title: Krimper Enforces an Antisense Bias on piRNA Pools by Binding AGO3 in the Drosophila Germline.
abstract: Piwi-interacting RNAs (piRNAs) suppress transposon activity in animal germ cells. In the Drosophila ovary, primary Aubergine (Aub)-bound antisense piRNAs initiate the ping-pong cycle to produce secondary AGO3-bound sense piRNAs. This increases the number of secondary Aub-bound antisense piRNAs that can act to destroy transposon mRNAs. Here we show that Krimper (Krimp), a Tudor-domain protein, directly interacts with piRNA-free AGO3 to promote symmetrical dimethylarginine (sDMA) modification, ensuring sense piRNA-loading onto sDMA-modified AGO3. In aub mutant ovaries, AGO3 associates with ping-pong signature piRNAs, suggesting AGO3's compatibility with primary piRNA loading. Krimp sequesters ectopically expressed AGO3 within Krimp bodies in cultured ovarian somatic cells (OSCs), in which only the primary piRNA pathway operates. Upon krimp-RNAi in OSCs, AGO3 loads with piRNAs, further showing the capacity of AGO3 for primary piRNA loading. We propose that Krimp enforces an antisense bias on piRNA pools by binding AGO3 and blocking its access to primary piRNAs.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: Yuka W
authors.initials: YW
authors.lastname: Iwasaki
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: Aoi
authors.initials: A
authors.lastname: Shibuya
authors.affiliation: RIKEN Center for Life Science Technologies, Division of Genomic Technologies, RIKEN Yokohama Campus, Yokohama 230-0045, Japan.
authors.forename: Piero
authors.initials: P
authors.lastname: Carninci
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Yuuta
authors.initials: Y
authors.lastname: Tsuchizawa
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ishizu
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan. Electronic address: siomim@bs.s.u-tokyo.ac.jp.
authors.forename: Mikiko C
authors.initials: MC
authors.lastname: Siomi
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan. Electronic address: awa403@keio.jp.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Siomi
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism* / Q000502:physiology*; D004331:Drosophila melanogaster; D005260:Female; D008745:Methylation; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*
chemical_list: C518392:AGO3 protein, Drosophila; D060565:Argonaute Proteins; D029721:Drosophila Proteins; C000602673:Krimp protein, Drosophila; D034741:RNA, Small Interfering