Symmetry breaking and polarity establishment during mouse oocyte maturation

Kexi Yi, Boris Rubinstein, Rong Li

Research output: Contribution to journalReview articlepeer-review


Mammalian oocyte meiosis encompasses two rounds of asymmetric divisions to generate a totipotent haploid egg and, as by-products, two small polar bodies. Two intracellular events, asymmetric spindle positioning and cortical polarization, are critical to such asymmetric divisions. Actin but not microtubule cytoskeleton has been known to be directly involved in both events. Recent work has revealed a positive feedback loop between chromosome-mediated cortical activation and the Arp2/3-orchestrated cytoplasmic streaming that moves chromosomes. This feedback loop not only maintains meiotic II spindle position during metaphase II arrest, but also brings about symmetry breaking during meiosis I. Prior to an Arp2/3- dependent phase of fast movement, meiotic I spindle experiences a slow and non-directional first phase of migration driven by a pushing force from Fmn2-mediated actin polymerization. In addition to illustrating these molecular mechanisms, mathematical simulations are presented to elucidate mechanical properties of actin-dependent force generation in this system.

Original languageEnglish (US)
Article number20130002
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Issue number1629
StatePublished - Nov 2013
Externally publishedYes


  • Actin dynamics
  • Polarity establishment
  • Spindle migration
  • Symmetry breaking

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)


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