title: NERD, a plant-specific GW protein, defines an additional RNAi-dependent chromatin-based pathway in Arabidopsis.
abstract: In Arabidopsis, transcriptional gene silencing (TGS) can be triggered by 24 nt small-interfering RNAs (siRNAs) through the RNA-directed DNA methylation (RdDM) pathway. By functional analysis of NERD, a GW repeat- and PHD finger-containing protein, we demonstrate that Arabidopsis harbors a second siRNA-dependent DNA methylation pathway targeting a subset of nonconserved genomic loci. The activity of the NERD-dependent pathway differs from RdDM by the fact that it relies both on silencing-related factors previously implicated only in posttranscriptional gene silencing (PTGS), including RNA-DEPENDENT RNA POLYMERASE1/6 and ARGONAUTE2, and most likely on 21 nt siRNAs. A central role for NERD in integrating RNA silencing and chromatin signals in transcriptional silencing is supported by data showing that it binds both to histone H3 and AGO2 proteins and contributes to siRNA accumulation at a NERD-targeted locus. Our results unravel the existence of a conserved chromatin-based RNA silencing pathway encompassing both PTGS and TGS components in plants.
authors.affiliation: Laboratoire Génome et Développement des Plantes, Centre National de la Recherche Scientifique/Université de Perpignan via Domitia, UMR5096, Perpignan, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Pontier
authors.forename: Claire
authors.initials: C
authors.lastname: Picart
authors.forename: François
authors.initials: F
authors.lastname: Roudier
authors.forename: Damien
authors.initials: D
authors.lastname: Garcia
authors.forename: Sylvie
authors.initials: S
authors.lastname: Lahmy
authors.forename: Jacinthe
authors.initials: J
authors.lastname: Azevedo
authors.forename: Emilie
authors.initials: E
authors.lastname: Alart
authors.forename: Michèle
authors.initials: M
authors.lastname: Laudié
authors.forename: Wojciech M
authors.initials: WM
authors.lastname: Karlowski
authors.forename: Richard
authors.initials: R
authors.lastname: Cooke
authors.forename: Vincent
authors.initials: V
authors.lastname: Colot
authors.forename: Olivier
authors.initials: O
authors.lastname: Voinnet
authors.forename: Thierry
authors.initials: T
authors.lastname: Lagrange
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D060565:Argonaute Proteins; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019175:DNA Methylation; D006657:Histones / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; C577476:NERD protein, Arabidopsis; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C559855:argonaute 2 protein, Arabidopsis; C514575:RDR6 protein, Arabidopsis; D012324:RNA-Dependent RNA Polymerase