title: Profiles of piRNA abundances at emerging or established piRNA loci are determined by local DNA sequences.
abstract: Piwi-interacting RNAs (piRNAs) ensure transposable element silencing in Drosophila, thereby preserving genome integrity across generations. Primary piRNAs arise from the processing of long RNA transcripts produced in the germ line by a limited number of telomeric and pericentromeric loci. Primary piRNAs bound to the Argonaute protein Aubergine then drive the production of secondary piRNAs through the "ping-pong" amplification mechanism that involves an interplay with piRNAs bound to the Argonaute protein Argonaute-3. We recently discovered that clusters of P-element-derived transgenes produce piRNAs and mediate silencing of homologous target transgenes in the female germ line. We also demonstrated that some clusters are able to convert other homologous inactive transgene clusters into piRNA-producing loci, which then transmit their acquired silencing capacity over generations. This paramutation phenomenon is mediated by maternal inheritance of piRNAs homologous to the transgenes. Here we further mined our piRNA sequencing data sets generated from various strains carrying transgenes with partial sequence homology at distinct genomic sites. This analysis revealed that same sequences in different genomic contexts generate highly similar profiles of piRNA abundances. The strong tendency of piRNAs for bearing a U at their 5' end has long been recognized. Our observations support the notion that, in addition, the relative frequencies of Drosophila piRNAs are locally determined by the DNA sequence of piRNA loci.
authors.affiliation: Epigenetic Repression and Transposable Elements; Laboratoire Biologie du Développement; UMR7622; CNRS-Université Pierre et Marie Curie; Paris, France.
authors.forename: Augustin
authors.initials: A
authors.lastname: de Vanssay
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Bougé
authors.forename: Antoine
authors.initials: A
authors.lastname: Boivin
authors.forename: Catherine
authors.initials: C
authors.lastname: Hermant
authors.forename: Laure
authors.initials: L
authors.lastname: Teysset
authors.forename: Valérie
authors.initials: V
authors.lastname: Delmarre
authors.forename: Stéphane
authors.initials: S
authors.lastname: Ronsseray
authors.forename: Christophe
authors.initials: C
authors.lastname: Antoniewski
mesh_terms: D000818:Animals; D060565:Argonaute Proteins; D001483:Base Sequence; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020868:Gene Silencing; D056426:Genetic Loci; D005854:Germ Cells; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017423:Sequence Analysis, RNA; D012689:Sequence Homology, Nucleic Acid; D019076:Transgenes; D014529:Uridine / Q000378:metabolism
chemical_list: D060565:Argonaute Proteins; D034741:RNA, Small Interfering; D014529:Uridine
keywords: Drosophila melanogaster; argonaute proteins; epigenetics; germline; paramutation; piRNA biogenesis; transposable elements