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Updated: Dec 23, 2025

Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis
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Combining Mitotic Cell Synchronization and High Resolution Confocal Microscopy to Study the Role of Multifunctional Cell Cycle Proteins During Mitosis

Published on: December 5, 2017

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Mis12 controls cyclin B1 stabilization via Cdc14B-mediated APC/CCdh1 regulation during meiotic G2/M transition in

Guang-Yu Bai1,2, Min Ho Choe3, Jae-Sung Kim4

  • 1Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, 16419, Korea.

Development (Cambridge, England)
|April 29, 2020
PubMed

Insights

Mis12 protein is crucial for mammalian oocytes to transition from G2 phase to M phase, regulating cyclin B1 levels for germinal vesicle breakdown. However, it is not essential for later meiotic progression.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Molecular Biology

Background:

  • Mammalian oocytes arrest at G2/prophase I, resuming meiosis after hormonal stimulation.
  • Germinal vesicle breakdown (GVBD) marks the start of meiotic resumption, regulated by Cdk1/cyclin B1.
  • The role of Mis12 in oocyte meiotic progression remains unclear.

Purpose of the Study:

  • To investigate the function of Mis12 in mammalian oocyte meiosis.
  • To elucidate the mechanism by which Mis12 regulates meiotic entry.

Main Methods:

  • Mis12 depletion in oocytes using RNA interference.
  • Analysis of cyclin B1 levels, GVBD, spindle formation, and chromosome alignment.
  • Rescue experiments involving cyclin B1 overexpression or depletion of Cdc14B/Cdh1.
  • Immunofluorescence microscopy to determine Mis12 localization.

Main Results:

  • Mis12 depletion impaired GVBD by reducing cyclin B1 accumulation.
  • Overexpressing cyclin B1 or depleting Cdc14B/Cdh1 rescued GVBD in Mis12-depleted oocytes.
  • Rescued oocytes showed normal spindle and chromosome organization and extruded polar bodies.
  • Mis12-depleted oocytes formed pronuclei post-fertilization but arrested at the zygote stage.
  • Mis12 localized to the cytoplasm and spindle poles in oocytes, unlike somatic cells.

Conclusions:

  • Mis12 is essential for the G2/M transition in oocytes by regulating cyclin B1 levels via Cdc14B-APC/CCdh1.
  • Mis12 is dispensable for spindle and chromosome dynamics during meiotic maturation.
  • Mis12 plays a critical role in initiating meiosis but not in subsequent meiotic progression or early embryonic development.
Keywords:
APC/CCdh1G2/M transitionMeiotic resumptionMis12Oocyte maturation

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