Apoptosis Enhancing Nuclease (AEN)

AEN efficiently cleaved single-stranded, blunt end double-stranded, 3-prime recessed, and branched DNA, and less efficiently cleaved nicked and 5-prime recessed DNA. Experiments with AEN deletion mutants demonstrated that the exonuclease domain of AEN is crucial for its nuclease activity. Immunolocalization and cell fractionation experiments showed that AEN colocalizes with AIF (AIFM1) and CAD (DFFB) in the nucleus of irradiated cells. Transfection experiments demonstrated that expression of AEN acts to increase apoptosis 2-fold in the absence of irradiation and that cooperation exists between IR and AEN in apoptotic DNA degradation.AEN may contribute to radiation response during ionizing radiation-induced apoptosis by cooperatively cleaving DNA substrates along with other apoptotic nucleases and enhance apoptosis.