Activation of hypoxia-induced transcription in normoxia
2005 (English)In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 306, no 1, 180-191 p.Article in journal (Refereed) Published
Hypoxia-inducible factor-1 (HIF-1), the master regulator of transcriptional responses to reduced oxygen tension (hypoxia) in mammalian cells, consists of one HIF-1alpha and one HIF-1beta subunit. In normoxia, HIF-1alpha subunits are hydroxylated on specific proline residues; modifications that signal ubiquitination and degradation of HIF-1alpha by the proteasome. To test the effect of saturating HIF-1alpha degradation, we generated a construct, denoted the saturating domain (SD), based on a region surrounding proline 564 (Pro564) in HIF-1alpha. Expression of the SD led to accumulation of endogenous HIF-1alpha proteins in nuclei of normoxic cells. The induced HIF-1alpha 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 The effect of the SD was dependent on Pro564 since a mutated SD, in which Pro564 had been replaced by a glycine residue, failed to bind the von Hippel-Lindau protein (pVHL) and to stabilise HIF-1alpha. 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-1alpha degradation, either by saturation, or inhibition of prolyl hydroxylases or proteosomal degradation, leads to nuclear localisation of active HIF-1alpha proteins.
Place, publisher, year, edition, pages
2005. Vol. 306, no 1, 180-191 p.
Hypoxia, Hypoixa-Inducible Factor-1, Vascular Endothelial Growth Factor, von Hippel-Lindau
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-73220DOI: 10.1016/j.yexcr.2005.01.017PubMedID: 15878343OAI: oai:DiVA.org:uu-73220DiVA: diva2:101131