MEX-3 is a KH domain protein that regulates blastomere identity in early C. elegans embryos

Cell. 1996 Oct 18;87(2):205-16. doi: 10.1016/s0092-8674(00)81339-2.


After the first division of the C. elegans embryo, the posterior blastomere can produce numerous muscles while the anterior blastomere cannot. We show here that maternal-effect lethal mutations in the gene mex-3 cause descendants of the anterior blastomere to produce muscles by a pattern of development similar to that of a descendant of the wild-type posterior blastomere. mex-3 encodes a probable RNA-binding protein that is distributed unequally in early embryos and that is a component of germline-specific granules called P granules. We propose that MEX-3 contributes to anterior-posterior asymmetry by regulating one or more mRNAs involved in specifying the fate of the posterior blastomere.

Publication types

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

MeSH terms

  • Alleles
  • Animals
  • Base Sequence
  • Blastomeres / cytology*
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans Proteins*
  • Cytoplasm / metabolism
  • Cytoplasmic Granules / metabolism
  • Gene Expression Regulation, Developmental
  • Genes, Helminth
  • Genes, Lethal
  • Helminth Proteins / physiology*
  • Humans
  • In Situ Hybridization
  • Molecular Sequence Data
  • Morphogenesis
  • Muscles / embryology
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / genetics*
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • Caenorhabditis elegans Proteins
  • Helminth Proteins
  • MEX-3 protein, C elegans
  • RNA, Messenger
  • RNA-Binding Proteins

Associated data

  • GENBANK/U67864