RT Journal Article
SR Electronic
T1 In plants, decapping prevents RDR6-dependent production of small interfering RNAs from endogenous mRNAs
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 013912
DO 10.1101/013912
A1 Angel Emilio Martínez de Alba
A1 Ana Beatriz Moreno
A1 Marc Gabriel
A1 Allison C. Mallory
A1 Aurélie Christ
A1 Rémi Bounon
A1 Sandrine Balzergue
A1 Sebastien Aubourg
A1 Daniel Gautheret
A1 Martin D. Crespi
A1 Hervé Vaucheret
A1 Alexis Maizel
YR 2015
UL http://biorxiv.org/content/early/2015/01/16/013912.abstract
AB Cytoplasmic degradation of endogenous RNAs is an integral part of RNA quality control (RQC) and often relies on the removal of the 5’ cap structure and their subsequent 5’ to 3’ degradation in cytoplasmic processing (P-)bodies. In parallel, many eukaryotes degrade exogenous and selected endogenous RNAs through post-transcriptional gene silencing (PTGS). In plants, PTGS depends on small interfering (si)RNAs produced after the conversion of single-stranded RNAs to doublestranded RNAs by the cellular RNA DEPENDENT RNA POLYMERASE 6 (RDR6) in cytoplasmic siRNA-bodies. PTGS and RQC compete for transgene-derived RNAs, but it is unknown whether this competition also occurs for endogenous transcripts. Here, we show that the lethality of decapping mutants is suppressed by impairing RDR6 activity. We also show that upon decapping impairment hundreds of endogenous mRNAs give rise to a new class of siRNAs, a subset of which depends on RDR6 for their production. We observe that, in vivo, P- and siRNA-bodies often are juxtaposed and remain associated while moving in an actin-dependent manner, potentially allowing for cross-talk of the two machineries. Our results suggest that the decapping of aberrant endogenous RNA in P-bodies limits their entry into the PTGS pathway and prevents the subsequent deleterious consequences arising from this entry. We anticipate that the siRNAs identified in decapping mutants represent a subset of a larger ensemble of endogenous siRNAs. We call them rqc-siRNAs due to their over-accumulation when RQC processes are impaired.