Condensins I and II are essential for construction of bivalent chromosomes in mouse oocytes

Mol Biol Cell. 2011 Sep;22(18):3465-77. doi: 10.1091/mbc.E11-05-0423. Epub 2011 Jul 27.

Abstract

In many eukaryotes, condensins I and II associate with chromosomes in an ordered fashion during mitosis and play nonoverlapping functions in their assembly and segregation. Here we report for the first time the spatiotemporal dynamics and functions of the two condensin complexes during meiotic divisions in mouse oocytes. At the germinal vesicle stage (prophase I), condensin I is present in the cytoplasm, whereas condensin II is localized within the nucleus. After germinal vesicle breakdown, condensin II starts to associate with chromosomes and becomes concentrated onto chromatid axes of bivalent chromosomes by metaphase I. REC8 "glues" chromosome arms along their lengths. In striking contrast to condensin II, condensin I localizes primarily around centromeric regions at metaphase I and starts to associate stably with chromosome arms only after anaphase I. Antibody injection experiments show that condensin functions are required for many aspects of meiotic chromosome dynamics, including chromosome individualization, resolution, and segregation. We propose that the two condensin complexes play distinctive roles in constructing bivalent chromosomes: condensin II might play a primary role in resolving sister chromatid axes, whereas condensin I might contribute to monopolar attachment of sister kinetochores, possibly by assembling a unique centromeric structure underneath.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism*
  • Animals
  • Antibodies / pharmacology
  • Antigens, Neoplasm / metabolism
  • Cell Cycle Proteins / metabolism
  • Chromosomal Proteins, Non-Histone / antagonists & inhibitors
  • Chromosomal Proteins, Non-Histone / metabolism
  • Chromosome Segregation / drug effects
  • Chromosomes, Mammalian / metabolism*
  • Cohesins
  • DNA Topoisomerases, Type II / metabolism
  • DNA-Binding Proteins / metabolism*
  • Female
  • Fluorescent Antibody Technique, Indirect
  • Kinetochores / drug effects
  • Kinetochores / metabolism
  • Meiosis*
  • Mice
  • Mice, Inbred ICR
  • Microscopy, Fluorescence
  • Multiprotein Complexes / metabolism*
  • Oocytes / metabolism*
  • Protein Transport

Substances

  • Antibodies
  • Antigens, Neoplasm
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Multiprotein Complexes
  • SMC2 protein, mouse
  • condensin complexes
  • Adenosine Triphosphatases
  • DNA Topoisomerases, Type II