title: Translational repression restricts expression of the C. elegans Nanos homolog NOS-2 to the embryonic germline.
abstract: Members of the nanos gene family are evolutionarily conserved regulators of germ cell development. In several organisms, Nanos protein expression is restricted to the primordial germ cells (PGCs) during early embryogenesis. Here, we investigate the regulation of the Caenorhabditis elegans nanos homolog nos-2. We find that the nos-2 RNA is translationally repressed. In the adult germline, translation of the nos-2 RNA is inhibited in growing oocytes, and this inhibition depends on a short stem loop in the nos-2 3'UTR. In embryos, nos-2 translation is repressed in early blastomeres, and this inhibition depends on a second region in the nos-2 3'UTR. nos-2 RNA is also degraded in somatic blastomeres by a process that is independent of translational repression and requires the CCCH finger proteins MEX-5 and MEX-6. Finally, the germ plasm component POS-1 activates nos-2 translation in the PGCs. A combination of translational repression, RNA degradation, and activation by germ plasm has also been implicated in the regulation of nanos homologs in Drosophila and zebrafish, suggesting the existence of conserved mechanisms to restrict Nanos expression to the germline.
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University, School of Medicine, Baltimore, MD 21205-2185, USA.
authors.forename: Ingrid
authors.initials: I
authors.lastname: D'Agostino
authors.forename: Chris
authors.initials: C
authors.lastname: Merritt
authors.forename: Pei-Lung
authors.initials: PL
authors.lastname: Chen
authors.forename: Geraldine
authors.initials: G
authors.lastname: Seydoux
authors.forename: Kuppuswamy
authors.initials: K
authors.lastname: Subramaniam
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D001757:Blastomeres / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D019070:Cell Lineage / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005854:Germ Cells / Q000378:metabolism; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D040681:Structural Homology, Protein; D019076:Transgenes
chemical_list: D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; C410587:MEX-5 protein, C elegans; C410589:MEX-6 protein, C elegans; C117258:POS-1 protein, C elegans; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C400703:nos-2 protein, C elegans