title: Mediator complex recruits epigenetic regulators via its two cyclin-dependent kinase subunits to repress transcription of immune response genes.
abstract: The Mediator complex (Mediator) plays pivotal roles in activating transcription by RNA polymerase II, but relatively little is known about its roles in repression. Here, we identified the histone arginine methyltransferase PRMT5 and WD repeat protein 77/methylosome protein 50 (WDR77/MEP50) as Mediator cyclin-dependent kinase (CDK)-interacting proteins and studied the roles of PRMT5 in the transcriptional regulation of CCAAT enhancer-binding protein (C/EBP) β target genes. First, we purified CDK8- and CDK19-containing complexes from HeLa nuclear extracts and subjected these purified complexes to mass spectrometric analyses. These experiments revealed that two Mediator CDKs, CDK8 and CDK19, individually interact with PRMT5 and WDR77, and their interactions with PRMT5 cause transcriptional repression of C/EBPβ target genes by regulating symmetric dimethylation of histone H4 arginine 3 (H4R3me2s) in the promoter regions of those genes. Furthermore, the recruitment of the DNA methyltransferase DNMT3A correlated with H4R3 dimethylation potentially leading to DNA methylation at the promoter proximal region and tight inhibition of preinitiation complex formation. In vertebrates, C/EBPβ regulates many genes involved in immune responses and cell differentiation. These findings shed light on the molecular mechanisms of the repressive roles of Mediator CDKs in transcription of C/EBPβ target genes and might provide clues that enable future studies of the functional associations between Mediators and epigenetic regulation.
authors.affiliation: From the Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, and.
authors.forename: Taiki
authors.initials: T
authors.lastname: Tsutsui
authors.affiliation: From the Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, and.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Fukasawa
authors.affiliation: the Mass Spectrometry Analysis Unit, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Shinmyouzu
authors.affiliation: the Mass Spectrometry Analysis Unit, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Nakagawa
authors.affiliation: the First Department of Internal Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan and.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Tobe
authors.affiliation: From the Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, and.
authors.forename: Aki
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: From the Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, and. Electronic address: ohkumay@pha.u-toyama.ac.jp.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ohkuma
mesh_terms: D001120:Arginine / Q000378:metabolism; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D002457:Cell Extracts; D056850:Cyclin-Dependent Kinase 8 / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D000090205:DNA Methyltransferase 3A; D044127:Epigenesis, Genetic; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007109:Immunity / Q000235:genetics*; D056892:Mediator Complex / Q000378:metabolism*; D008745:Methylation; D008954:Models, Biological; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D021122:Protein Subunits / Q000378:metabolism; D011484:Protein-Arginine N-Methyltransferases / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; C545012:CEBPB protein, human; D002457:Cell Extracts; C000717967:DNMT3A protein, human; D006657:Histones; D056892:Mediator Complex; D021122:Protein Subunits; D012097:Repressor Proteins; D014157:Transcription Factors; C478359:WDR77 protein, human; D001120:Arginine; C400529:PRMT5 protein, human; D011484:Protein-Arginine N-Methyltransferases; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; C584437:CDK19 protein, human; C095686:CDK8 protein, human; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases
keywords: CDK (Cyclin-dependent Kinase); DNA Methyltransferase; Phorbol Esters; RNA Polymerase II; Transcription Regulation; siRNA