PARP CLEAVAGE IN THE APOPTOTIC PATHWAY IN S2 CELLS FROM DROSOPHILA-MELANOGASTER

Caspase activities and two cDNA sequences have been identified in Dros ophila melanogaster. To study the molecular events following the activ ation of the apoptotic pathway in D. melanogaster, S2 cells were treat ed with etoposide and the timing of the apoptotic events, such as casp ase activation, mitochondrial pore opening, and loss of membrane asymm etry, was determined. Poly(ADP-ribose) polymerase (PARP) is known to b e cleaved in the early phase of apoptosis in vertebrate systems. Littl e is known about the involvement of PARP cleavage in apoptosis in inve rtebrates. If PARP inactivation is a general event, this could mean th at DNA repair enzymes need to be cleaved for the death pathway to be c ompleted. We have found that in etoposide treated cells, PARP protein is processed, but the nature of the cleavage is not known. Further exp eriments must be conducted and the peptide fragments must be sequenced to relate protease activities with PARP cleavage.