Involvement of caspase 3-activated DNase in internucleosomal DNA cleavage induced by diverse apoptotic stimuli

Oncogene. 1999 Aug 5;18(31):4401-8. doi: 10.1038/sj.onc.1202868.


Degradation of chromosomal DNA into nucleosome-sized fragments is one of the characteristics of apoptotic cell death. Here, we examined whether caspase-activated DNase (CAD) is responsible for the DNA fragmentation that occurs upon exposure to various apoptotic stimuli. When human Jurkat cells were exposed to etoposide, or UV or gamma radiation, a caspase-3-like protease was activated, and nuclear DNA was fragmented. Human TF-1 cells, which are dependent on granulocyte-macrophage colony-stimulating factor (GM-CSF), also underwent apoptosis accompanied by the activation of caspase-3-like protease and DNA fragmentation, when cultured without the cytokine. Both Jurkat and TF-1 cells expressed two forms of ICAD, ICAD-L and ICAD-S, which were cleaved upon exposure to these apoptotic stimuli. Among eight different caspases examined, recombinant caspases 3 and 7 specifically cleaved ICAD synthesized in a cell-free system. An expression plasmid containing mouse ICAD-L mutated at the caspase-3-recognition sites was then introduced into Jurkat and TF-1 cells. When the transformants were induced to undergo apoptosis (by treatment with etoposide, UV or gamma radiation for Jurkat cells, or factor withdrawal for TF-1 cells) they did not show DNA fragmentation, although they still died as a result of these stimuli. These results indicated that CAD, released from ICAD by caspase activation, is involved in the nuclear DNA fragmentation induced by these apoptotic stimuli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis* / drug effects
  • Apoptosis* / radiation effects
  • Caspase 3
  • Caspases / metabolism*
  • Cell Line
  • DNA / metabolism*
  • DNA Fragmentation
  • Deoxyribonucleases / genetics
  • Deoxyribonucleases / metabolism*
  • Enzyme Activation / drug effects
  • Enzyme Activation / radiation effects
  • Etoposide / toxicity
  • Gamma Rays*
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Jurkat Cells
  • Kinetics
  • Mice
  • Nucleosomes / drug effects
  • Nucleosomes / metabolism*
  • Plasmids
  • Recombinant Proteins / metabolism
  • Transfection
  • Ultraviolet Rays*


  • Isoenzymes
  • Nucleosomes
  • Recombinant Proteins
  • Etoposide
  • DNA
  • Deoxyribonucleases
  • caspase-activated deoxyribonuclease
  • CASP3 protein, human
  • Casp3 protein, mouse
  • Caspase 3
  • Caspases