Abstract
We have identified and purified from HeLa cytosol a protein that induces DNA fragmentation in coincubated nuclei after it is activated by caspase-3. This protein, designated DNA Fragmentation Factor (DFF), is a heterodimer of 40 kDa and 45 kDa subunits. The amino acid sequence of the 45 kDa subunit, determined from its cDNA sequence, reveals it to be a novel protein. Caspase-3 cleaves the 45 kDa subunit at two sites to generate an active factor that produces DNA fragmentation without further requirement for caspase-3 or other cytosolic proteins. In cells undergoing apoptosis, the 45 kDa subunit is cleaved in the same pattern as it is cleaved by caspase-3 in vitro. These data delineate a direct signal transduction pathway during apoptosis: caspase-3 to DFF to DNA fragmentation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Apoptosis / physiology
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Apoptosis Regulatory Proteins
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Caspase 3
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Caspases*
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Cell Line
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Cloning, Molecular
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Cricetinae
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Cysteine Endopeptidases / metabolism*
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Cytosol / chemistry
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DNA Fragmentation*
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DNA, Complementary / genetics
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Dimerization
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HeLa Cells / chemistry
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Humans
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Lamins
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Liver
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Molecular Sequence Data
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Molecular Weight
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Monocytes / cytology
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Nuclear Proteins / metabolism
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Proteins / chemistry
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Proteins / genetics
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Proteins / isolation & purification*
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Proteins / metabolism
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Proteins / physiology*
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Sequence Analysis
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Signal Transduction / physiology
Substances
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Apoptosis Regulatory Proteins
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DNA, Complementary
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Lamins
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Nuclear Proteins
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Proteins
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caspase-activated DNase inhibitor
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CASP3 protein, human
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Caspase 3
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Caspases
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Cysteine Endopeptidases