Endonuclease G: a mitochondrial protein released in apoptosis and involved in caspase-independent DNA degradation

Cell Death Differ. 2001 Dec;8(12):1136-42. doi: 10.1038/sj.cdd.4400944.


A hallmark of apoptosis is the fragmentation of nuclear DNA. Although this activity involves the caspase-3-dependent DNAse CAD (caspase-activated DNAse), evidence exists that DNA fragmentation can occur independently of caspase activity. Here we report on the ability of truncated Bid (tBid) to induce the release of a DNAse activity from mitochondria. This DNAse activity was identified by mass spectrometry as endonuclease G, an abundant 30 kDa protein released from mitochondria under apoptotic conditions. No tBid-induced endonuclease G release could be observed in mitochondria from Bcl-2-transgenic mice. The in vivo occurrence of endonuclease G release from mitochondria during apoptosis was confirmed in the liver from mice injected with agonistic anti-Fas antibody and is completely prevented in Bcl-2 transgenic mice. These data indicate that endonuclease G may be involved in CAD-independent DNA fragmentation during cell death pathways in which truncated Bid is generated.

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • BH3 Interacting Domain Death Agonist Protein
  • Carrier Proteins / pharmacology
  • Caspases / metabolism*
  • Cytochrome c Group / metabolism
  • DNA Fragmentation*
  • Endodeoxyribonucleases / metabolism
  • Endodeoxyribonucleases / physiology*
  • Genes, bcl-2 / physiology
  • Mice
  • Mitochondrial Proteins / metabolism
  • Mitochondrial Proteins / physiology*


  • BH3 Interacting Domain Death Agonist Protein
  • Bid protein, mouse
  • Carrier Proteins
  • Cytochrome c Group
  • Mitochondrial Proteins
  • Endodeoxyribonucleases
  • endonuclease G
  • Caspases