Extragenic suppressors of a dominant masculinizing her-1 mutation in C. elegans identify two new genes that affect sex determination in different ways

Genesis. 2002 Nov;34(3):184-95. doi: 10.1002/gene.10118.


The her-1 regulatory switch gene in C. elegans sex determination is normally active in XO animals, resulting in male development, and inactive in XX animals, allowing hermaphrodite development. The her-1(n695gf) mutation results in the incomplete transformation of XX animals into phenotypic males. We describe four extragenic mutations that suppress the masculinized phenotype of her-1(n695gf) XX. They define two previously undescribed genes, sup-26 and sup-27. All four mutations exhibit semidominance of suppression and by themselves have no visible effects on sex determination in otherwise genotypically wild-type XX or XO animals. Analysis of interactions with mutations in the major sex-determining genes show that sup-26 and sup-27 influence sex determination in fundamentally different ways. sup-26 appears to act independently of her-1 to negatively modulate synthesis or function of tra-2 in both XX and XO animals. sup-27 may play a role in X-chromosome dosage compensation and influence sex determination indirectly.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • DNA-Binding Proteins*
  • Dosage Compensation, Genetic
  • Genes, Suppressor* / physiology
  • Helminth Proteins / genetics*
  • Helminth Proteins / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mutation
  • Sex Determination Processes
  • Transcription Factors*
  • X Chromosome


  • Caenorhabditis elegans Proteins
  • DNA-Binding Proteins
  • Helminth Proteins
  • Membrane Proteins
  • Sdc-3 protein, C elegans
  • Transcription Factors
  • her-1 protein, C elegans
  • tra-1 protein, C elegans
  • tra-2 protein, C elegans