title: PIWI Slicing and RNA Elements in Precursors Instruct Directional Primary piRNA Biogenesis.
abstract: PIWI proteins and PIWI-interacting RNAs (piRNAs) mediate repression of transposons in the animal gonads. Primary processing converts long single-stranded RNAs into ∼30-nt piRNAs, but their entry into the biogenesis pathway is unknown. Here, we demonstrate that an RNA element at the 5' end of a piRNA cluster—which we termed piRNA trigger sequence (PTS)—can induce primary processing of any downstream sequence. We propose that such signals are triggers for the generation of the original pool of piRNAs. We also demonstrate that endonucleolytic cleavage of a transcript by a cytosolic PIWI results in its entry into primary processing, which triggers the generation of non-overlapping, contiguous primary piRNAs in the 3' direction from the target transcript. These piRNAs are loaded into a nuclear PIWI, thereby linking cytoplasmic post-transcriptional silencing to nuclear transcriptional repression.
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France.
authors.forename: David
authors.initials: D
authors.lastname: Homolka
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France.
authors.forename: Radha Raman
authors.initials: RR
authors.lastname: Pandey
authors.affiliation: Clermont Université, Université d'Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
authors.forename: Coline
authors.initials: C
authors.lastname: Goriaux
authors.affiliation: Clermont Université, Université d'Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Brasset
authors.affiliation: Clermont Université, Université d'Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Vaury
authors.affiliation: Department of Oncological Sciences, Icahn School of Medicine at Sinai, One Gustave L. Levy Place, New York, NY 10029, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Sachidanandam
authors.affiliation: iRTSV, CEA-Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9, France.
authors.forename: Marie-Odile
authors.initials: MO
authors.lastname: Fauvarque
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France. Electronic address: pillai@embl.fr.
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Pillai
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D020868:Gene Silencing; D020033:Protein Isoforms; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*
chemical_list: D060565:Argonaute Proteins; D029721:Drosophila Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; C116498:piwi protein, Drosophila