Astrin regulates meiotic spindle organization, spindle pole tethering and cell cycle progression in mouse oocytes

Cell Cycle. 2009 Oct 15;8(20):3384-95. doi: 10.4161/cc.8.20.9885. Epub 2009 Oct 24.

Abstract

Astrin has been described as a microtubule and kinetochore protein required for the maintenance of sister chromatid cohesion and centrosome integrity in human mitosis. However, its role in mammalian oocyte meiosis is unclear. In this study, we find that Astrin is mainly associated with the meiotic spindle microtubules and concentrated on spindle poles at metaphase I and metaphase II stages. Taxol treatment and immunoprecipitation show that Astrin may interact with the centrosomal proteins Aurora-A or Plk1 to regulate microtubule organization and spindle pole integrity. Loss-of-function of Astrin by RNAi and overexpression of the coiled-coil domain results in spindle disorganization, chromosome misalignment and meiosis progression arrest. Thr24, Ser66 or Ser447 may be the potential phosphorylation sites of Astrin by Plk1, as site-directed mutation of these sites causes oocyte meiotic arrest at metaphase I with highly disordered spindles and disorganized chromosomes, although mutant Astrin localizes to the spindle apparatus. Taken together, these data strongly suggest that Astrin is critical for meiotic spindle assembly and maturation in mouse oocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aurora Kinase A
  • Aurora Kinases
  • Cell Cycle Proteins / analysis
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Meiosis
  • Metaphase
  • Mice
  • Microtubules / metabolism
  • Mutagenesis, Site-Directed
  • Nocodazole / pharmacology
  • Oocytes / cytology*
  • Oocytes / metabolism
  • Paclitaxel / pharmacology
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins / metabolism
  • RNA, Small Interfering / metabolism
  • Tubulin Modulators / pharmacology

Substances

  • Cell Cycle Proteins
  • Proto-Oncogene Proteins
  • RNA, Small Interfering
  • Spag5 protein, mouse
  • Tubulin Modulators
  • Aurka protein, mouse
  • Aurora Kinase A
  • Aurora Kinases
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1
  • Paclitaxel
  • Nocodazole