PMID:16449203

Citation	Yang, Z, Ebright, YW, Yu, B and Chen, X (2006) HEN1 recognizes 21-24 nt small RNA duplexes and deposits a methyl group onto the 2' OH of the 3' terminal nucleotide. Nucleic Acids Res. 34:667-75
Abstract	microRNAs (miRNAs) and small interfering RNAs (siRNAs) in plants bear a methyl group on the ribose of the 3' terminal nucleotide. We showed previously that the methylation of miRNAs and siRNAs requires the protein HEN1 in vivo and that purified HEN1 protein methylates miRNA/miRNA* duplexes in vitro. In this study, we show that HEN1 methylates both miRNA/miRNA* and siRNA/siRNA* duplexes in vitro with a preference for 21-24 nt RNA duplexes with 2 nt overhangs. We also demonstrate that HEN1 deposits the methyl group on to the 2' OH of the 3' terminal nucleotide. Among various modifications that can occur on the ribose of the terminal nucleotide, such as 2'-deoxy, 3'-deoxy, 2'-O-methyl and 3'-O-methyl, only 2'-O-methyl on a small RNA inhibits the activity of yeast poly(A) polymerase (PAP). These findings indicate that HEN1 specifically methylates miRNAs and siRNAs and implicate the importance of the 2'-O-methyl group in the biology of RNA silencing.
Links	PubMed PMC1356533 Online version:10.1093/nar/gkj474
Keywords	Escherichia coli Proteins/metabolism; Methylation; Methyltransferases/metabolism; MicroRNAs/metabolism; Nucleotides/chemistry; Polynucleotide Adenylyltransferase/chemistry; RNA, Double-Stranded/chemistry; RNA, Double-Stranded/metabolism; RNA, Small Interfering/chemistry; RNA, Small Interfering/metabolism; Substrate Specificity; Yeasts/enzymology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ARATH:HEN1		GO:0061715: miRNA 2'-O-methylation	ECO:0000314:		P		Figures 1 and 2 show that HEN1 methylates miRNA duplexes. Figure 3 shows that the position of methylation is the 2’OH of the 3’ terminal nucleotide.	complete CACAO 12210

References

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