PAR-3 defines a central subdomain of the cortical actin cap in mouse eggs

Dev Biol. 2005 Apr 1;280(1):38-47. doi: 10.1016/j.ydbio.2004.12.034.

Abstract

The evolutionarily conserved partitioning defective (PAR) protein PAR-3 is pivotal for establishing and maintaining cell polarity. During mammalian oocyte maturation, the radially symmetric oocyte is transformed into a highly polarized metaphase II (MII)-arrested egg. We therefore examined several aspects of PAR-3 expression during oocyte maturation. We cloned two novel PAR-3 transcripts from an oocyte library that likely encode proteins of Mr = 73 K and 133 K that are phosphorylated during maturation. PAR-3, which is found throughout the GV-intact oocyte, becomes asymmetrically localized during meiosis. Following germinal vesicle breakdown, PAR-3 surrounds the condensing chromosomes and associates with the meiotic spindles. Prior to emission of the first and second polar bodies, PAR-3 is located within a central subdomain of the polarized actin cap, which overlies the spindle. This cortical PAR-3 localization depends on intact microfilaments. These results suggest a role for PAR-3 in establishing asymmetry in the egg and in defining the future site of polar body emission.

Publication types

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

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Actins / metabolism*
  • Adaptor Proteins, Signal Transducing
  • Animals
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Cell Cycle Proteins
  • Cell Polarity*
  • Cytoskeleton / metabolism
  • Female
  • Isoenzymes / metabolism
  • Meiosis / physiology
  • Mice
  • Microtubules / metabolism
  • Oocytes / cytology*
  • Oocytes / physiology*
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Kinase C / metabolism
  • Protein Structure, Tertiary

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • Cell Adhesion Molecules
  • Cell Cycle Proteins
  • Isoenzymes
  • Pard3 protein, mouse
  • Protein Isoforms
  • Protein Kinase C