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Regulation of ferrochelatase gene expression by hypoxia
Yunying L Liu1, Sonny O Ang, Douglas A Weigent
1Department of Medicine, Liver Center, University of Alabama at Birmingham, 35294-0005, USA.
Life Sciences
|August 18, 2004
Summary
Hypoxia upregulates ferrochelatase (FECH) gene expression via hypoxia-inducible factor 1 (HIF-1). This study reveals FECH as a direct target of HIF-1, impacting heme biosynthesis under low-oxygen conditions.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- The heme biosynthetic pathway is crucial for producing heme, essential for hemoglobin and hemoproteins.
- The regulatory role of oxygen in this pathway, particularly concerning ferrochelatase (FECH), remains unclear.
Purpose of the Study:
- To investigate if hypoxia-inducible factor 1 (HIF-1) upregulates ferrochelatase (FECH) gene expression during hypoxia.
- To determine if FECH is a direct transcriptional target of HIF-1.
Main Methods:
- Bioinformatic analysis identified HIF-1 binding motifs in the FECH promoter.
- Cellular experiments exposed HEL, K562, and Hep-G2 cells to hypoxia.
- Luciferase reporter assays assessed FECH promoter activity with varying HIF-1alpha and von Hippel-Lindau (VHL) expression.
Main Results:
- Hypoxia significantly increased FECH mRNA expression in multiple cell lines (p < 0.05).
- Hypoxia transactivated the minimal FECH promoter.
- HIF-1alpha expression stimulated FECH promoter activity, while dominant-negative HIF-1alpha or VHL expression blocked it.
Conclusions:
- The ferrochelatase (FECH) gene is a direct transcriptional target of hypoxia-inducible factor 1 (HIF-1).
- FECH gene expression is upregulated by HIF-1 during hypoxic conditions, suggesting a role in cellular adaptation to low oxygen.