Evolution of germ-line signals that regulate growth and aging in nematodes

Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):769-74. doi: 10.1073/pnas.012511099.


We show that a signal from the germ line represses growth in the nematode Caenorhabditis elegans. Laser-microbeam ablation of cells that give rise to the germ line causes adults to become giant. Ablation of these cells in self-sterile mutant worms also causes gigantism, suggesting that the germ line represses growth because it is the source of a growth-antagonizing signal rather than because of a sink of resources required for reproduction. The C. elegans germ line also emits a signal that represses longevity. This longevity-repressing signal requires the activity of DAF-16, a forkhead/winged-helix transcription factor, but we find that that the growth-repressing signal does not. The growth-repressing signal also does not require the activity of DBL-1, a transforming growth factor beta-related protein that promotes growth in worms. By ablating the germ-line precursors of other species of free-living nematodes, we also found that both the growth-repressing and longevity-repressing signals are evolutionarily variable. Some species have both signals; others have just one or the other. We suggest that variation in germ-line signaling contributes to body size and life-history diversity in the nematodes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / genetics
  • Animals
  • Antibody Diversity
  • Biological Evolution*
  • Body Constitution / genetics
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans Proteins / genetics
  • Female
  • Forkhead Transcription Factors
  • Genes, Helminth
  • Longevity / genetics
  • Male
  • Mutation
  • Signal Transduction
  • Transcription Factors / genetics


  • Caenorhabditis elegans Proteins
  • Forkhead Transcription Factors
  • Transcription Factors
  • daf-16 protein, C elegans