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PARP cleavage in the apoptotic pathway in S2 cells from Drosophila melanogaster
P Poltronieri1, T Yokota, Y Koyama
1Department of Biochemistry, Institute of Basic Medical Sciences, Tennoudai, Tsukuba, Japan. miro@md.tsukuba.ac.jp
Abstract:
Caspase activities and two cDNA sequences have been identified in Drosophila melanogaster. To study the molecular events following the activation of the apoptotic pathway in D. melanogaster, S2 cells were treated with etoposide and the timing of the apoptotic events, such as caspase activation, mitochondrial pore opening, and loss of membrane asymmetry, was determined. Poly(ADP-ribose) polymerase (PARP) is known to be cleaved in the early phase of apoptosis in vertebrate systems. Little is known about the involvement of PARP cleavage in apoptosis in invertebrates. If PARP inactivation is a general event, this could mean that DNA repair enzymes need to be cleaved for the death pathway to be completed. We have found that in etoposide-treated cells, PARP protein is processed, but the nature of the cleavage is not known. Further experiments must be conducted and the peptide fragments must be sequenced to relate protease activities with PARP cleavage.
Insights
This study investigated apoptosis in Drosophila melanogaster, finding that Poly(ADP-ribose) polymerase (PARP) protein is processed during programmed cell death. Further research is needed to understand the exact nature of this PARP cleavage in invertebrates.
Area of Science:
- Molecular biology
- Cell biology
- Genetics
Background:
- Apoptosis, or programmed cell death, is a crucial biological process.
- Caspase activation is a hallmark of apoptosis in many organisms.
- Poly(ADP-ribose) polymerase (PARP) cleavage is an early event in vertebrate apoptosis, but its role in invertebrates is unclear.
Purpose of the Study:
- To investigate the molecular events of apoptosis in Drosophila melanogaster.
- To determine the timing of caspase activation and other apoptotic events.
- To explore the involvement and nature of PARP cleavage in invertebrate apoptosis.
Main Methods:
- Drosophila melanogaster S2 cells were treated with etoposide to induce apoptosis.
- Apoptotic events including caspase activation, mitochondrial pore opening, and membrane asymmetry loss were monitored.
- PARP protein processing was analyzed in treated cells.
Main Results:
- Etoposide treatment induced apoptosis in D. melanogaster S2 cells.
- Key apoptotic events were timed following etoposide exposure.
- PARP protein was found to be processed in etoposide-treated cells, though the specific cleavage mechanism remains unknown.
Conclusions:
- PARP processing occurs during etoposide-induced apoptosis in Drosophila.
- The precise nature of PARP cleavage in invertebrates requires further investigation.
- Understanding PARP cleavage in Drosophila may shed light on conserved mechanisms of apoptosis and DNA repair.