Novel miR390-dependent transacting siRNA precursors in plants revealed by a PCR-based experimental approach and database analysis.
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 3'-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 5'-terminal miR390 target site.
Krasnikova
M S
MS
Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Timiryazevskaya 42, 127550 Moscow, Russia.
Milyutina
I A
IA
Bobrova
V K
VK
Ozerova
L V
LV
Troitsky
A V
AV
Solovyev
A G
AG
Morozov
S Y
SY
D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D030561:Databases, Nucleic Acid; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D010944:Plants / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012322:RNA Precursors / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014026:Nicotiana / Q000235:genetics; D015533:Transcriptional Activation
D017931:DNA Primers; D018744:DNA, Plant; D035683:MicroRNAs; D012322:RNA Precursors; D018749:RNA, Plant; D034741:RNA, Small Interfering