Luis Alberto Baena-Lopez

Abstract Caspases are best known for promoting apoptosis, yet their role in tissue regeneration by compensatory proliferation remains unclear. Using Drosophila wing discs and a delayed reporter for the initiator caspase-9 ortholog Dronc activity, we identify two apoptosis-resistant epithelial cell populations that mediate regeneration after ionizing radiation: Dronc-activating (DARE) and non-activating (NARE) cells.

1 Introduction When cellular homeostasis is impaired, affected cells may limit the damage by inducing either cellular arrest or cell death. Best characterized in this context is the tumor suppressor p53, which—depending on the amount of DNA damage or other forms of cellular stress—induces cellular senescence, apoptosis, or alternative forms of cell death (1–3). Collectively or individually, these responses will prevent malfunction at the tissue/organ and organismic levels.