Transforming growth factor β-inducible independent binding of SMAD to the Smad7 promoter Journal Article


Authors: Denissova, N. G.; Pouponnot, C.; Long, J.; He, D.; Liu, F.
Article Title: Transforming growth factor β-inducible independent binding of SMAD to the Smad7 promoter
Abstract: SMAD proteins can mediate transforming growth factor β (TGF-β)- inducible transcriptional responses. Whereas SMAD can recognize specific DNA sequences, it is usually recruited to a promoter through interaction with a DNA-binding partner. In an effort to search for TGF-β-inducible genes, we used a subtractive screening method and identified human Smad7, which can antagonize TGF-β signaling and is rapidly up-regulated by TGF-β. In this report, we show that TGF-β can stabilize Smad7 mRNA and activate Smad7 transcription. The Smad7 promoter is the first TGF-β responsive promoter identified in vertebrates that contains the 8-bp palindromic SMAD-binding element (SBE), an optimal binding site previously identified by a PCR-based selection from random oligonucleotides by using recombinant Smad3 and Smad4. We demonstrate that on TGF-β treatment, endogenous SMAD complex can bind to a Smad7 promoter DNA as short as 14 or 16 bp that contains the 8-bp SBE in gel mobility shift and supershift assays. Our studies provide strong evidence that SMAD proteins can bind to a natural TGF-β responsive promoter independent of other sequence-specific transcription factors. We further show that, whereas recombinant Smad3 binds to the SBE, endogenous or even transfected Smad3 cannot bind to the SBE in the absence of Smad4. These findings have important implications in the identification of target genes of the TGF-β/SMAD signaling pathways.
Keywords: human cell; dna-binding proteins; polymerase chain reaction; gene targeting; smad3 protein; smad7 protein; transforming growth factor beta; protein binding; molecular sequence data; rna, messenger; base sequence; binding site; gene control; dna sequence; trans-activators; gene induction; protein dna interaction; smad4 protein; promoter regions (genetics); humans; human; priority journal; article
Journal Title: Proceedings of the National Academy of Sciences of the United States of America
Volume: 97
Issue: 12
ISSN: 0027-8424
Publisher: National Academy of Sciences  
Date Published: 2000-06-06
Start Page: 6397
End Page: 6402
Language: English
DOI: 10.1073/pnas.090099297
PUBMED: 10823886
PROVIDER: scopus
PMCID: PMC18614
DOI/URL:
Notes: Export Date: 18 November 2015 -- Source: Scopus
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