Open AccesssiRNAs compete with miRNAs for methylation by HEN1 in Arabidopsis
Author(s) -
Bin Yu,
Lei Bi,
Jixian Zhai,
Manu Agarwal,
Shengben Li,
Qingfa Wu,
ShouWei Ding,
Blake C. Meyers,
Hervé Vaucheret,
Xuemei Chen
Publication year - 2010
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/gkq348
Subject(s) - biology , trans acting sirna , small interfering rna , rna , small rna , genetics , methylation , rna directed dna methylation , microrna , dna methylation , microbiology and biotechnology , gene , gene expression
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.