title: Approaches for studying microRNA and small interfering RNA methylation in vitro and in vivo.
abstract: The biogenesis of microRNAs (miRNAs) in plants is similar to that in animals, however, the processing of plant miRNAs consists of an additional step, the methylation of the miRNAs on the 3' terminal nucleotides. The enzyme that methylates Arabidopsis miRNAs is encoded by a gene named HEN1, which has been shown genetically to be required for miRNA biogenesis in vivo. Small interfering RNAs (siRNAs) are also methylated in vivo in a HEN1-dependent manner. Our biochemical studies demonstrated that HEN1 is a methyltransferase acting on both miRNAs and siRNAs in vitro. HEN1 recognizes 21 to 24 nt small RNA duplexes, which are the products of Dicer-like enzymes, and transfers a methyl group from S-adenosylmethionine (SAM) to the 2' OH of the last nucleotides of the small RNA duplexes. Here we describe methods to characterize the biochemical activities of the HEN1 protein both in vitro and in vivo, and methods to analyze the methylation status of small RNAs in vivo.
authors.affiliation: Department of Botany and Plant Sciences and Institute of Integrative Genome Biology, University of California-Riverside, Riverside, California, USA.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Yang
authors.forename: Giedrius
authors.initials: G
authors.lastname: Vilkaitis
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.forename: Saulius
authors.initials: S
authors.lastname: Klimasauskas
authors.forename: Xuemei
authors.initials: X
authors.lastname: Chen
mesh_terms: D015152:Blotting, Northern; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D047468:Immunoprecipitation; D008745:Methylation; D008780:Methyltransferases; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D035683:MicroRNAs; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C507832:HEN1 protein , Escherichia coli; D008780:Methyltransferases