The BCL-2 pathway preserves mammalian genome integrity by eliminating recombination-defective oocytes

Nat Commun. 2020 May 25;11(1):2598. doi: 10.1038/s41467-020-16441-z.

Abstract

DNA double-strand breaks (DSBs) are toxic to mammalian cells. However, during meiosis, more than 200 DSBs are generated deliberately, to ensure reciprocal recombination and orderly segregation of homologous chromosomes. If left unrepaired, meiotic DSBs can cause aneuploidy in gametes and compromise viability in offspring. Oocytes in which DSBs persist are therefore eliminated by the DNA-damage checkpoint. Here we show that the DNA-damage checkpoint eliminates oocytes via the pro-apoptotic BCL-2 pathway members Puma, Noxa and Bax. Deletion of these factors prevents oocyte elimination in recombination-repair mutants, even when the abundance of unresolved DSBs is high. Remarkably, surviving oocytes can extrude a polar body and be fertilised, despite chaotic chromosome segregation at the first meiotic division. Our findings raise the possibility that allelic variants of the BCL-2 pathway could influence the risk of embryonic aneuploidy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aneuploidy
  • Animals
  • Apoptosis
  • Apoptosis Regulatory Proteins / deficiency
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism
  • Cell Cycle Proteins / deficiency
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Chromosome Segregation
  • DNA Breaks, Double-Stranded
  • DNA-Binding Proteins / deficiency
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Endodeoxyribonucleases / deficiency
  • Endodeoxyribonucleases / genetics
  • Endodeoxyribonucleases / metabolism
  • Female
  • Fertilization
  • Genes, bcl-2
  • Meiosis / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mutation*
  • Oocytes / cytology
  • Oocytes / metabolism*
  • Phosphate-Binding Proteins / deficiency
  • Phosphate-Binding Proteins / genetics
  • Phosphate-Binding Proteins / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / deficiency
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Recombinational DNA Repair / genetics*
  • Signal Transduction
  • Tumor Suppressor Proteins / deficiency
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism
  • bcl-2-Associated X Protein / deficiency
  • bcl-2-Associated X Protein / genetics
  • bcl-2-Associated X Protein / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Bax protein, mouse
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Dmc1 protein, mouse
  • Msh5 protein, mouse
  • PUMA protein, mouse
  • Phosphate-Binding Proteins
  • Pmaip1 protein, mouse
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Proteins
  • bcl-2-Associated X Protein
  • Bcl2 protein, mouse
  • Endodeoxyribonucleases
  • meiotic recombination protein SPO11