NRF-1 and HIF-1α contribute to modulation of human VDAC1 gene promoter during starvation and hypoxia in HeLa cells
Biochimica et Biophysica Acta (BBA) - Bioenergetics. 2020-12-01; 1861(12): 148289
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Guarino F(1), Zinghirino F(2), Mela L(2), Pappalardo XG(2), Ichas F(3), De Pinto V(4), Messina A(5).
(1)Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95123 Catania, Italy. Electronic address: .
(2)Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95123 Catania, Italy.
(3)CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Université de Bordeaux, Bordeaux, France; INSERM, Laboratoire de Neurosciences Expérimentales et Cliniques, U-1084, Université de Poitiers, Poitiers, France.
(4)Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia 64, 95123 Catania, Italy; National Institute for Biostructures and Biosystems, Section of Catania, Rome, Italy. Electronic address: .
(5)Department of Biological, Geological and Environmental Sciences, Section of Molecular Biology, University of Catania, Viale A. Doria 6, 95125 Catania, Italy; National Institute for Biostructures and Biosystems, Section of Catania, Rome, Italy.
VDAC (Voltage Dependent Anion Channel) is a family of pore forming protein
located in the outer mitochondrial membrane. Its channel property ensures
metabolites exchange between mitochondria and the rest of the cell resulting in
metabolism and bioenergetics regulation, and in cell death and life switch. VDAC1
is the best characterized and most abundant isoform, and is involved in many
pathologies, as cancer or neurodegenerative diseases. However, little information
is available about its gene expression regulation in normal and/or pathological
conditions. In this work, we explored VDAC1 gene expression regulation in normal
conditions and in the contest of some metabolic and energetic mitochondrial
dysfunction and cell stress as example. The core of the putative promoter region
was characterized in terms of transcription factors responsive elements both by
bioinformatic studies and promoter activity experiments. In particular, we found
an abundant presence of NRF-1 sites, together with other transcription factors
binding sites involved in cell growth, proliferation, development, and we studied
their prevalence in gene activity. Furthermore, upon depletion of nutrients or
controlled hypoxia, as detected in various pathologies, we found that VDAC1
transcripts levels were significantly increased in a time related manner. VDAC1
promoter activity was also validated by gene reporter assays. According to PCR
real-time experiments, it was confirmed that VDAC1 promoter activity is further
stimulated when cells are exposed to stress. A bioinformatic survey suggested
HIF-1α, besides NRF-1, as a most active TFBS. Their validation was obtained by
TFBS mutagenesis and TF overexpression experiments. In conclusion, we
experimentally demonstrated the involvement of both NRF-1 and HIF-1α in the
regulation of VDAC1 promoter activation at basal level and in some peculiar cell
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