The Drosophila Bcl-2 family member dBorg-1 functions in the apoptotic response to UV-irradiation

As with all metazoans, the fly makes extensive use of selective programmed cell death (PCD) to remove excess cells and properly sculpt developing tissues. Several core components of the cell death machinery have been identified in flies, including caspases and an Apaf-1 ortholog [1-4], One missing component has been a member of the Bcl-2 family of proteins, which act either pro- or anti-apoptotically as upstream regulatory proteins. Here, we report the identification of Bcl-2 family members in Drosophila - dBorg-1 (Drosophila Bcl-2 ortholog), also identified by Igaki et al. [5], and dBorg-2. Removal of dBorg-1 function during Drosophila embryonic development resulted in excess glial cells, demonstrating its pro-apoptotic function. In cell culture assays, dBorg-1 efficiently induced apoptosis but, remarkably, also demonstrated protective activity when death stimuli were introduced, Finally, ectopic expression of dBorg-1 in the eye led to subtle defects that were strongly potentiated by ultra violet (UV) irradiation, resulting in a dramatic loss of retinal cells.