Binary specification of the embryonic lineage in Caenorhabditis elegans

Nature. 1997 Nov 20;390(6657):294-8. doi: 10.1038/36869.


In Caenorhabditis elegans, the early embryo contains five somatic founder cells (known as AB, MS, E, C and D) which give rise to very different lineages. Two simply produce twenty intestinal (E) or muscle (D) cells each, whereas the remainder produce a total of 518 cells which collectively contribute in a complex pattern to a variety of tissues. A central problem in embryonic development is to understand how the developmental potential of blastomeres is restricted to permit the terminal expression of such complex differentiation patterns. Here we identify a gene, lit-1, that appears to play a central role in controlling the asymmetry of cell division during embryogenesis in C. elegans. Mutants in lit-1 suggest that its product controls up to six consecutive binary switches which cause one of the two equivalent cells produced at each cleavage to assume a posterior fate. Most blastomere identities in C. elegans may therefore stem from a process of stepwise binary diversification.

MeSH terms

  • Animals
  • Blastomeres / cytology
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics
  • Cell Lineage / genetics*
  • Genes, Helminth*
  • Mutation