The Caenorhabditis elegans eukaryotic initiation factor 5A homologue, IFF-1, is required for germ cell proliferation, gametogenesis and localization of the P-granule component PGL-1

Mech Dev. 2004 Mar;121(3):213-24. doi: 10.1016/j.mod.2004.02.001.


Eukaryotic initiation factor 5A (eIF-5A) was originally isolated as a translation initiation factor. However, this function has since been reconsidered, with recent studies pointing to roles for eIF-5A in mRNA metabolism and trafficking [Microbiol. Mol. Biol. Rev. 66 (2002) 460; Eur. Mol. Biol. Org. J. 17 (1998) 2914]. The Caenorhabditis elegans genome contains two eIF-5A homologues, iff-1 and iff-2, whose functions in vivo were examined in this study. The iff-2 mutation causes somatic defects that include slow larval growth and disorganized somatic gonadal structures in hermaphrodites. iff-2 males show disorganized tail sensory rays and spicules. On the other hand, iff-1 mRNA is expressed in the gonad, and the lack of iff-1 activity causes sterility with an underproliferated germline resulting from impaired mitotic proliferation in both hermaphrodites and males. In spite of underproliferation, meiotic nuclei are observed, as revealed by presence of immunoreactivity to the anti-HIM-3 antibody; however, no gametogenesis occurs in the iff-1 gonads. These phenotypes are in part similar to the mutants affected in the components of P granules, which are the C. elegans counterparts of germ granules [Curr. Top Dev. Biol. 50 (2000) 155]. We found that localization of the P-granule component PGL-1 to P granules is disrupted in the iff-1 mutant. In summary, the two C. elegans homologues of eIF-5A act in different tissues: IFF-2 is required in the soma, and IFF-1 is required in the germline for germ cell proliferation, for gametogenesis after entry into meiosis, and for proper PGL-1 localization on P granules.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / analysis*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Caenorhabditis elegans Proteins / physiology*
  • DNA / metabolism
  • Gametogenesis*
  • Gene Expression
  • Germ Cells / cytology
  • Germ Cells / growth & development*
  • Germ-Line Mutation
  • Immunochemistry
  • Meiosis
  • Molecular Sequence Data
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism
  • Peptide Initiation Factors / physiology*
  • RNA Interference
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / analysis*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • RNA-Binding Proteins / physiology*
  • Sequence Alignment


  • Caenorhabditis elegans Proteins
  • IFF-1 protein, C elegans
  • IFF-2 protein, C elegans
  • PGL-1 protein, C elegans
  • Peptide Initiation Factors
  • RNA, Messenger
  • RNA-Binding Proteins
  • eukaryotic translation initiation factor 5A
  • DNA