Analysis of Methylation Status of Plant MicroRNAs.

Small noncoding RNAs of 20-30 nucleotides in length are key mediators of gene silencing. 2'-O-Methylation on the 3' terminal nucleotide of several types of small RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs) in plants, PIWI-interacting RNAs (piRNAs) in animals, and some siRNAs in Drosophila and Caenorhabditis elegans, provides a key protective mechanism against 3' tailing- and trimming-mediated destabilization. The methylation reaction is catalyzed by the small RNA methyltransferase HUA ENHANCER 1 (HEN1). In this chapter, we describe a detailed protocol for analyzing 3' end methylation status of plant miRNAs, which can be applicable to other types of small RNAs as well.