Translational repression restricts expression of the C. elegans Nanos homolog NOS-2 to the embryonic germline

Dev Biol. 2006 Apr 1;292(1):244-52. doi: 10.1016/j.ydbio.2005.11.046. Epub 2006 Feb 24.


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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3' Untranslated Regions / physiology
  • Animals
  • Base Sequence
  • Blastomeres / metabolism
  • Caenorhabditis elegans / chemistry
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / antagonists & inhibitors
  • Caenorhabditis elegans Proteins / biosynthesis
  • Caenorhabditis elegans Proteins / chemistry
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / physiology
  • Carrier Proteins / physiology
  • Cell Lineage / physiology
  • Gene Expression Regulation, Developmental / physiology*
  • Germ Cells / metabolism
  • Molecular Sequence Data
  • Protein Biosynthesis / genetics*
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins
  • Structural Homology, Protein
  • Transgenes


  • 3' Untranslated Regions
  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • MEX-5 protein, C elegans
  • MEX-6 protein, C elegans
  • POS-1 protein, C elegans
  • RNA, Messenger
  • RNA-Binding Proteins
  • nos-2 protein, C elegans