title: Cell-cycle quiescence maintains Caenorhabditis elegans germline stem cells independent of GLP-1/Notch.
abstract: Many types of adult stem cells exist in a state of cell-cycle quiescence, yet it has remained unclear whether quiescence plays a role in maintaining the stem cell fate. Here we establish the adult germline of Caenorhabditis elegans as a model for facultative stem cell quiescence. We find that mitotically dividing germ cells--including germline stem cells--become quiescent in the absence of food. This quiescence is characterized by a slowing of S phase, a block to M-phase entry, and the ability to re-enter M phase rapidly in response to re-feeding. Further, we demonstrate that cell-cycle quiescence alters the genetic requirements for stem cell maintenance: The signaling pathway required for stem cell maintenance under fed conditions--GLP-1/Notch signaling--becomes dispensable under conditions of quiescence. Thus, cell-cycle quiescence can itself maintain stem cells, independent of the signaling pathway otherwise essential for such maintenance.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.|The Ellison Medical Foundation Fellow of the Life Sciences Research Foundation, The Lawrence Ellison Foundation, Mount Airy, United States.
authors.forename: Hannah S
authors.initials: HS
authors.lastname: Seidel
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.|Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, United States.
authors.forename: Judith
authors.initials: J
authors.lastname: Kimble
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002453:Cell Cycle; D005247:Feeding Behavior; D005854:Germ Cells / Q000502:physiology*; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction; D013234:Stem Cells / Q000502:physiology*
chemical_list: D029742:Caenorhabditis elegans Proteins; C060620:Glp-1 protein, C elegans; D051880:Receptors, Notch
keywords: C. elegans; GLP-1/Notch; cell biology; cell cycle; developmental biology; germline stem cells; quiescence; stem cells