Recruitment of CREB1 and histone deacetylase 2 (HDAC2) to the mouse Ltbp-1 promoter regulates its constitutive expression in a dioxin receptor-dependent manner

被引：33

作者：

Gomez-Duran, Aurea ^{[1
]}

Ballestar, Esteban ^{[2
]}

Carvajal-Gonzalez, Jose M. ^{[1
]}

Marlowe, Jennifer L. ^{[3
]}

Puga, Alvaro ^{[3
]}

Esteller, Manel ^{[2
]}

Fernandez-Salguero, Pedro M. ^{[1
]}

机构：

[1] Univ Extremadura, Dept Bioquim & Biol Mol, Fac Ciencias, E-06071 Badajoz, Spain

[2] CNIO, Lab Epigenet Canc, Programa Patol Mol, Madrid 28029, Spain

[3] Univ Cincinnati, Med Ctr, Dept Environm Hlth, Cincinnati, OH 45267 USA

来源：

JOURNAL OF MOLECULAR BIOLOGY | 2008年 / 380卷 / 01期

关键词：

LTBP-1; dioxin receptor; CREB1; HDAC2; transcriptional regulation;

D O I：

10.1016/j.jmb.2008.04.056

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Latent TGF beta-binding protein 1 (LTBP-1) is a key regulator of TGF beta targeting and activation in the extracellular matrix. LTBP-1 is recognized as a major docking molecule to localize, and possibly to activate, TGF beta in the extracellular matrix. Despite this relevant function, the molecular mechanisms regulating Ltbp-1 transcription remain largely unknown. Previous results from our laboratory revealed that mouse embryonic fibroblasts (MEF) lacking dioxin receptor (AhR) had increased Ltbp(-1) mRNA expression and elevated TGF beta activity, suggesting that AhR repressed Ltbp(-1) transcription. Here, we have cloned the mouse Ltbp(-1) gene promoter and analysed its mechanism of transcriptional repression by AhR. Reporter gene assays, AhR over-expression and site-directed mutagenesis showed that basal Ltbp-1 transcription is AhR-dependent. Chromatin immunoprecipitation (ChIP) and RNA interference (RNAi) revealed that AhR regulates Ltbp-1 transcription by a mechanism involving recruitment of co-activators such as CREB1 and co-repressors such as HDAC2 to the Ltbp-1 promoter. In AhR-expressing (AhR+/+) MEF cells, the recruitment of HDAC1, 2 and 4 correlated with decreased K8H4 acetylation and impaired binding of pCREB(Ser133) to the Ltbp-1 promoter, likely maintaining a constitutive repressed state. AhR-/- MEF cells had the opposite pattern of HDACs and pCREB1(Ser133) binding to Ltbp-1 promoter, and therefore, over-expressed Ltbp-1 mRNA. In agreement, siRNA for HDAC2 increased Ltbp-1 expression and K8H4 acetylation in AhR+/+ but not in AhR-/- MEF cells. We suggest that HDAC2 binding keeps Ltbp-1 promoter repressed in AhR+/+ MEF cells, whereas in AhR-null MEF cells the absence of HDAC2 and the binding of pCREB(Ser133) allow Ltbp-1 transcription. Thus, epigenetics can contribute to constitutive Ltbp-1 repression by a mechanism requiring AhR activity. (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：1 / 16

页数：16