Zygotic Expression of the Caudal Homolog pal-1 Is Required for Posterior Patterning in Caenorhabditis Elegans Embryogenesis

Dev Biol. 2001 Jan 1;229(1):71-88. doi: 10.1006/dbio.2000.9977.


Previous work has shown that the Caenorhabditis elegans gene pal-1, a homolog of Drosophila caudal, is required maternally for blastomere specification in the early embryo and postembryonically for tail development in males. We show here that embryonic (zygotic) transcription of pal-1 is also required for posterior patterning during later embryogenesis. Embryos homozygous for strong loss-of-function mutations arrest as nonviable L1 larvae with gross posterior defects. PAL-1 protein produced from zygotic transcripts is expressed dynamically during gastrulation and morphogenesis in specific cells of all major lineages except the germ line. Most expressing cells are undergoing cell movements or forming midline structures or both. Mutant embryos exhibit defects involving most of the expressing cells. Aberrant early cell positions are observed in posterior hypodermis, both in the C-lineage cells that express pal-1 and in the neighboring hypodermal seam cell precursors, which do not, as well as in posterior muscle derived from the C and D lineages. Defects in late gastrulation, ventral hypodermal enclosure, and formation of the rectum result from failures of cell movements of ABp and MS descendants. Limited mosaic analysis supports the view that most of the required pal-1 functions are cell autonomous.

Publication types

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

MeSH terms

  • Animals
  • Body Patterning*
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans Proteins*
  • Cell Lineage
  • Cell Movement
  • Drosophila Proteins
  • Epithelial Cells / cytology
  • Female
  • Gastrula / cytology
  • Helminth Proteins / genetics*
  • Homeodomain Proteins / genetics*
  • Mosaicism
  • Muscles / cytology
  • Mutagenesis
  • Mutagens
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Tissue Distribution
  • Trans-Activators*
  • Transcription Factors
  • Trioxsalen
  • Zygote


  • Caenorhabditis elegans Proteins
  • Drosophila Proteins
  • Helminth Proteins
  • Homeodomain Proteins
  • Mutagens
  • Trans-Activators
  • Transcription Factors
  • cad protein, Drosophila
  • pal-1 protein, C elegans
  • Trioxsalen