microRNA-Directed Phasing during Trans-Acting siRNA Biogenesis in Plants

Plants and animals use small RNAs (microRNAs [miRNAs] and siRNAs) as guides for posttranscriptional and epigenetic regulation. In plants, miRNAs and trans-acting (ta) siRNAs form through distinct biogenesis pathways, although they both interact with target transcripts and guide cleavage. An integrat...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Cell 2005-04, Vol.121 (2), p.207-221
Hauptverfasser: Allen, Edwards, Xie, Zhixin, Gustafson, Adam M., Carrington, James C.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Plants and animals use small RNAs (microRNAs [miRNAs] and siRNAs) as guides for posttranscriptional and epigenetic regulation. In plants, miRNAs and trans-acting (ta) siRNAs form through distinct biogenesis pathways, although they both interact with target transcripts and guide cleavage. An integrated approach to identify targets of Arabidopsis thaliana miRNAs and ta-siRNAs revealed several new classes of small RNA-regulated genes, including conventional genes such as Argonaute2 and an E2-ubiquitin conjugating enzyme. Surprisingly, five ta-siRNA-generating transcripts were identified as targets of miR173 or miR390. Rather than functioning as negative regulators, miR173- and miR390-guided cleavage was shown to set the 21-nucleotide phase for ta-siRNA precursor processing. These data support a model in which miRNA-guided formation of a 5′ or 3′ terminus within pre-ta-siRNA transcripts, followed by RDR6-dependent formation of dsRNA and Dicer-like processing, yields phased ta-siRNAs that negatively regulate other genes.
ISSN:0092-8674
1097-4172
DOI:10.1016/j.cell.2005.04.004