title: A planarian p53 homolog regulates proliferation and self-renewal in adult stem cell lineages.
abstract: The functions of adult stem cells and tumor suppressor genes are known to intersect. However, when and how tumor suppressors function in the lineages produced by adult stem cells is unknown. With a large population of stem cells that can be manipulated and studied in vivo, the freshwater planarian is an ideal system with which to investigate these questions. Here, we focus on the tumor suppressor p53, homologs of which have no known role in stem cell biology in any invertebrate examined thus far. Planaria have a single p53 family member, Smed-p53, which is predominantly expressed in newly made stem cell progeny. When Smed-p53 is targeted by RNAi, the stem cell population increases at the expense of progeny, resulting in hyper-proliferation. However, ultimately the stem cell population fails to self-renew. Our results suggest that prior to the vertebrates, an ancestral p53-like molecule already had functions in stem cell proliferation control and self-renewal.
authors.affiliation: Department of Neurobiology and Anatomy, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84132, USA.
authors.forename: Bret J
authors.initials: BJ
authors.lastname: Pearson
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sánchez Alvarado
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology* / Q000378:metabolism*; D000818:Animals; D019070:Cell Lineage / Q000502:physiology*; D005434:Flow Cytometry; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D010932:Planarians / Q000166:cytology* / Q000378:metabolism*; D034622:RNA Interference; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D015801:Helminth Proteins; D016159:Tumor Suppressor Protein p53