title: Deep-sequencing of human Argonaute-associated small RNAs provides insight into miRNA sorting and reveals Argonaute association with RNA fragments of diverse origin.
abstract: While several studies have focused on the relationship between individual miRNA loci or classes of small RNA with human Argonaute (AGO) proteins, a comprehensive, global analysis of the RNA content associating with different AGO proteins has yet to be performed. We have compared the content of deep sequenced RNA extracted from immunoprecipitation experiments with the AGO1, AGO2, and AGO3 proteins. Consistent with previous observations, sequence tags derived from miRNA loci globally associate in approximately equivalent amounts with AGO1, AGO2, and AGO3. Exceptions include miR-182, miR-222, and miR-223*, which could be coupled to processes targeting the loci for interaction with specific AGO proteins. A closer inspection of the data, however, supports the presence of an unusual sorting mechanism wherein a subset of miRNA loci give rise to distinct isomirs which preferentially associate with distinct AGO proteins in a significantly differential manner. We also identify the complete set of short RNA derived from non-miRNA sources including tRNA, snRNA, snoRNA, vRNA, and mRNA associating with the AGO proteins, many of which are predicted to play roles in post-transcriptional gene silencing. We also observe enrichment of tags mapping to promoter regions of genes, suggesting that a fraction of the recently-identified promoter-associated small RNAs in humans could function through interaction with AGO proteins. Finally, we observe antisense miRNA transcripts are frequently present in low copy numbers across a range of diverse miRNA loci and these transcripts appear to associate with AGO proteins.
authors.affiliation: Omics Science Center, RIKEN Yokohama Institute, Yokohama-shi, Kanagawa, Japan. burrough@gsc.riken.jp
authors.forename: Alexander Maxwell
authors.initials: AM
authors.lastname: Burroughs
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Ando
authors.forename: Michiel Jan Laurens
authors.initials: MJ
authors.lastname: de Hoon
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tomaru
authors.forename: Harukazu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Hayashizaki
authors.forename: Carsten Olivier
authors.initials: CO
authors.lastname: Daub
mesh_terms: D060565:Argonaute Proteins; D001483:Base Sequence; D002874:Chromosome Mapping; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000235:genetics* / Q000378:metabolism; D015723:Gene Library; D056426:Genetic Loci; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D034622:RNA Interference; D034443:RNA Transport; D012333:RNA, Messenger / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D043244:Ribonuclease III / Q000378:metabolism; D017423:Sequence Analysis, RNA
chemical_list: C115848:AGO1 protein, human; C466422:AGO2 protein, human; C517143:AGO3 protein, human; D060565:Argonaute Proteins; D015852:Eukaryotic Initiation Factor-2; D039642:Eukaryotic Initiation Factors; D035683:MicroRNAs; D012333:RNA, Messenger; D012343:RNA, Transfer; C408087:DICER1 protein, human; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases