Physiological apoptosis of polar cells during Drosophila oogenesis is mediated by Hid-dependent regulation of Diap1

Anne-Marie Pret (1) , Asma Khammari (1) , Francois Agnes (1) , Pierre Gandille (1)

1 Development and Cell Dynamics

Although much has been learned in recent years about the apoptotic machinery, the mechanisms underlying survival and death choices during development of metazoans remain less clearly understood. During early oogenesis in Drosophila, a small excess in the number of specialized somatic cells, called polar cells, produced at follicle extremities is reduced to exactly two cells through apoptosis by mid-oogenesis. We have found that polar cells destined to die first lose their apical contacts and then round-up and shrink progressively until they disappear. Caspases are activated only once the cells have begun to shrink suggesting that they are implicated in this part of the process but not in the initial loss of cell polarity. Loss of function analyses based on mutant, clonal and RNAi approaches show that among the RHG family of pro-apoptotic factors, Hid is specifically necessary for polar cell apoptosis, as well as the initiator caspase Dronc and its adaptor Dark/Apaf-1, and likely several effector caspases, in particular Drice. In addition, we show that Hid protein and transcripts accumulate specifically in polar cells destined to die, while the anti-apoptotic factor Diap1 is downregulated in these cells in a hid-dependent manner. Therefore, our results implicate the Hid-Diap1 module as an important regulatory point in a developmental case of apoptosis.

Mots clés: apoptosis; polar cells; diap1; Drosophila; hid

Anne-Marie Pret, Asma Khammari, Francois Agnes, Pierre Gandille. Physiological apoptosis of polar cells during Drosophila oogenesis is mediated by Hid-dependent regulation of Diap1. Cell Death and Differentiation, 2010, ⟨10.1038/cdd.2010.141⟩. ⟨hal-00595931⟩