Sp family of transcription factors is involved in iron-induced collagen alpha 1(I) gene expression

Citation
Ig. Ruiz et al., Sp family of transcription factors is involved in iron-induced collagen alpha 1(I) gene expression, DNA CELL B, 19(3), 2000, pp. 167-178
Citations number
67
Categorie Soggetti
Molecular Biology & Genetics
Journal title
DNA AND CELL BIOLOGY
ISSN journal
10445498 → ACNP
Volume
19
Issue
3
Year of publication
2000
Pages
167 - 178
Database
ISI
SICI code
1044-5498(200003)19:3<167:SFOTFI>2.0.ZU;2-M
Abstract
The purpose of this study was to identify the cis-acting elements and the t rans-acting factors involved in the iron-induced expression of the collagen alpha 1(I) (COL1 alpha I) gene. Rat hepatic stellate cells were cultured i n the presence of 50 mu M ferric chloride, 50 mu M ascorbic acid, and 250 m u M citric acid (Fe/AA/CA), and the effects on collagen gene expression and the binding of nuclear proteins to the COL1aI promoter were measured, The Fe/AA/CA treatment induced a time- and dose-dependent increase in the cellu lar levels of COL1aI mRNA that was abrogate by pretreating cells with cyclo heximide, antioxidants, and inhibitors of aldehyde-protein adduct formation . Transient transfection experiments showed that Fe/AA/CA exerted its effec t through regulatory elements located between -220 and -110 bp of the COL1a I promoter. Gel retardation assays showed that Fe/AA/CA increased the bindi ng of nuclear proteins to two elements located between -161 and -110 bp of the COL1aI promoter. These bindings were blocked by unlabeled consensus Spl oligonucleotide and supershifted with Sp1 and Sp3 antibodies. Finally, Fe/ AA/CA increased cellular levels of the Spl and Sp3 proteins and Spl mRNA, T reatment with Fe/AA/CA stimulates COL1aI gene expression by inducing the sy nthesis of Spl and Sp3 and their binding to two regulatory elements located between -161 and -110 bp of the COL1aI promoter.