title: Reiterated WG/GW motifs form functionally and evolutionarily conserved ARGONAUTE-binding platforms in RNAi-related components.
abstract: Two forms of RNA Polymerase IV (PolIVa/PolIVb) have been implicated in RNA-directed DNA methylation (RdDM) in Arabidopsis. Prevailing models imply a distinct function for PolIVb by association of Argonaute4 (AGO4) with the C-terminal domain (CTD) of its largest subunit NRPD1b. Here we show that the extended CTD of NRPD1b-type proteins exhibits conserved Argonaute-binding capacity through a WG/GW-rich region that functionally distinguishes Pol IVb from Pol IVa, and that is essential for RdDM. Site-specific mutagenesis and domain-swapping experiments between AtNRPD1b and the human protein GW182 demonstrated that reiterated WG/GW motifs form evolutionarily and functionally conserved Argonaute-binding platforms in RNA interference (RNAi)-related components.
authors.affiliation: Laboratoire Génome et Développement de Plantes, Centre National de la Recherche Scientifique/Institut de Recherche pour le Développement/Université de Perpignan 5096, 66860 Perpignan Cedex, France.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: El-Shami
authors.forename: Dominique
authors.initials: D
authors.lastname: Pontier
authors.forename: Sylvie
authors.initials: S
authors.lastname: Lahmy
authors.forename: Laurence
authors.initials: L
authors.lastname: Braun
authors.forename: Claire
authors.initials: C
authors.lastname: Picart
authors.forename: Danielle
authors.initials: D
authors.lastname: Vega
authors.forename: Mohamed-Ali
authors.initials: MA
authors.lastname: Hakimi
authors.forename: Steven E
authors.initials: SE
authors.lastname: Jacobsen
authors.forename: Richard
authors.initials: R
authors.lastname: Cooke
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 / Q000235:genetics / Q000378:metabolism*; D060565:Argonaute Proteins; D017124:Conserved Sequence; D019175:DNA Methylation; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D030821:Plants, Genetically Modified; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D034622:RNA Interference; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid
chemical_list: C471209:AGO4 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D021122:Protein Subunits; C499181:RNA polymerase IV, Arabidopsis; D012321:DNA-Directed RNA Polymerases