3-Methylcholanthrene elicits DNA adduct formation in the CYP1A1 promoter region and attenuates reporter gene expression in rat H4IIE cells
Journal Article
·
· Biochemical and Biophysical Research Communications
- Department of Pediatrics, Baylor College of Medicine, 6621 Fannin, FC 530.01, Houston, TX 77030 (United States)
Cytochrome CYP1A (CYP1A) enzymes catalyze bioactivation of 3-methylcholanthrene (MC) to genotoxic metabolites. Here, we tested the hypothesis that CYP1A2 catalyzes formation of MC-DNA adducts that are preferentially formed in the promoter region of CYP1A1, resulting in modulation of CYP1A1 gene expression. MC bound covalently to plasmid DNA (50 {mu}g) containing human CYP1A1 promoter (pGL3-1A1), when incubated with wild-type (WT) liver microsomes (2 mg) and NAPPH 37 {sup o}C for 2 h, giving rise to 9 adducts, as determined by {sup 32}P-postlabeling. Eighty percent of adducts was located in the promoter region. Transient transfection of the adducted plasmids into rat hepatoma (H4IIE) cells for 16 h, followed by MC (1 {mu}M) treatment for 24 h inhibited reporter (luciferase) gene expression by 75%, compared to unadducted controls. Our results suggest that CYP1A2 plays a key role in sequence-specific MC-DNA adduct formation in the CYP1A1 promoter region, leading to attenuation of CYP1A1 gene expression.
- OSTI ID:
- 20979847
- Journal Information:
- Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 4 Vol. 354; ISSN 0006-291X; ISSN BBRCA9
- Country of Publication:
- United States
- Language:
- English
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Thu Mar 14 23:00:00 EST 1991
· FASEB Journal (Federation of American Societies for Experimental Biology); (United States)
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OSTI ID:5173553