title: A novel class of evolutionarily conserved genes defined by piwi are essential for stem cell self-renewal.
abstract: Germ-line stem cells (GSCs) serve as the source for gametogenesis in diverse organisms. We cloned and characterized the Drosophila piwi gene and showed that it is required for the asymmetric division of GSCs to produce and maintain a daughter GSC but is not essential for the further differentiation of the committed daughter cell. Genetic mosaic and RNA in situ analyses suggest that piwi expression in adjacent somatic cells regulates GSC division. piwi encodes a highly basic novel protein, well conserved during evolution. We isolated piwi homologs in Caenorhabditis elegans and humans and also identified Arabidopsis piwi-like genes known to be required for meristem cell maintenance. Decreasing C. elegans piwi expression reduces the proliferation of GSC-equivalent cells. Thus, piwi represents a novel class of genes required for GSC division in diverse organisms.
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710 USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Cox
authors.forename: A
authors.initials: A
authors.lastname: Chao
authors.forename: J
authors.initials: J
authors.lastname: Baker
authors.forename: L
authors.initials: L
authors.lastname: Chang
authors.forename: D
authors.initials: D
authors.lastname: Qiao
authors.forename: H
authors.initials: H
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis; D060565:Argonaute Proteins; D017173:Caenorhabditis elegans / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D019143:Evolution, Molecular; D005260:Female; D017344:Genes, Insect; D005854:Germ Cells / Q000166:cytology*; D015801:Helminth Proteins / Q000235:genetics*; D006801:Humans; D018519:Meristem / Q000166:cytology; D008969:Molecular Sequence Data; D009154:Mutation; D009866:Oogenesis / Q000235:genetics; D011506:Proteins; D034743:RNA-Induced Silencing Complex; D017386:Sequence Homology, Amino Acid; D013234:Stem Cells / Q000166:cytology*
chemical_list: D060565:Argonaute Proteins; D029742:Caenorhabditis elegans Proteins; D029721:Drosophila Proteins; D015801:Helminth Proteins; C530363:PRG-1 protein, C elegans; C530626:PRG-2 protein, C elegans; D011506:Proteins; D034743:RNA-Induced Silencing Complex; C116498:piwi protein, Drosophila