Double-stranded RNA binding proteins DRB2 and DRB4 have an antagonistic impact on polymerase IV-dependent siRNA levels in Arabidopsis - Archive ouverte HAL
Article Dans Une Revue RNA Année : 2011

Double-stranded RNA binding proteins DRB2 and DRB4 have an antagonistic impact on polymerase IV-dependent siRNA levels in Arabidopsis

Résumé

Biogenesis of the vast majority of plant siRNAs depends on the activity of the plant-specific RNA polymerase IV (PolIV) enzyme. As part of the RNA-dependent DNA methylation (RdDM) process, PolIV-dependent siRNAs (p4-siRNAs) are loaded onto an ARGONAUTE4-containing complex and guide de novo DNA methyltransferases to target loci. Here we show that the double-stranded RNA binding proteins DRB2 and DRB4 are required for proper accumulation of p4-siRNAs. In flowers, loss of DRB2 results in increased accumulation of p4-siRNAs but not ta-siRNAs, inverted repeat (IR)-derived siRNAs, or miRNA. Loss of DRB2 does not impair uniparental expression of p4-dependent siRNAs in developing endosperm, indicating that p4-siRNA increased accumulation is not the result of the activation of the polIV pathway in the male gametophyte. In contrast to drb2, drb4 mutants exhibit reduced p4-siRNA levels, but the extent of this reduction is variable, according to the nature and size of the p4-siRNAs. Loss of DRB4 also leads to a spectacular increase of p4-independent IR-derived 24-nt siRNAs, suggesting a reallocation of factors from p4-dependent to p4-independent siRNA pathways in drb4. Opposite effects of drb2 and drb4 mutations on the accumulation of p4-siRNAs were also observed in vegetative tissues. Moreover, transgenic plants overexpressing DRB2 mimicked drb4 mutants at the morphological and molecular levels, confirming the antagonistic roles of DRB2 and DRB4.

Dates et versions

hal-01190246 , version 1 (01-09-2015)

Identifiants

Citer

Thierry Pelissier, Marion Clavel, Cristian Chaparro, Marie-Noelle Pouch-Pelissier, Herve Vaucheret, et al.. Double-stranded RNA binding proteins DRB2 and DRB4 have an antagonistic impact on polymerase IV-dependent siRNA levels in Arabidopsis. RNA, 2011, 17 (8), pp.1502 - 1510. ⟨10.1261/rna.2680711⟩. ⟨hal-01190246⟩
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