title: piwi encodes a nucleoplasmic factor whose activity modulates the number and division rate of germline stem cells.
abstract: piwi represents the first class of genes known to be required for stem cell self-renewal in diverse organisms. In the Drosophila ovary, piwi is required in somatic signaling cells to maintain germline stem cells. Here we show that piwi encodes a novel nucleoplasmic protein present in both somatic and germline cells, with the highly conserved C-terminal region essential for its function. Removing PIWI protein from single germline stem cells significantly decreases the rate of their division. This suggests that PIWI has a second role as a cell-autonomous promoter of germline stem cell division. Consistent with its dual function, over-expression of piwi in somatic cells causes an increase both in the number of germline stem cells and the rate of their division. Thus, PIWI is a key regulator of stem cell division - its somatic expression modulates the number of germline stem cells and the rate of their division, while its germline expression also contributes to promoting stem cell division in a cell-autonomous manner.
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Cox
authors.forename: A
authors.initials: A
authors.lastname: Chao
authors.forename: H
authors.initials: H
authors.lastname: Lin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D060565:Argonaute Proteins; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D005260:Female; D016259:Genes, myc; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology; D008297:Male; D016366:Open Reading Frames; D010053:Ovary / Q000166:cytology / Q000502:physiology; D010063:Ovum / Q000166:cytology* / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D034743:RNA-Induced Silencing Complex; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology
chemical_list: D060565:Argonaute Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D011506:Proteins; D034743:RNA-Induced Silencing Complex; D011993:Recombinant Fusion Proteins; C116498:piwi protein, Drosophila