Regulatory Elements Required for Development of Caenorhabditis Elegans Hermaphrodites Are Conserved in the tra-2 Homologue of C. Remanei, a male/female Sister Species

Genetics. 2000 May;155(1):105-16.


The Caenorhabditis elegans hermaphrodite is essentially a female that produces sperm. In C. elegans, tra-2 promotes female fates and must be repressed to achieve hermaphrodite spermatogenesis. In an effort to learn how mating systems evolve, we have cloned tra-2 from C. remanei, the closest gonochoristic relative of C. elegans. We found its structure to be similar to that of Ce-tra-2 but its sequence to be divergent. RNA interference demonstrates that Cr-tra-2 promotes female fates. Two sites of tra-2 regulation are required for the onset of hermaphrodite spermatogenesis in C. elegans. One, the MX region of TRA-2, is as well conserved in C. remanei as it is in C. briggsae (another male/hermaphrodite species), suggesting that this control is not unique to hermaphrodites. Another, the DRE/TGE element of the tra-2 3' UTR, was not detected by sequence analysis. However, gel-shift assays demonstrate that a factor in C. remanei can bind specifically to the Cr-tra-2 3' UTR, suggesting that this translational control is also conserved. We propose that both controls are general and do not constitute a novel "switch" that enables sexual mosaicism in hermaphrodites. However, subtle quantitative or qualitative differences in their employment may underlie differences in mating system seen in Caenorhabditis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / physiology
  • Caenorhabditis elegans Proteins*
  • Cloning, Molecular
  • Conserved Sequence*
  • Female
  • Genes, Helminth*
  • Helminth Proteins / genetics*
  • Helminth Proteins / physiology
  • Male
  • Membrane Proteins / genetics*
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • RNA, Helminth
  • RNA, Messenger
  • Regulatory Sequences, Nucleic Acid*
  • Sequence Homology, Amino Acid
  • Sex Determination Processes


  • 3' Untranslated Regions
  • Caenorhabditis elegans Proteins
  • Helminth Proteins
  • Membrane Proteins
  • RNA, Helminth
  • RNA, Messenger
  • tra-2 protein, C elegans