CAENORHABDITIS-ELEGANS ANTI-APOPTOTIC GENE CED-9 PREVENTS CED-3-INDUCED CELL-DEATH IN DROSOPHILA CELLS

ced-9, a member of the bcl-2 gene family in Caenorhabditis elegans pla ys a central roles in preventing cell death in norms. Overexpression o f human bcl-2 can partially prevent cell death in C. elegans. However, it remains to be elucidated whether ced-9 can regulate cell death whe n expressed in other organisms. We demonstrated that the CED-9 protein is co-localized with BCL-2 in COS cells and Drosophila Schneider's L2 (SL2) cells, suggesting that the site of CED-9 action is located to s pecific cytoplasmic compartments. Overexpression of ced-9 only poorly protected cells from the death induced by ced-3 in HeLa cells, but ced -9 significantly reduced the cell death induced by ced-3 in Drosophila SL2 cells. Furthermore, apoptosis of SL2 cells that was induced by a Drosophila cell-death gene, reaper, was shown to be partially prevente d by ced-9, bcl-2 and bcl-xL. These results suggest that the signaling pathway that is required for the anti-apoptotic function of bcl-2 fam ily members, including ced-9, is conserved in Drosophila cells. In add ition, SL2 cells provide a unique systems for dissecting the main mach inery of cell death.