GLD-3, a bicaudal-C homolog that inhibits FBF to control germline sex determination in C. elegans

Dev Cell. 2002 Nov;3(5):697-710. doi: 10.1016/s1534-5807(02)00322-2.


The FBF RNA binding proteins control multiple aspects of C. elegans germline development, including sex determination. FBF promotes the oocyte fate at the expense of spermatogenesis by binding a regulatory element in the fem-3 3'UTR and repressing this sex-determining gene. Here we report the discovery of GLD-3, a Bicaudal-C homolog and cytoplasmic protein that physically interacts with FBF. Using RNAi and a gld-3 deletion mutant, we show that GLD-3 promotes the sperm fate, a sex determination effect opposite to that of FBF. By epistasis analysis, GLD-3 acts upstream of FBF, and, in a yeast three-hybrid assay, GLD-3 interferes specifically with FBF binding to the fem-3 3'UTR. We propose that GLD-3 binds FBF and thereby inhibits its repression of target mRNAs.

Publication types

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

MeSH terms

  • 3' Untranslated Regions
  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cytoplasm / metabolism
  • Drosophila Proteins
  • Female
  • Male
  • Molecular Sequence Data
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Sex Determination Processes*
  • Spermatogenesis / physiology
  • Spermatozoa / physiology*


  • 3' Untranslated Regions
  • BicC protein, Drosophila
  • Caenorhabditis elegans Proteins
  • Drosophila Proteins
  • GLD-3 protein, C elegans
  • RNA-Binding Proteins
  • fem-3 protein, C elegans
  • fem-3-binding protein, C elegans