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Journal of Biomedicine and Biotechnology
Volume 2009, Article ID 952304, 9 pages
http://dx.doi.org/10.1155/2009/952304
Research Article

Novel miR390-Dependent Transacting siRNA Precursors in Plants Revealed by a PCR-Based Experimental Approach and Database Analysis

1Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Timiryazevskaya 42, 127550 Moscow, Russia
2A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
3Main Botanic Garden Russian Academy of Sciences, Botanicheskaya 4, 127276 Moscow, Russia

Received 28 February 2009; Accepted 31 July 2009

Academic Editor: Zhumur Ghosh

Copyright © 2009 M. S. Krasnikova et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

TAS loci in plant genomes encode transacting small interfering RNAs (ta-siRNAs) that regulate expression of a number of genes. The function of TAS3 precursor in Arabidopsis thaliana is controlled by two miR390 target sites flanking two ta-siARF sequences targeting mRNAs of ARF transcription factors. Cleavage of the -miR390-site initiates ta-siRNAs biogenesis. Here we describe the new method for identification of plant ta-siRNA precursors based on PCR with oligodeoxyribonucleotide primers mimicking miR390. The method was found to be efficient for dicotiledonous plants, cycads, and mosses. Based on sequences of amplified loci and a database analysis, a novel type of miR390-dependent TAS sequences was identified in dicots. These TAS loci are characterized by a smaller distance between miR390 sites compared to TAS3, a single copy of ta-siARF, and a sequence conservation pattern pointing to the possibility that processing of novel TAS-like locus is initiated by cleavage of the -terminal miR390 target site.