The 40-kDa subunit of DNA fragmentation factor induces DNA fragmentation and chromatin condensation during apoptosis.
We report here the reconstitution of a pathway that leads to the apoptotic changes in nuclei by using recombinant DNA fragmentation factor (DFF), a heterodimeric protein of 40 and 45 kDa. Coexpression of DFF40 and DFF45 is required to generate recombinant DFF, which becomes activated when DFF45 is cleaved by caspase-3. The cleaved fragments of DFF45 dissociate from the DFF40, the active component of DFF. Purified DFF40 exhibited an intrinsic DNase activity that was markedly stimulated by chromatin-associated proteins histone H1 and high mobility group proteins. DFF40 also triggered chromatin condensation when incubated with nuclei. These data suggest that DFF40 is sufficient to trigger both DNA fragmentation and chromatin condensation during apoptosis.
Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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Liu
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Li
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Widlak
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Zou
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Luo
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Garrard
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Wang
D000595:Amino Acid Sequence; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D002843:Chromatin / Q000378:metabolism*; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D051017:Apoptosis Regulatory Proteins; D002843:Chromatin; D047908:Intracellular Signaling Peptides and Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C109664:caspase-activated DNase inhibitor; C113696:DFFB protein, human; D003851:Deoxyribonucleases