Smads orchestrate specific histone modifications and chromatin remodeling to activate transcription

Smads are intracellular transducers for TGF‐β superfamily ligands, but little is known about the mechanism by which complexes of receptor‐phosphorylated Smad2 and Smad4 regulate transcription. Using an in vitro transcription system, we have discovered that, unlike most transcription factors that are...

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Bibliographic Details
Published inThe EMBO journal Vol. 25; no. 19; pp. 4490 - 4502
Main Authors Ross, Sarah, Cheung, Edwin, Petrakis, Thodoris G, Howell, Michael, Kraus, W Lee, Hill, Caroline S
Format Journal Article
LanguageEnglish
Published Chichester, UK John Wiley & Sons, Ltd 04.10.2006
Blackwell Publishing Ltd
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Summary:Smads are intracellular transducers for TGF‐β superfamily ligands, but little is known about the mechanism by which complexes of receptor‐phosphorylated Smad2 and Smad4 regulate transcription. Using an in vitro transcription system, we have discovered that, unlike most transcription factors that are sufficient to recruit the basal transcription machinery and therefore activate transcription on both naked DNA and chromatin templates, the Smads only activate transcription from chromatin templates. We demonstrate that Smad2‐mediated transcription requires the histone acetyltransferase, p300. Smad2‐recruited p300 exhibits an altered substrate specificity, specifically acetylating nucleosomal histone H3 at lysines 9 and 18, and these modifications are also detected on an endogenous Smad2‐dependent promoter in a ligand‐induced manner. Furthermore, we show that endogenous Smad2 interacts with the SWI/SNF ATPase, Brg1, in a TGF‐β‐dependent manner, and demonstrate that Brg1 is recruited to Smad2‐dependent promoters and is specifically required for TGF‐β‐induced expression of endogenous Smad2 target genes. Our data indicate that the Smads define a new class of transcription factors that absolutely require chromatin to assemble the basal transcription machinery and activate transcription.
Bibliography:ark:/67375/WNG-7Q022JDR-C
Supplementary dataSupplementary FiguresSupplementary Figures
istex:2CFA4D9D011751E85B8EA379C5EA536DB1C72B2C
ArticleID:EMBJ7601332
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
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These authors contributed equally to this work
ISSN:0261-4189
1460-2075
DOI:10.1038/sj.emboj.7601332