title: RNA clamping by Vasa assembles a piRNA amplifier complex on transposon transcripts.
abstract: Germline-specific Piwi-interacting RNAs (piRNAs) protect animal genomes against transposons and are essential for fertility. piRNAs targeting active transposons are amplified by the ping-pong cycle, which couples Piwi endonucleolytic slicing of target RNAs to biogenesis of new piRNAs. Here, we describe the identification of a transient Amplifier complex that mediates biogenesis of secondary piRNAs in insect cells. Amplifier is nucleated by the DEAD box RNA helicase Vasa and contains the two Piwi proteins participating in the ping-pong loop, the Tudor protein Qin/Kumo and antisense piRNA guides. These components assemble on the surface of Vasa's helicase domain, which functions as an RNA clamp to anchor Amplifier onto transposon transcripts. We show that ATP-dependent RNP remodeling by Vasa facilitates transfer of 5' sliced piRNA precursors between ping-pong partners, and loss of this activity causes sterility in Drosophila. Our results reveal the molecular basis for the small RNA amplification that confers adaptive immunity against transposons.
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Jordi
authors.initials: J
authors.lastname: Xiol
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Pietro
authors.initials: P
authors.lastname: Spinelli
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany.
authors.forename: Maike A
authors.initials: MA
authors.lastname: Laussmann
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, 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, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Zhaolin
authors.initials: Z
authors.lastname: Yang
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Cora
authors.affiliation: Laboratoire Biologie à Grande Echelle, IRTSV, CEA, 38054 Grenoble, France.
authors.forename: Yohann
authors.initials: Y
authors.lastname: Couté
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Conn
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Jan
authors.initials: J
authors.lastname: Kadlec
authors.affiliation: Department of Oncological Sciences, Icahn School of Medicine at Sinai, New York, NY 10029, USA.
authors.forename: Ravi
authors.initials: R
authors.lastname: Sachidanandam
authors.affiliation: Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Kaksonen
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France.
authors.forename: Stephen
authors.initials: S
authors.lastname: Cusack
authors.affiliation: Developmental Biology Unit, EMBL, 69117 Heidelberg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Ephrussi
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France; Unit for Virus Host-Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 71 avenue des Martyrs, 38042, France. Electronic address: pillai@embl.fr.
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Pillai
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D004251:DNA Transposable Elements; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*
chemical_list: D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D019476:Insect Proteins; D034741:RNA, Small Interfering; D000255:Adenosine Triphosphate; C088269:vas protein, Drosophila; D053487:DEAD-box RNA Helicases