title: Piwi is required in multiple cell types to control germline stem cell lineage development in the Drosophila ovary.
abstract: The piRNA pathway plays an important role in maintaining genome stability in the germ line by silencing transposable elements (TEs) from fly to mammals. As a highly conserved piRNA pathway component, Piwi is widely expressed in both germ cells and somatic cells in the Drosophila ovary and is required for piRNA production in both cell types. In addition to its known role in somatic cap cells to maintain germline stem cells (GSCs), this study has demonstrated that Piwi has novel functions in somatic cells and germ cells of the Drosophila ovary to promote germ cell differentiation. Piwi knockdown in escort cells causes a reduction in escort cell (EC) number and accumulation of undifferentiated germ cells, some of which show active BMP signaling, indicating that Piwi is required to maintain ECs and promote germ cell differentiation. Simultaneous knockdown of dpp, encoding a BMP, in ECs can partially rescue the germ cell differentiation defect, indicating that Piwi is required in ECs to repress dpp. Consistent with its key role in piRNA production, TE transcripts increase significantly and DNA damage is also elevated in the piwi knockdown somatic cells. Germ cell-specific knockdown of piwi surprisingly causes depletion of germ cells before adulthood, suggesting that Piwi might control primordial germ cell maintenance or GSC establishment. Finally, Piwi inactivation in the germ line of the adult ovary leads to gradual GSC loss and germ cell differentiation defects, indicating the intrinsic role of Piwi in adult GSC maintenance and differentiation. This study has revealed new germline requirement of Piwi in controlling GSC maintenance and lineage differentiation as well as its new somatic function in promoting germ cell differentiation. Therefore, Piwi is required in multiple cell types to control GSC lineage development in the Drosophila ovary.
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America; Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, United States of America.
authors.forename: Xing
authors.initials: X
authors.lastname: Ma
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America; Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, United States of America.
authors.forename: Su
authors.initials: S
authors.lastname: Wang
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Trieu
authors.initials: T
authors.lastname: Do
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Song
authors.affiliation: Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Mayu
authors.initials: M
authors.lastname: Inaba
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Nishimoto
authors.affiliation: School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Lu-ping
authors.initials: LP
authors.lastname: Liu
authors.affiliation: School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Mao
authors.affiliation: School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: William
authors.initials: W
authors.lastname: McDowell
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Jungeun
authors.initials: J
authors.lastname: Park
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Kate
authors.initials: K
authors.lastname: Malanowski
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Allison
authors.initials: A
authors.lastname: Peak
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Anoja
authors.initials: A
authors.lastname: Perera
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Karin
authors.initials: K
authors.lastname: Gaudenz
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America.
authors.forename: Jeff
authors.initials: J
authors.lastname: Haug
authors.affiliation: Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Yamashita
authors.affiliation: Yale Stem Cell Center, Yale University School of Medicine, New Haven, Connecticut, United Sates of America.
authors.forename: Haifan
authors.initials: H
authors.lastname: Lin
authors.affiliation: School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Jian-quan
authors.initials: JQ
authors.lastname: Ni
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri, United States of America; Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, United States of America.
authors.forename: Ting
authors.initials: T
authors.lastname: Xie
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation; D019070:Cell Lineage; D004249:DNA Damage; D004330:Drosophila / Q000166:cytology / Q000196:embryology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005260:Female; D010053:Ovary / Q000166:cytology* / Q000196:embryology; D015398:Signal Transduction
chemical_list: D060565:Argonaute Proteins; D029721:Drosophila Proteins; C116498:piwi protein, Drosophila