Cell-autonomous requirement for DNaseII in non-apoptotic cell death

摘要

DNA fragmentation is a critical component of apoptosis but it has not been characterized in non-apoptotic forms of cell death, such as necrosis and autophagic cell death. In mammalian apoptosis, caspase activated DNase (CAD) cleaves DNA into nucleosomal fragments in dying cells, and subsequently DNaseII, an acid nuclease, completes the DNA degradation but acts non-cell-autonomously within lysosomes of engulfing cells. Here we examine the requirement for DNases during two examples of programmed cell death (PCD) that occur in the Drosophila melanogaster ovary, starvation-induced death of mid-stage egg chambers and developmental nurse cell death in late oogenesis. Surprisingly, we found that DNaseII was required cell-autonomously in nurse cells during developmental PCD, indicating that it acts within dying cells. Dying nurse cells contain autophagosomes, indicating that autophagy may contribute to these forms of PCD. Furthermore, we provide evidence that developmental nurse cell PCD in late oogenesis shows hallmarks of necrosis. These findings indicate that DNaseII can act cell-autonomously to degrade DNA during non-apoptotic cell death.