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Two Distinct Pathways Leading to Nuclear Apoptosis

Two Distinct Pathways Leading to Nuclear Apoptosis Apaf-1 −/− or caspase-3 −/− cells treated with a variety of apoptosis inducers manifest apoptosis-associated alterations including the translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, large scale DNA fragmentation, and initial chromatin condensation (stage I). However, when compared with normal control cells, Apaf-1 −/− or caspase-3 −/− cells fail to exhibit oligonucleosomal chromatin digestion and a more advanced pattern of chromatin condensation (stage II). Microinjection of such cells with recombinant AIF only causes peripheral chromatin condensation (stage I), whereas microinjection with activated caspase-3 or its downstream target caspase-activated DNAse (CAD) causes a more pronounced type of chromatin condensation (stage II). Similarly, when added to purified HeLa nuclei, AIF causes stage I chromatin condensation and large-scale DNA fragmentation, whereas CAD induces stage II chromatin condensation and oligonucleosomal DNA degradation. Furthermore, in a cell-free system, concomitant neutralization of AIF and CAD is required to suppress the nuclear DNA loss caused by cytoplasmic extracts from apoptotic wild-type cells. In contrast, AIF depletion alone suffices to suppress the nuclear DNA loss contained in extracts from apoptotic Apaf-1 −/− or caspase-3 −/− cells. As a result, at least two redundant parallel pathways may lead to chromatin processing during apoptosis. One of these pathways involves Apaf-1 and caspases, as well as CAD, and leads to oligonucleosomal DNA fragmentation and advanced chromatin condensation. The other pathway, which is caspase-independent, involves AIF and leads to large-scale DNA fragmentation and peripheral chromatin condensation. apoptosis-inducing factor Apaf-1 chromatin condensation caspases caspase-activated DNase Footnotes S.A. Susin and E. Daugas contributed equally to this paper. Submitted: 13 January 2000 Revision requested 5 May 2000 Accepted: 13 June 2000 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Experimental Medicine Rockefeller University Press

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References (31)

Publisher
Rockefeller University Press
Copyright
© 2000 The Rockefeller University Press
ISSN
0022-1007
eISSN
1540-9538
DOI
10.1084/jem.192.4.571
Publisher site
See Article on Publisher Site

Abstract

Apaf-1 −/− or caspase-3 −/− cells treated with a variety of apoptosis inducers manifest apoptosis-associated alterations including the translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, large scale DNA fragmentation, and initial chromatin condensation (stage I). However, when compared with normal control cells, Apaf-1 −/− or caspase-3 −/− cells fail to exhibit oligonucleosomal chromatin digestion and a more advanced pattern of chromatin condensation (stage II). Microinjection of such cells with recombinant AIF only causes peripheral chromatin condensation (stage I), whereas microinjection with activated caspase-3 or its downstream target caspase-activated DNAse (CAD) causes a more pronounced type of chromatin condensation (stage II). Similarly, when added to purified HeLa nuclei, AIF causes stage I chromatin condensation and large-scale DNA fragmentation, whereas CAD induces stage II chromatin condensation and oligonucleosomal DNA degradation. Furthermore, in a cell-free system, concomitant neutralization of AIF and CAD is required to suppress the nuclear DNA loss caused by cytoplasmic extracts from apoptotic wild-type cells. In contrast, AIF depletion alone suffices to suppress the nuclear DNA loss contained in extracts from apoptotic Apaf-1 −/− or caspase-3 −/− cells. As a result, at least two redundant parallel pathways may lead to chromatin processing during apoptosis. One of these pathways involves Apaf-1 and caspases, as well as CAD, and leads to oligonucleosomal DNA fragmentation and advanced chromatin condensation. The other pathway, which is caspase-independent, involves AIF and leads to large-scale DNA fragmentation and peripheral chromatin condensation. apoptosis-inducing factor Apaf-1 chromatin condensation caspases caspase-activated DNase Footnotes S.A. Susin and E. Daugas contributed equally to this paper. Submitted: 13 January 2000 Revision requested 5 May 2000 Accepted: 13 June 2000

Journal

The Journal of Experimental MedicineRockefeller University Press

Published: Aug 21, 2000

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