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SDE5, the putative homologue of a human mRNA export factor, is required for transgene silencing and accumulation of trans ‐acting endogenous siRNA
Author(s) -
HernandezPinzon Inmaculada,
Yelitaliya E.,
Schwach Frank,
Studholme David J.,
Baulcombe David,
Dalmay Tamas
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2007.03043.x
Subject(s) - rna silencing , biology , trans acting sirna , rna induced silencing complex , rna induced transcriptional silencing , rna , argonaute , small interfering rna , gene silencing , genetics , transgene , small rna , rna interference , dicer , microbiology and biotechnology , gene
Summary Post‐transcriptional gene silencing (PTGS) is a sequence‐specific RNA degradation process conserved in fungi, plants and animals. The trigger of the mechanism is double‐stranded RNA derived from transgenic or endogenous loci and formed by intra‐ or inter‐molecular interactions of single‐stranded RNAs or the action of RNA‐dependent RNA polymerases (RDRs). Double‐stranded RNA from various sources is processed by one of the four Dicer‐like (DCL) proteins in Arabidopsis, and the resulting short RNAs enter into at least four different pathways, one of which involves the production of trans ‐acting short interfering RNAs (tasiRNAs). We report here a novel gene ( SDE5 ) that is required for transgene silencing and the production of tasiRNAs. Mutation in SDE5 also results in hyper‐susceptibility to cucumber mosaic virus but not turnip mosaic virus. However, like RDR6, SDE5 is not involved in inverted repeat‐induced transgene silencing or the biogenesis of microRNAs and 24 nt siRNAs produced by DCL3. Based on these results, we propose that SDE5 acts together with RDR6 in generating double‐stranded RNA from specific single‐stranded RNAs. As the sequence of SDE5 has sequence features shared by TAP, a human mRNA export factor, we propose that its role could be in the transport of RNA molecules that are converted into a double‐stranded form by RDR6.