title: A MicroRNA precursor surveillance system in quality control of MicroRNA synthesis.
abstract: MicroRNAs (miRNAs) are essential for regulation of gene expression. Though numerous miRNAs have been identified by high-throughput sequencing, few precursor miRNAs (pre-miRNAs) are experimentally validated. Here we report a strategy for constructing high-throughput sequencing libraries enriched for full-length pre-miRNAs. We find widespread and extensive uridylation of Argonaute (Ago)-bound pre-miRNAs, which is primarily catalyzed by two terminal uridylyltransferases: TUT7 and TUT4. Uridylation by TUT7/4 not only polishes pre-miRNA 3' ends, but also facilitates their degradation by the exosome, preventing clogging of Ago with defective species. We show that the exosome exploits distinct substrate preferences of DIS3 and RRP6, its two catalytic subunits, to distinguish productive from defective pre-miRNAs. Furthermore, we identify a positive feedback loop formed by the exosome and TUT7/4 in triggering uridylation and degradation of Ago-bound pre-miRNAs. Our study reveals a pre-miRNA surveillance system that comprises TUT7, TUT4, and the exosome in quality control of miRNA synthesis.
authors.affiliation: Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Xuhang
authors.initials: X
authors.lastname: Liu
authors.affiliation: PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Vrettos
authors.affiliation: Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Manolis
authors.initials: M
authors.lastname: Maragkakis
authors.affiliation: Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Alexiou
authors.affiliation: PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Gregory
authors.affiliation: Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; PENN Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: mourelaz@uphs.upenn.edu.
authors.forename: Zissimos
authors.initials: Z
authors.lastname: Mourelatos
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D063326:Exosome Multienzyme Ribonuclease Complex / Q000737:chemistry / Q000378:metabolism*; D055354:Exosomes / Q000378:metabolism; D016678:Genome; D057809:HEK293 Cells; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D012316:RNA Nucleotidyltransferases / Q000378:metabolism; D014529:Uridine / Q000378:metabolism*
chemical_list: D060565:Argonaute Proteins; D035683:MicroRNAs; D012316:RNA Nucleotidyltransferases; D063326:Exosome Multienzyme Ribonuclease Complex; D014529:Uridine