Project name: Arabidopsis thaliana

Description: MicroRNAs (miRNAs) and small-interfering RNAs (siRNAs) negatively regulate their targets by 1) repressing translation, 2) endonucleolytic RNA cleavage, or 3) DNA methylation resulting in transcriptional silencing. P-body/decapping components are likely required for translational repression, but are not known to function in other posttranscriptional regulatory pathways or to affect smRNA levels. Here, we show that the P-body/decapping protein DCP5 is required for miRNA-mediated translational repression but not cleavage, and to regulate the transcription of specific miRNAs. We find that this protein also affects the abundance of tRNA-derived smRNAs. Significantly, DCP5 is required for the transcriptional silencing and DNA methylation of numerous transposable/repetitive elements and imprinted genes, indicating that it is a novel component of the RNA-directed DNA methylation pathway. Our results demonstrate that DCP5 and likely the P-body itself are required for multiple smRNA-mediated silencing pathways and provide the first evidence for the spatial separation of translational inhibition and cleavage by miRNAs.Overall design: total RNA expression comparison with between wildtype (Col-0) and dcp5 mutant plants in Arabidopsis

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: ModelOrganism

Last updated: 2011-04-11