PAR-1 and the microtubule-associated proteins CLASP2 and dynactin-p50 have specific localisation on mouse meiotic and first mitotic spindles

Reproduction. 2005 Sep;130(3):311-20. doi: 10.1530/rep.1.00651.


The site of second meiotic division, marked by the second polar body, is an important reference point in the early mouse embryo. To study its formation, we look at the highly asymmetric meiotic divisions. For extrusion of the small polar bodies during meiosis, the spindles must be located cortically. The positioning of meiotic spindles is known to involve the actin cytoskeleton, but whether microtubules are also involved is not clear. In this study we investigated the patterns of localisation of microtubule regulatory proteins in mouse oocytes. PAR-1 is a member of the PAR (partitioning-defective) family with known roles in regulation of microtubule stability and spindle positioning in other model systems. Here we show its specific localisation on mouse meiotic and first mitotic spindles. In addition, the microtubule-associated proteins CLASP2 (a CLIP associating protein) and dynactin-p50 are found on kinetochores and a subset of microtubule-organising centres. Thus we show specific localisation of microtubule regulatory proteins in mouse oocytes, which could indicate roles in meiotic spindle organisation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western / methods
  • Cleavage Stage, Ovum / chemistry
  • Cleavage Stage, Ovum / ultrastructure*
  • Dynactin Complex
  • Female
  • Immunohistochemistry / methods
  • Male
  • Meiosis
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Microtubule-Associated Proteins / analysis*
  • Microtubule-Associated Proteins / genetics
  • Microtubules / ultrastructure
  • Oogenesis
  • Ovum / chemistry*
  • Ovum / physiology
  • RNA, Messenger / analysis
  • Receptor, PAR-1 / analysis*
  • Receptor, PAR-1 / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Spindle Apparatus / chemistry*
  • Tubulin / analysis


  • CLASP2 protein, mouse
  • Dynactin Complex
  • Microtubule-Associated Proteins
  • RNA, Messenger
  • Receptor, PAR-1
  • Tubulin