title: AGO1-miR173 complex initiates phased siRNA formation in plants.
abstract: MicroRNA (miRNA)-guided cleavage initiates entry of primary transcripts into the transacting siRNA (tasiRNA) biogenesis pathway involving RNA-DEPENDENT RNA POLYMERASE6, DICER-LIKE4, and SUPPRESSOR OF GENE SILENCING3. Arabidopsis thaliana TAS1 and TAS2 families yield tasiRNA that form through miR173-guided initiation-cleavage of primary transcripts and target several transcripts encoding pentatricopeptide repeat proteins and proteins of unknown function. Here, the TAS1c locus was modified to produce synthetic (syn) tasiRNA to target an endogenous transcript encoding PHYTOENE DESATURASE and used to analyze the role of miR173 in routing of transcripts through the tasiRNA pathway. miR173 was unique from other miRNAs in its ability to initiate TAS1c-based syn-tasiRNA formation. A single miR173 target site was sufficient to route non-TAS transcripts into the pathway to yield phased siRNA. We also show that miR173 functions in association with ARGONAUTE 1 (AGO1) during TAS1 and TAS2 tasiRNA formation, and we provide data indicating that the miR173-AGO1 complex possesses unique functionality that many other miRNA-AGO1 complexes lack.
authors.affiliation: Molecular and Cellular Biology Program, Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Taiowa A
authors.initials: TA
authors.lastname: Montgomery
authors.forename: Seong Jeon
authors.initials: SJ
authors.lastname: Yoo
authors.forename: Noah
authors.initials: N
authors.lastname: Fahlgren
authors.forename: Sunny D
authors.initials: SD
authors.lastname: Gilbert
authors.forename: Miya D
authors.initials: MD
authors.lastname: Howell
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Sullivan
authors.forename: Amanda
authors.initials: A
authors.lastname: Alexander
authors.forename: Goretti
authors.initials: G
authors.lastname: Nguyen
authors.forename: Edwards
authors.initials: E
authors.lastname: Allen
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Ahn
authors.forename: James C
authors.initials: JC
authors.lastname: Carrington
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D060565:Argonaute Proteins; D035683:MicroRNAs / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger; D018749:RNA, Plant / Q000096:biosynthesis*; D034741:RNA, Small Interfering / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: C117457:AGO1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; C534587:MIRN173 microRNA, Arabidopsis; D035683:MicroRNAs; D012333:RNA, Messenger; D018749:RNA, Plant; D034741:RNA, Small Interfering