An assay uses apoptotic nucleases to screen for apoptosis modulators, in a method of modulating apoptosis, and in a method of aiding in a diagnosis of a disease, among other methods. materials for use in the assay include isolated or recombinant polypeptides and polynucleotides, compositions comprising those isolated or recombinant polypeptides and polynucleotides, vectors, transgenic organisms, and integrated systems among other aspects.