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Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization
07:16

Isolation and Characterization of Mouse Antral Oocytes Based on Nucleolar Chromatin Organization

Published on: January 7, 2016

Fully grown mouse oocyte contains transcription inhibiting activity which acts through histone deacetylation

Ewa Borsuk1, Elwira Milik

  • 1Department of Embryology, Institute of Zoology, Warsaw University, Warsaw, Poland. borsuk@biol.uw.edu.pl

Molecular Reproduction and Development
|April 29, 2005
PubMed

Insights

Mouse oocytes stop RNA synthesis before maturation. Fusing active embryo cells with oocytes revealed that oocyte cytoplasm silences transcription via chromatin condensation and histone deacetylation.

Area of Science:

  • Developmental Biology
  • Molecular Biology
  • Cell Biology

Background:

  • Mouse oocytes are transcriptionally active during growth but cease RNA synthesis before maturation.
  • The mechanism for this transcriptional silencing in oocytes remains unclear.
  • Hypotheses suggest cytoplasmic factors from companion granulosa cells induce a nonpermissive state.

Purpose of the Study:

  • To investigate the mechanism of RNA synthesis termination in mouse oocytes.
  • To determine if oocyte cytoplasm can induce transcriptional silencing in active nuclei.
  • To analyze the role of chromatin modification in this process.

Main Methods:

  • Fusion of transcriptionally active blastomeres from 8-cell mouse embryos with non-transcribing, fully grown oocytes.
  • Culture of resulting hybrid cells for 27 hours.
  • Analysis of RNA synthesis and chromatin configuration in blastomere nuclei within the hybrid cells.

Main Results:

  • Transcription in blastomere nuclei was silenced within 27 hours of fusion with oocytes.
  • This silencing occurred without nuclear envelope breakdown, accompanied by chromatin condensation.
  • Core histone deacetylation was identified as a key factor in chromatin modification and transcriptional termination.

Conclusions:

  • Mouse oocyte cytoplasm possesses the ability to induce transcriptional silencing in active embryonic nuclei.
  • The process involves chromatin condensation and is mediated by core histone deacetylation.
  • These findings elucidate a novel mechanism for regulating gene expression during oocyte development.

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