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

  • publication
  • 01-12-2001

van Loo, G., Schotte, P., van Gurp, M., Demol, H., Hoorelbeke, B., Gevaert, K., Rodriguez, I., Ruiz-Carrillo, A., Vandekerckhove, J., Declercq, W., Beyaert, R., Vandenabeele, P.. Cell Death Differ., Dec;8(12):1136-42

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.

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