Viral RNA silencing suppressors inhibit the microRNA pathway at an intermediate step

RNA silencing suppressors from different plant viruses are structurally diverse. In addition to inhibiting the antiviral silencing response to condition susceptibility, many suppressors are pathogenicity factors that cause disease or developmental abnormalities. Here, unrelated suppressors from mult...

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Bibliographic Details
Published in:Genes & development 2004-05, Vol.18 (10), p.1179-1186
Main Authors: Chapman, Elisabeth J, Prokhnevsky, Alexey I, Gopinath, Kodetham, Dolja, Valerian V, Carrington, James C
Format: Article
Language:English
Subjects:
Arabidopsis - genetics
Arabidopsis - growth & development
Arabidopsis - virology
Arabidopsis thaliana
Base Sequence
Genes, Viral
MicroRNAs - genetics
Models, Genetic
Plant Diseases - genetics
Plant Diseases - virology
Plant Viruses - genetics
Plant Viruses - pathogenicity
Plants, Genetically Modified
Research Papers
RNA Interference
RNA, Viral - genetics
Suppression, Genetic
Tombusvirus - genetics
Tombusvirus - pathogenicity
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Summary:RNA silencing suppressors from different plant viruses are structurally diverse. In addition to inhibiting the antiviral silencing response to condition susceptibility, many suppressors are pathogenicity factors that cause disease or developmental abnormalities. Here, unrelated suppressors from multiple viruses were shown to inhibit microRNA (miRNA) activities and trigger an overlapping series of severe developmental defects in transgenic Arabidopsis thaliana. This suggests that interference with miRNA-directed processes may be a general feature contributing to pathogenicity of many viruses. A normally labile intermediate in the miRNA biogenesis/RNA-induced silencing complex (RISC) assembly pathway, miRNA*, accumulated specifically in the presence of suppressors (P1/HC-Pro, p21, or p19) that inhibited miRNA-guided cleavage of target mRNAs. Both p21 and p19, but not P1/HC-Pro, interacted with miRNA/miRNA* complexes and hairpin RNA-derived short interfering RNAs (siRNAs) in vivo. In addition, p21 bound to synthetic miRNA/miRNA* and siRNA duplexes in vitro. We propose that several different suppressors act by distinct mechanisms to inhibit the incorporation of small RNAs into active RISCs.
ISSN:0890-9369
1549-5477
DOI:10.1101/gad.1201204