I Spy in the Developing Fly a Multitude of Ways to Die

Abstract

Cell proliferation and cell death are two opposing, yet complementary fundamental processes in development. Cell proliferation provides new cells, while developmental programmed cell death adjusts cell numbers and refines structures as an organism grows. Apoptosis is the best-characterized form of programmed cell death; however, there are many other non-apoptotic forms of cell death that occur throughout development. Drosophila is an excellent model for studying these varied forms of cell death given the array of cellular, molecular, and genetic techniques available. In this review, we discuss select examples of apoptotic and non-apoptotic cell death that occur in different tissues and at different stages of Drosophila development. For example, apoptosis occurs throughout the nervous system to achieve an appropriate number of neurons. Elsewhere in the fly, non-apoptotic modes of developmental cell death are employed, such as in the elimination of larval salivary glands and midgut during metamorphosis. These and other examples discussed here demonstrate the versatility of Drosophila as a model organism for elucidating the diverse modes of programmed cell death.

Ecdysone controlled cell and tissue deletion

“…Ecdysone signaling through EcR-B1 is required for the survival of the nurse and folicle cells until late oogenesis [126]. At the end of oogenesis, nurse cells "dump" their cytoplasmic contents into the oocyte and undergo cell death [127]. To date, the mechanism of this cell death remains unclear as it is not prevented by blocking apoptosis or autophagy [127].…”

“…At the end of oogenesis, nurse cells "dump" their cytoplasmic contents into the oocyte and undergo cell death [127]. To date, the mechanism of this cell death remains unclear as it is not prevented by blocking apoptosis or autophagy [127]. The follicle cells also undergo death, in some cases this is via apoptosis [128].…”

Coordinating Proliferation, Polarity, and Cell Fate in the Drosophila Female Germline

“…The process of nurse cell dumping streams contents of the nurse cell cytoplasm into the oocyte at Stage 10 (reviewed in Quinlan, 2016). At this stage, nurse cells enter programed cell death and gradually shrink in size through the remaining stages of oogenesis (reviewed in Peterson et al, 2015;Yalonetskaya et al, 2018).…”

Cell death during complete metamorphosis

“…Although tissue remodelling involving cell death processes has been reported in many species that undergo complete metamorphosis, Lepidoptera and the dipteran D. melanogaster have provided the bulk of information on these processes and have made it possible to unravel the underlying regulatory mechanisms. Recent reviews describe in detail PCD during metamorphosis in Drosophila tissues and organs [7,[10][11][12]. By contrast, a comprehensive description of the processes and regulatory mechanisms involved in tissue reshaping in Lepidoptera is lacking.…”