"siRNAs compete with miRNAs for methylation by HEN1 in Arabidopsis."

Yu B, Bi L, Zhai J, Agarwal M, Li S, Wu Q, Ding SW, Meyers BC, Vaucheret H, Chen X



Published 2010-09-01 in Nucleic Acids Res volume 38 .

Pubmed ID: 20448024
DOI identifier: -

Abstract:
Plant microRNAs (miRNAs) and small interfering RNAs (siRNAs) bear a 2'-O-methyl group on the 3'-terminal nucleotide. This methyl group is post-synthetically added by the methyltransferase protein HEN1 and protects small RNAs from enzymatic activities that target the 3'-OH. A mutagenesis screen for suppressors of the partial loss-of-function hen1-2 allele in Arabidopsis identified second-site mutations that restore miRNA methylation. These mutations affect two subunits of the DNA-dependent RNA polymerase IV (Pol IV), which is essential for the biogenesis of 24 nt endogenous siRNAs. A mutation in RNA-dependent RNA polymerase 2, another essential gene for the biogenesis of endogenous 24-nt siRNAs, also rescued the defects in miRNA methylation of hen1-2, revealing a previously unsuspected, negative influence of siRNAs on HEN1-mediated miRNA methylation. In addition, our findings imply the existence of a negative modifier of HEN1 activity in the Columbia genetic background.


This publication refers to following proteins:



Last modification of this entry: Sept. 6, 2012