title: Molecular architecture of human polycomb repressive complex 2.
abstract: Polycomb Repressive Complex 2 (PRC2) is essential for gene silencing, establishing transcriptional repression of specific genes by tri-methylating Lysine 27 of histone H3, a process mediated by cofactors such as AEBP2. In spite of its biological importance, little is known about PRC2 architecture and subunit organization. Here, we present the first three-dimensional electron microscopy structure of the human PRC2 complex bound to its cofactor AEBP2. Using a novel internal protein tagging-method, in combination with isotopic chemical cross-linking and mass spectrometry, we have localized all the PRC2 subunits and their functional domains and generated a detailed map of interactions. The position and stabilization effect of AEBP2 suggests an allosteric role of this cofactor in regulating gene silencing. Regions in PRC2 that interact with modified histone tails are localized near the methyltransferase site, suggesting a molecular mechanism for the chromatin-based regulation of PRC2 activity.DOI:http://dx.doi.org/10.7554/eLife.00005.001.
authors.affiliation: Department of Molecular and Cell Biology ,  University of California ,  Berkeley ,  United States.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ciferri
authors.forename: Gabriel C
authors.initials: GC
authors.lastname: Lander
authors.forename: Alessio
authors.initials: A
authors.lastname: Maiolica
authors.forename: Franz
authors.initials: F
authors.lastname: Herzog
authors.forename: Ruedi
authors.initials: R
authors.lastname: Aebersold
authors.forename: Eva
authors.initials: E
authors.lastname: Nogales
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D016367:Baculoviridae; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure*; D020868:Gene Silencing; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008745:Methylation; D008854:Microscopy, Electron; D008958:Models, Molecular; D008968:Molecular Conformation; D063151:Polycomb Repressive Complex 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D061987:Sf9 Cells; D018411:Spodoptera
chemical_list: C119809:AEBP2 protein, human; D002843:Chromatin; D006657:Histones; D021122:Protein Subunits; D011994:Recombinant Proteins; D012097:Repressor Proteins; D063151:Polycomb Repressive Complex 2
keywords: Gene silencing; Human; chemical cross-linking; chromatin; cryo-EM; labeling