title: MicroRNA-dependent trans-acting siRNA production.
abstract: Less than a year has elapsed between the discovery of trans-acting small interfering RNAs (tasiRNAs) in plants and the elucidation of the major steps of the corresponding pathway. During tasiRNA biogenesis, polyadenylated RNAs transcribed from non-protein-coding TAS genes are cleaved by a microRNA (miRNA)-programmed RNA-induced silencing complex. In contrast to classical miRNA targets, RDR6 and SGS3 convert one of the TAS RNA cleavage products into double-stranded RNA, which is subsequently processed, in a phase determined by the initial miRNA cleavage site, by DICER-LIKE 4 to generate a 21-nucleotide tasiRNA population. tasiRNAs guide endogenous mRNA cleavage through the action of AGO1 or, perhaps in some cases, AGO7. Some of the tasiRNA targets probably regulate the juvenile-to-adult phase transition, but the roles of other tasiRNA targets remain to be determined.
authors.affiliation: Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA 78026 Versailles Cedex, France. herve.vaucheret@versailles.inra.fr
authors.forename: Hervé
authors.initials: H
authors.lastname: Vaucheret
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D035683:MicroRNAs / Q000502:physiology*; D008957:Models, Genetic; D012323:RNA Processing, Post-Transcriptional; D018749:RNA, Plant / Q000502:physiology*; D034741:RNA, Small Interfering / Q000096:biosynthesis*
chemical_list: D029681:Arabidopsis Proteins; D035683:MicroRNAs; D018749:RNA, Plant; D034741:RNA, Small Interfering