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Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination
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MEI4 – a central player in the regulation of meiotic DNA double-strand break formation in the mouse

Rajeev Kumar1, Norbert Ghyselinck2, Kei-ichiro Ishiguro3

  • 1Institute of Human Genetics, UPR 1142, CNRS. 141, Rue de la Cardonille, 34396 Montpellier, France.

Journal of Cell Science
|March 22, 2015
PubMed

Insights

Meiotic recombination initiates with programmed DNA double-strand breaks (DSBs), catalyzed by SPO11. Axis-associated MEI4 protein is crucial for DSB formation, with HORMAD1 and other factors regulating its localization and DSB levels.

Area of Science:

  • Genetics
  • Cell Biology
  • Molecular Biology

Background:

  • Meiotic recombination is initiated by programmed DNA double-strand breaks (DSBs) during meiotic prophase.
  • SPO11 catalyzes DSB formation, and repair occurs on meiotic chromosome axes.
  • The conserved MEI4 protein is essential for DSB formation and localizes to chromosome axes.

Purpose of the Study:

  • To investigate the role of HORMAD1 in MEI4 localization and its impact on meiotic DSB formation.
  • To identify other factors involved in regulating MEI4 localization on meiotic chromosome axes.
  • To understand the dynamics of MEI4 during meiotic prophase and its contribution to DSB regulation.

Main Methods:

  • Immunolocalization studies to assess MEI4 localization in the presence and absence of HORMAD1.
  • Quantitative analysis of axis-associated MEI4 levels and their correlation with DSB formation.
  • Analysis of MEI4 localization in mutants of MEI1, REC8, and RAD21L.

Main Results:

  • HORMAD1 is required for the localization of MEI4 to meiotic chromosome axes.
  • A quantitative correlation exists between axis-associated MEI4 levels and DSB formation, suggesting MEI4 acts as a limiting factor.
  • MEI1, REC8, and RAD21L are also important for proper MEI4 localization.

Conclusions:

  • Axis association of MEI4 is essential for meiotic DSB formation.
  • The dissociation of MEI4 from chromosome axes after DSB repair may contribute to the downregulation of DSB formation.
  • HORMAD1 plays a critical role in establishing the meiotic DSB machinery through MEI4 localization.
Keywords:
DNA double strand breakMeiosisRecombinationSynapsis

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