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A plant RNA virus suppresses RNA silencing through viral RNA replication
Author(s) -
Takeda Atsushi,
Tsukuda Misato,
Mizumoto Hiroyuki,
Okamoto Kimiyuki,
Kaido Masanori,
Mise Kazuyuki,
Okuno Tetsuro
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600776
Subject(s) - biology , rna silencing , rna , rna induced silencing complex , rna dependent rna polymerase , trans acting sirna , virology , rna induced transcriptional silencing , viral replication , plant virus , rna editing , rna interference , genetics , virus , gene
RNA interference (RNAi) is a post‐transcriptional gene‐regulatory mechanism that operates in many eukaryotes. RNAi is induced by double‐stranded RNA (dsRNA) and is mainly involved in defence against transposons and viruses. To counteract RNAi, viruses have RNAi suppressors. Here we show a novel mechanism of RNAi suppression by a plant virus Red clover necrotic mosaic virus (RCNMV). To suppress RNAi, RCNMV needs multiple viral components, which include viral RNAs and putative RNA replicase proteins. A close relationship between the RNA elements required for negative‐strand RNA synthesis and RNAi suppression suggests a strong link between the viral RNA replication machinery and the RNAi machinery. In a transient assay, RCNMV interferes with the accumulation of small‐interfering RNA (siRNAs) in RNAi induced by a hairpin dsRNA and it also interferes with microRNA (miRNA) biogenesis. An Arabidopsis dcl1 mutant showed reduced susceptibility to RCNMV infection. Based on these results, we propose a model in which, to replicate, RCNMV deprives the RNAi machinery of Dicer‐like enzymes that are involved in both siRNA and miRNA biogenesis.