title: Small RNA binding is a common strategy to suppress RNA silencing by several viral suppressors.
abstract: RNA silencing is an evolutionarily conserved system that functions as an antiviral mechanism in higher plants and insects. To counteract RNA silencing, viruses express silencing suppressors that interfere with both siRNA- and microRNA-guided silencing pathways. We used comparative in vitro and in vivo approaches to analyse the molecular mechanism of suppression by three well-studied silencing suppressors. We found that silencing suppressors p19, p21 and HC-Pro each inhibit the intermediate step of RNA silencing via binding to siRNAs, although the molecular features required for duplex siRNA binding differ among the three proteins. None of the suppressors affected the activity of preassembled RISC complexes. In contrast, each suppressor uniformly inhibited the siRNA-initiated RISC assembly pathway by preventing RNA silencing initiator complex formation.
authors.affiliation: Agricultural Biotechnology Center, Plant Biology Institute, Gödöllõ, Hungary.
authors.forename: Lóránt
authors.initials: L
authors.lastname: Lakatos
authors.forename: Tibor
authors.initials: T
authors.lastname: Csorba
authors.forename: Vitantonio
authors.initials: V
authors.lastname: Pantaleo
authors.forename: Elisabeth J
authors.initials: EJ
authors.lastname: Chapman
authors.forename: James C
authors.initials: JC
authors.lastname: Carrington
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Liu
authors.forename: Valerian V
authors.initials: VV
authors.lastname: Dolja
authors.forename: Lourdes Fernández
authors.initials: LF
authors.lastname: Calvino
authors.forename: Juan José
authors.initials: JJ
authors.lastname: López-Moya
authors.forename: József
authors.initials: J
authors.lastname: Burgyán
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000821:virology; D020029:Base Pairing; D004330:Drosophila / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism*; D018515:Plant Leaves / Q000821:virology; D010942:Plant Viruses / Q000502:physiology*; D034622:RNA Interference; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000378:metabolism; D014026:Nicotiana / Q000821:virology; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D034741:RNA, Small Interfering; D034743:RNA-Induced Silencing Complex; D014764:Viral Proteins