title: Identification and Functional Analysis of the Pre-piRNA 3' Trimmer in Silkworms.
abstract: PIWI-interacting RNAs (piRNAs) play a crucial role in transposon silencing in animal germ cells. In piRNA biogenesis, single-stranded piRNA intermediates are loaded into PIWI-clade proteins and cleaved by Zucchini/MitoPLD, yielding precursor piRNAs (pre-piRNAs). Pre-piRNAs that are longer than the mature piRNA length are then trimmed at their 3' ends. Although recent studies implicated the Tudor domain protein Papi/Tdrkh in pre-piRNA trimming, the identity of Trimmer and its relationship with Papi/Tdrkh remain unknown. Here, we identified PNLDC1, an uncharacterized 3'-5' exonuclease, as Trimmer in silkworms. Trimmer is enriched in the mitochondrial fraction and binds to Papi/Tdrkh. Depletion of Trimmer and Papi/Tdrkh additively inhibits trimming, causing accumulation of ∼35-40-nt pre-piRNAs that are impaired for target cleavage and prone to degradation. Our results highlight the cooperative action of Trimmer and Papi/Tdrkh in piRNA maturation.
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Izumi
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Shoji
authors.affiliation: Department of Chemistry and Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Sakaguchi
authors.affiliation: Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Shozo
authors.initials: S
authors.lastname: Honda
authors.affiliation: Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kirino
authors.affiliation: Department of Chemistry and Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Katsuma
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan. Electronic address: tomari@iam.u-tokyo.ac.jp.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Tomari
mesh_terms: D000818:Animals; D012831:Bombyx / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D034741:RNA, Small Interfering / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins