title: A link between RNA metabolism and silencing affecting Arabidopsis development.
abstract: MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are abundant endogenous small RNAs (smRNAs) that control transcript expression through posttranscriptional gene silencing. Here, we show that concomitant loss of XRN4/EIN5, a 5'-3' exoribonuclease, and ABH1/CBP80, a subunit of the mRNA cap binding complex, results in Arabidopsis plants manifesting myriad developmental defects. We find that ABH1/CBP80 is necessary to obtain proper mature miRNA levels, which suggests this protein affects the miRNA-mediated RNA silencing pathway. Additionally, we show that XRN4/EIN5 affects the levels of a smRNA class that is processed from both sense and antisense strands of approximately 130 endogenous transcripts that apparently are converted to double-stranded RNA (dsRNA) and subsequently processed. We find that the parent transcripts of these smRNAs accumulate in an uncapped form upon loss of XRN4/EIN5, which suggests that uncapped endogenous transcripts can become smRNA biogenesis substrates. Overall, our results reveal unexpected connections between RNA metabolism and silencing pathways.
authors.affiliation: Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Gregory
authors.forename: Ronan C
authors.initials: RC
authors.lastname: O'Malley
authors.forename: Ryan
authors.initials: R
authors.lastname: Lister
authors.forename: Mark A
authors.initials: MA
authors.lastname: Urich
authors.forename: Julian
authors.initials: J
authors.lastname: Tonti-Filippini
authors.forename: Huaming
authors.initials: H
authors.lastname: Chen
authors.forename: A Harvey
authors.initials: AH
authors.lastname: Millar
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ecker
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D060565:Argonaute Proteins; D005095:Exoribonucleases / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D017343:Genes, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D039381:RNA Cap-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D018749:RNA, Plant / Q000235:genetics; D034741:RNA, Small Interfering / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D005095:Exoribonucleases; D035683:MicroRNAs; D010940:Plant Proteins; D039381:RNA Cap-Binding Proteins; D018749:RNA, Plant; D034741:RNA, Small Interfering; C435105:At2g13540 protein, Arabidopsis; C117457:AGO1 protein, Arabidopsis; C418137:Xrn1 protein, plant