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 tiss ues. Several core components of the cell death machinery have been identifi ed in flies, including caspases and an Apaf-1 ortholog [1-4], One missing c omponent has been a member of the Bcl-2 family of proteins, which act eithe r pro- or anti-apoptotically as upstream regulatory proteins. Here, we repo rt the identification of Bcl-2 family members in Drosophila - dBorg-1 (Dros ophila Bcl-2 ortholog), also identified by Igaki et al. [5], and dBorg-2. R emoval of dBorg-1 function during Drosophila embryonic development resulted in excess glial cells, demonstrating its pro-apoptotic function. In cell c ulture assays, dBorg-1 efficiently induced apoptosis but, remarkably, also demonstrated protective activity when death stimuli were introduced, Finall y, ectopic expression of dBorg-1 in the eye led to subtle defects that were strongly potentiated by ultra violet (UV) irradiation, resulting in a dram atic loss of retinal cells.