The Caenorhabditis elegans par-5 gene encodes a 14-3-3 protein required for cellular asymmetry in the early embryo

Dev Biol. 2002 Jan 1;241(1):47-58. doi: 10.1006/dbio.2001.0489.


The establishment of anterior-posterior polarity in the Caenorhabditis elegans embryo requires the activity of the maternally expressed par genes. We report the identification and analysis of a new par gene, par-5. We show that par-5 is required for asynchrony and asymmetry in the first embryonic cell divisions, normal pseudocleavage, normal cleavage spindle orientation at the two-cell stage, and localization of P granules and MEX-5 during the first and subsequent cell cycles. Furthermore, par-5 activity is required in the first cell cycle for the asymmetric cortical localization of PAR-1 and PAR-2 to the posterior, and PAR-3, PAR-6, and PKC-3 to the anterior. When PAR-5 is reduced by mutation or by RNA interference, these proteins spread around the cortex of the one-cell embryo and partially overlap. We have shown by sequence analysis of par-5 mutants and by RNA interference that the par-5 gene is the same as the ftt-1 gene, and encodes a 14-3-3 protein. The PAR-5 14-3-3 protein is present in gonads, oocytes, and early embryos, but is not asymmetrically distributed. Our analysis indicates that the par-5 14-3-3 gene plays a crucial role in the early events leading to polarization of the C. elegans zygote.

Publication types

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

MeSH terms

  • 14-3-3 Proteins
  • Amino Acid Sequence
  • Animals
  • Body Patterning / genetics
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • Cell Division
  • DNA, Helminth / genetics
  • Female
  • Fertility / genetics
  • Genes, Helminth*
  • Helminth Proteins / genetics
  • Male
  • Molecular Sequence Data
  • Mutation
  • Phenotype
  • RNA, Helminth / genetics
  • Tyrosine 3-Monooxygenase / genetics*
  • Tyrosine 3-Monooxygenase / metabolism
  • Zygote / cytology


  • 14-3-3 Proteins
  • Caenorhabditis elegans Proteins
  • DNA, Helminth
  • Helminth Proteins
  • RNA, Helminth
  • par-5 protein, C elegans
  • Tyrosine 3-Monooxygenase