Asymmetrically distributed PAR-3 protein contributes to cell polarity and spindle alignment in early C. elegans embryos

Cell. 1995 Dec 1;83(5):743-52. doi: 10.1016/0092-8674(95)90187-6.


The par-3 gene is required for establishing polarity in early C. elegans embryos. Embryos from par-3 homozygous mothers show defects in segregation of cytoplasmic determinants and in positioning of the early cleavage spindles. We report here that the PAR-3 protein is asymmetrically distributed at the periphery of the zygote and asymmetrically dividing blastomeres of the germline lineage. The PAR-3 distribution is roughly the reciprocal of PAR-1, another protein required for establishing embryonic polarity in C. elegans. Analysis of the distribution of PAR-3 and PAR-1 in other par mutants reveals that par-2 activity is required for proper localization of PAR-3 and that PAR-3 is required for proper localization of PAR-1. In addition, the distribution of the PAR-3 protein correlates with differences in cleavage spindle orientation and suggests a mechanism by which PAR-3 contributes to control of cleavage pattern.

Publication types

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

MeSH terms

  • Animals
  • Blastomeres / chemistry
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins*
  • Cell Cycle
  • Cell Polarity / physiology*
  • Cloning, Molecular
  • Embryo, Nonmammalian / chemistry
  • Gene Expression Regulation, Developmental
  • Genes, Helminth / genetics
  • Helminth Proteins / analysis*
  • Helminth Proteins / genetics
  • Helminth Proteins / physiology
  • Molecular Sequence Data
  • Protein-Serine-Threonine Kinases
  • RNA / analysis
  • RNA, Helminth / analysis
  • Sequence Analysis, DNA
  • Zygote / chemistry


  • Caenorhabditis elegans Proteins
  • Helminth Proteins
  • RNA, Helminth
  • par-2 protein, C elegans
  • RNA
  • PAR-3 protein, C elegans
  • Protein-Serine-Threonine Kinases

Associated data

  • GENBANK/U25032