The ABC Transporter Promotes Cell Clearance in the Ovary.

The clearance of dead cells is a fundamental process in the maintenance of tissue homeostasis. Genetic studies in , , and mammals have identified two evolutionarily conserved signaling pathways that act redundantly to regulate this engulfment process: the and pathways. Of these engulfment genes, only the ortholog remains to be identified in Homology searches have revealed a family of putative homologs encoding ATP-binding cassette (ABC) transporters in To determine which of these genes functions similarly to , we analyzed mutants for engulfment phenotypes in oogenesis, during which nurse cells (NCs) in each egg chamber undergo programmed cell death (PCD) and are removed by neighboring phagocytic follicle cells (FCs). Our genetic analyses indicate that one of the ABC transporter genes, which we have named (Engulfment ABC Transporter in the ovary), is required for NC clearance in the ovary and acts in the same pathways as , the ortholog, and in parallel to in the FCs. Additionally, we show that acts in the FCs to promote accumulation of the transmembrane receptor Drpr, and promote membrane extensions around the NCs for their clearance. Since ABCA class transporters, such as CED-7 and ABCA1, are known to be involved in lipid trafficking, we propose that Eato acts to transport membrane material to the growing phagocytic cup for cell corpse clearance. Our work presented here identifies as the ortholog in , and demonstrates a role for in Drpr accumulation and phagocytic membrane extensions during NC clearance in the ovary.