Abstract: The invention provides methods and compositions relating to DNA Fragmentation Factor (DFF) polypeptides and related nucleic acids. The polypeptides may be produced recombinantly from transformed host cells from the disclosed DFF encoding nucleic acids or purified from human cells. The invention provides isolated DFF hybridization probes and primers capable of specifically hybridizing with the disclosed DFF genes, DFF-specific binding agents such as specific antibodies, and methods of making and using the subject compositions in diagnosis, therapy and in the biopharmaceutical industry.

Abstract: A cell-free system based on the cytosol of normally growing cells, which reproduces measurable aspects of the apoptotic program, is provided. The apoptotic program is initiated by addition of dATP in the specific exemplification of the HeLa 100,000×g supernatant. Fractionation of the cytosol yielded a 15 kDa protein, identified by absorption spectrum and protein sequence as cytochrome c, that is required for in vitro apoptosis. Elimination of cytochrome c from cytosol by immunodepleticn or inclusion of sucrose to stabilize mitochondria during cytosol preparation, diminished the apoptotic activity. Addition of exogenous cytochrome c to cytochrome c-depleted extracts restored apoptotic activity. Cells undergoing apoptosis in vivo showed increased release of cytochrome c to their cytosol, suggesting that mitochondria may function in apoptosis by releasing cytochrome c.

Abstract: The invention provides methods and compositions relating to DNA Fragmentation Factor (DFF) polypeptides and related nucleic acids. More particularly, the present invention provides the sequence for the active subunit of DFF. The polylpeptides may be produced recombinantly from host cells transformed from the disclosed DFF encoding nucleic acids or purified from human cells. The invention provides isolated DFF hybridization probes and primers capable of specifically hybridization with the disclosed DFF genes, DFF-specific binding agents such as specific antibodies, and methods of making and using the subject compositions.