Abstract |
We studied the expression of glutamine: fructose-6-phosphate amidotransferase (GFAT), the rate limiting enzyme in the hexosamine biosynthetic pathway controlling protein glycosylation. We obtained the first evidence that the GFAT mRNA and protein are constitutively expressed in murine mononuclear phagocytes (Mf) and inducible by picolinic acid (PA), a catabolite of tryptophan, hypoxia and desferrioxamine (DFX). These stimuli share the property to transactivate gene expression through the Hypoxia Responsive Element (HRE). The promoter of GFAT contains the consensus sequence of HRE in position 74/-65 (GFAT-HRE), and we studied the role of HRE on the activation of the promoter utilizing appropriate expression vectors. We found that GFAT-HRE is essential for the response to hypoxia, PA or DFX and that Hypoxia Inducible Factor-1alpha (HIF-1alpha) can augment this response. Finally, we demonstrate that iron chelation is part of the mechanism by which PA and DFX activate GFAT expression. Our results provide the first indication that hypoxia, PA or DFX induce the transcription of GFAT gene in murine Mf cell lines and that the HRE of the promoter is essential for this response.
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Authors | B Manzari, J E Kudlow, P Fardin, E Merello, C Ottaviano, M Puppo, A Eva, L Varesio |
Journal | International journal of immunopathology and pharmacology
(Int J Immunopathol Pharmacol)
2007 Jan-Mar
Vol. 20
Issue 1
Pg. 47-58
ISSN: 0394-6320 [Print] England |
PMID | 17346427
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Hypoxia-Inducible Factor 1, alpha Subunit
- Iron Chelating Agents
- Picolinic Acids
- RNA, Messenger
- Tryptophan
- Luciferases
- Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)
- Deferoxamine
- picolinic acid
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Topics |
- Animals
- Blotting, Northern
- Breast Neoplasms
(enzymology)
- Cell Hypoxia
(physiology)
- Cell Line
- Cell Line, Tumor
- Deferoxamine
(pharmacology)
- Female
- Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)
(biosynthesis)
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit
(physiology)
- Iron Chelating Agents
(pharmacology)
- Luciferases
(genetics)
- Macrophages
(drug effects, enzymology, physiology)
- Mice
- Oligonucleotide Array Sequence Analysis
- Picolinic Acids
(pharmacology)
- Plasmids
(genetics)
- RNA, Messenger
(biosynthesis, genetics)
- Transfection
- Tryptophan
(physiology)
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