A Pol V-mediated silencing, independent of RNA-directed DNA methylation, applies to 5S rDNA.
The plant-specific RNA polymerases Pol IV and Pol V are essential to RNA-directed DNA methylation (RdDM), which also requires activities from RDR2 (RNA-Dependent RNA Polymerase 2), DCL3 (Dicer-Like 3), AGO4 (Argonaute), and DRM2 (Domains Rearranged Methyltransferase 2). RdDM is dedicated to the meth...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2009-10-01
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| Series: | PLoS Genetics |
| Online Access: | http://europepmc.org/articles/PMC2754527?pdf=render |
| Summary: | The plant-specific RNA polymerases Pol IV and Pol V are essential to RNA-directed DNA methylation (RdDM), which also requires activities from RDR2 (RNA-Dependent RNA Polymerase 2), DCL3 (Dicer-Like 3), AGO4 (Argonaute), and DRM2 (Domains Rearranged Methyltransferase 2). RdDM is dedicated to the methylation of target sequences which include transposable elements, regulatory regions of several protein-coding genes, and 5S rRNA-encoding DNA (rDNA) arrays. In this paper, we have studied the expression of the 5S-210 transcript, a marker of silencing release at 5S RNA genes, to show a differential impact of RNA polymerases IV and V on 5S rDNA arrays during early development of the plant. Using a combination of molecular and cytological assays, we show that Pol IV, RDR2, DRM2, and Pol V, actors of the RdDM, are required to maintain a transcriptional silencing of 5S RNA genes at chromosomes 4 and 5. Moreover, we have shown a derepression associated to chromatin decondensation specific to the 5S array from chromosome 4 and restricted to the Pol V-loss of function. In conclusion, our results highlight a new role for Pol V on 5S rDNA, which is RdDM-independent and comes specifically at chromosome 4, in addition to the RdDM pathway. |
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| ISSN: | 1553-7390 1553-7404 |