Stella safeguards the oocyte methylome by preventing de novo methylation mediated by DNMT1

Nature. 2018 Dec;564(7734):136-140. doi: 10.1038/s41586-018-0751-5. Epub 2018 Nov 28.


Postnatal growth of mammalian oocytes is accompanied by a progressive gain of DNA methylation, which is predominantly mediated by DNMT3A, a de novo DNA methyltransferase1,2. Unlike the genome of sperm and most somatic cells, the oocyte genome is hypomethylated in transcriptionally inert regions2-4. However, how such a unique feature of the oocyte methylome is determined and its contribution to the developmental competence of the early embryo remains largely unknown. Here we demonstrate the importance of Stella, a factor essential for female fertility5-7, in shaping the oocyte methylome in mice. Oocytes that lack Stella acquire excessive DNA methylation at the genome-wide level, including in the promoters of inactive genes. Such aberrant hypermethylation is partially inherited by two-cell-stage embryos and impairs zygotic genome activation. Mechanistically, the loss of Stella leads to ectopic nuclear accumulation of the DNA methylation regulator UHRF18,9, which results in the mislocalization of maintenance DNA methyltransferase DNMT1 in the nucleus. Genetic analysis confirmed the primary role of UHRF1 and DNMT1 in generating the aberrant DNA methylome in Stella-deficient oocytes. Stella therefore safeguards the unique oocyte epigenome by preventing aberrant de novo DNA methylation mediated by DNMT1 and UHRF1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CCAAT-Enhancer-Binding Proteins
  • Cell Line
  • Cell Nucleus / metabolism
  • Chromosomal Proteins, Non-Histone
  • DNA (Cytosine-5-)-Methyltransferase 1 / antagonists & inhibitors
  • DNA (Cytosine-5-)-Methyltransferase 1 / metabolism*
  • DNA Methylation*
  • Embryonic Development
  • Epigenesis, Genetic*
  • Female
  • Genome / genetics
  • Humans
  • Mice
  • Nuclear Proteins / metabolism
  • Oocytes / metabolism*
  • Promoter Regions, Genetic / genetics
  • Repressor Proteins / deficiency
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Ubiquitin-Protein Ligases
  • Zygote / metabolism


  • CCAAT-Enhancer-Binding Proteins
  • Chromosomal Proteins, Non-Histone
  • Dppa3 protein, mouse
  • Nuclear Proteins
  • Repressor Proteins
  • DNA (Cytosine-5-)-Methyltransferase 1
  • Dnmt1 protein, mouse
  • Ubiquitin-Protein Ligases
  • Uhrf1 protein, mouse