title: Transgenically expressed viral RNA silencing suppressors interfere with microRNA methylation in Arabidopsis.
abstract: HEN1-dependent methylation of the 3'-terminal nucleotide is a crucial step in plant microRNA (miRNA) biogenesis. Here we report that several viral RNA silencing suppressors (P1/HC-Pro, p21 and p19) inhibit miRNA methylation. These suppressors have distinct effects on different miRNAs. We also show that miRNA* is methylated in vivo in a suppressor-sensitive manner, suggesting that the viral proteins interfere with miRNA/miRNA* duplexes. p19 and p21 bind both methylated and unmethylated miRNA/miRNA* duplexes in vivo. These findings suggest miRNA/miRNA* as the in vivo substrates for the HEN1 miRNA methyltransferase and raise intriguing possibilities regarding the cellular location of miRNA methylation.
authors: Department of Botany and Plant Sciences and Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
authors: Bin
authors: B
authors: Yu
authors: Elisabeth J
authors: EJ
authors: Chapman
authors: Zhiyong
authors: Z
authors: Yang
authors: James C
authors: JC
authors: Carrington
authors: Xuemei
authors: X
authors: Chen