or the proteasome inhibitor MG-132, mimicked the effect of the SD. In conclusion, we show that blocking HIF-1{alpha} degradation, either by saturation, or inhibition of prolyl hydroxylases or proteosomal degradation, leads to nuclear localisation of active HIF-1{alpha} proteins.

• OSTI ID: 20717604
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 1 Vol. 306; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANOXIA
CARBONIC ANHYDRASE
GLYCINE
GROWTH
GROWTH FACTORS
HYDROXYLASES
INHIBITION
PROLINE
TRANSCRIPTION