title: Spreading of RNA targeting and DNA methylation in RNA silencing requires transcription of the target gene and a putative RNA-dependent RNA polymerase.
abstract: RNA silencing is a sequence-specific RNA degradation process that follows the recognition of double-stranded RNA. Here, we show that virus vectors carrying parts of a green fluorescent protein (GFP) transgene targeted RNA silencing in Nicotiana benthamiana and Arabidopsis against the entire GFP RNA. These results indicate that there was spreading of RNA targeting from the initiator region into the adjacent 5' and 3' regions of the target gene. Spreading was accompanied by methylation of the corresponding GFP DNA. It also was dependent on transcription of the transgene and on the putative RNA-dependent RNA polymerase, SDE1/SGS2. These findings indicate that SDE1/SGS2 produces double-stranded RNA using the target RNA as a template. RNA silencing of ribulose-1,5-bisphosphate carboxylase/oxygenase and phytoene desaturase was not associated with the spreading of RNA targeting or DNA methylation, indicating that these endogenous RNAs are not templates for SDE1/SGS2.
authors.affiliation: Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom.
authors.forename: Fabián E
authors.initials: FE
authors.lastname: Vaistij
authors.forename: Louise
authors.initials: L
authors.lastname: Jones
authors.forename: David C
authors.initials: DC
authors.lastname: Baulcombe
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins; D019175:DNA Methylation; D020868:Gene Silencing; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D034743:RNA-Induced Silencing Complex; D012261:Ribonucleoproteins; C410506:SGS2 protein, Arabidopsis; D049452:Green Fluorescent Proteins; D010088:Oxidoreductases; C022398:phytoene dehydrogenase; D012324:RNA-Dependent RNA Polymerase; D012273:Ribulose-Bisphosphate Carboxylase