TY - JOUR T1 - The Methyl Transferase PRMT1 Functions as Co-Activator of Farnesoid X Receptor (FXR)/9-<em>cis</em> Retinoid X Receptor and Regulates Transcription of FXR Responsive Genes JF - Molecular Pharmacology JO - Mol Pharmacol SP - 551 LP - 558 DO - 10.1124/mol.105.012104 VL - 68 IS - 2 AU - Giovanni Rizzo AU - Barbara Renga AU - Elisabetta Antonelli AU - Daniela Passeri AU - Roberto Pellicciari AU - Stefano Fiorucci Y1 - 2005/08/01 UR - http://molpharm.aspetjournals.org/content/68/2/551.abstract N2 - The farnesoid X receptor (FXR) is a nuclear receptor that functions as an endogenous sensor for bile acids (BAs). FXR is bound to and activated by bile acid, and chenodeoxycholic acid (CDCA) is the natural most active ligand. Upon activation, FXR heterodimerizes with the 9-cis retinoic X receptor (RXR) and regulates genes involved in cholesterol and BA homeostasis. 6-Ethyl CDCA (6-ECDCA) is a synthetic BA that binds FXR and induces gene transcription by recruiting coactivators, such as steroid receptor coactivator-1, with histone acetyltransferase activity. In addition to acetylation, histone methylation is critically involved in regulating eukaryotic gene expression. In the present study, we demonstrated that 6-ECDCA activates FXR to interacts with Protein Arginine Methyl-Transferase type I (PRMT1), which induces up-regulation of bile salt export pump (BSEP) and the small heterodimer partner (SHP) mRNA expression and causes a down-regulation of P450 cholesterol 7α-hydroxylase and Na+ taurocholate cotransport peptide genes. Chromatin immunoprecipitation assay suggests that 6-ECDCA induces both the recruitment of PRMT1 and the H4 methylation to the promoter of BSEP and SHP genes. We also provide evidence that a methyltransferase inhibitor blocks the activation of FXR-responsive genes. Our results indicate that histone methylation, similar to acetylation, regulates transcriptional activation of genes involved in cholesterol and BAs homeostasis. ER -