title: Inheritance of a Nuclear PIWI from Pluripotent Stem Cells by Somatic Descendants Ensures Differentiation by Silencing Transposons in Planarian.
abstract: Differentiation of pluripotent stem cells (PSCs) requires transposon silencing throughout the process. PIWIs, best known as key factors in germline transposon silencing, are also known to act in somatic differentiation of planarian PSCs (neoblasts). However, how PIWIs control the latter process remains elusive. Here, using Dugesia japonica, we show that a nuclear PIWI, DjPiwiB, was bound to PIWI-interacting RNAs (generally key mediators of PIWI-dependent transposon silencing), and was detected in not only neoblasts but also their descendant somatic cells, which do not express piwi. In contrast, cytoplasmic DjPiwiA and DjPiwiC were detected only in neoblasts, in accord with their transcription there. DjPiwiB was indispensable for regeneration, but dispensable for transposon silencing in neoblasts. However, transposons were derepressed at the onset of differentiation in DjPiwiB-knockdown planarians. Thus, DjPiwiB appears to be inherited by descendant somatic cells of neoblasts to ensure transposon silencing in those cells, which are unable to produce PIWI proteins.
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan. Electronic address: shiba@mdb.biophys.kyoto-u.ac.jp.
authors.forename: Norito
authors.initials: N
authors.lastname: Shibata
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kashima
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Ishiko
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan; Center for Life Science Technologies, RIKEN, 2-2-3, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishimura
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Labib
authors.initials: L
authors.lastname: Rouhana
authors.affiliation: Center for Life Science Technologies, RIKEN, 2-2-3, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Misaki
authors.affiliation: Center for Life Science Technologies, RIKEN, 2-2-3, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yonemura
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, 3 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, 3 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Siomi
authors.affiliation: Department of Molecular Biology, Keio University School of Medicine, 3 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Mikiko C
authors.initials: MC
authors.lastname: Siomi
authors.affiliation: Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan. Electronic address: agata@mdb.biophys.kyoto-u.ac.jp.
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Agata
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D001483:Base Sequence; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism*; D004251:DNA Transposable Elements / Q000235:genetics*; D020868:Gene Silencing; D007150:Immunohistochemistry; D040582:Inheritance Patterns / Q000235:genetics*; D008954:Models, Biological; D010932:Planarians / Q000166:cytology* / Q000235:genetics*; D039904:Pluripotent Stem Cells / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D060565:Argonaute Proteins; D004251:DNA Transposable Elements; D034741:RNA, Small Interfering