nanos1 is required to maintain oocyte production in adult zebrafish

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.03.007 Byline: Bruce W. Draper (a)(c), Claire M. McCallum (b), Cecilia B. Moens (a) Keywords: Development; Zebrafish; Nanos; Vasa; Ziwi; Germline stem cells; Primordial germ cells; Ovary; Oogenesis; TILLING Abstract: Development of the germline requires the specification and survival of primordial germ cells (PGCs) in the embryo as well as the maintenance of gamete production during the reproductive life of the adult. These processes appear to be fundamental to all Metazoans, and some components of the genetic pathway regulating germ cell development and function are evolutionarily conserved. In both vertebrates and invertebrates, nanos-related genes, which encode RNA-binding zinc finger proteins, have been shown to play essential and conserved roles during germ cell formation. In Drosophila, maternally supplied nanos is required for survival of PGCs in the embryo, while in adults, nanos is required for the continued production of oocytes by maintaining germline stem cells self-renewal. In mice and zebrafish, nanos orthologs are required for PGC survival during embryogenesis, but a role in adults has not been explored. We show here that nanos1 in zebrafish is expressed in early stage oocytes in the adult female germline. We have identified a mutation in nanos1 using a reverse genetics method and show that young female nanos mutants contain oocytes, but fail to maintain oocyte production. This progressive loss of fertility in homozygous females is not a phenotype that has been described previously in the zebrafish and underlines the value of a reverse genetics approach in this model system. Author Affiliation: (a) Howard Hughes Medical Institute and Fred Hutchinson Cancer Research Center, P.O. Box 19024, Seattle, WA 98109, USA (b) Arcadia Biosciences, 1102 Columbia St., Suite 600, Seattle, WA 98104, USA (c) Section of Molecular and Cellular Biology, University of California, Davis One Shields Ave., Davis, CA 95616, USA Article History: Received 29 April 2006; Revised 6 March 2007; Accepted 6 March 2007