title: Discrete small RNA-generating loci as master regulators of transposon activity in Drosophila.
abstract: Drosophila Piwi-family proteins have been implicated in transposon control. Here, we examine piwi-interacting RNAs (piRNAs) associated with each Drosophila Piwi protein and find that Piwi and Aubergine bind RNAs that are predominantly antisense to transposons, whereas Ago3 complexes contain predominantly sense piRNAs. As in mammals, the majority of Drosophila piRNAs are derived from discrete genomic loci. These loci comprise mainly defective transposon sequences, and some have previously been identified as master regulators of transposon activity. Our data suggest that heterochromatic piRNA loci interact with potentially active, euchromatic transposons to form an adaptive system for transposon control. Complementary relationships between sense and antisense piRNA populations suggest an amplification loop wherein each piRNA-directed cleavage event generates the 5' end of a new piRNA. Thus, sense piRNAs, formed following cleavage of transposon mRNAs may enhance production of antisense piRNAs, complementary to active elements, by directing cleavage of transcripts from master control loci.
authors.affiliation: Cold Spring Harbor Laboratory, Watson School of Biological Sciences and Howard Hughes Medical Institute, Cold Spring Harbor, NY 11724, USA.
authors.forename: Julius
authors.initials: J
authors.lastname: Brennecke
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Aravin
authors.forename: Alexander
authors.initials: A
authors.lastname: Stark
authors.forename: Monica
authors.initials: M
authors.lastname: Dus
authors.forename: Manolis
authors.initials: M
authors.lastname: Kellis
authors.forename: Ravi
authors.initials: R
authors.lastname: Sachidanandam
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Hannon
mesh_terms: D000818:Animals; D060565:Argonaute Proteins; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D049750:Genome, Insect; D008297:Male; D008969:Molecular Sequence Data; D005810:Multigene Family; D010053:Ovary / Q000737:chemistry; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D034743:RNA-Induced Silencing Complex; D011994:Recombinant Proteins / Q000235:genetics; D018626:Retroelements; D014157:Transcription Factors / Q000235:genetics
chemical_list: C518392:AGO3 protein, Drosophila; D060565:Argonaute Proteins; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D010448:Peptide Initiation Factors; D011506:Proteins; D016372:RNA, Antisense; D016601:RNA-Binding Proteins; D034743:RNA-Induced Silencing Complex; D011994:Recombinant Proteins; D018626:Retroelements; D014157:Transcription Factors; C436124:aub protein, Drosophila; C110987:mdg4 protein (gypsy); C116498:piwi protein, Drosophila; D012313:RNA