Involvement of poly(ADP-ribose) polymerase and activation of caspase-3-like protease in heat shock-induced apoptosis in tobacco suspension cells.
The cleavage of poly(ADP-ribose) polymerase (PARP) by caspase (casp)-3 is an essential link in the apoptotic pathway in animal cells. In plant cells, however, there is no authentic evidence for the similar role that PARP may play during apoptosis. Using a heat shock (HS)-induced apoptosis system of tobacco cells, we found that immediately after a 4 h heat treatment, PARP was cleaved to form an 89 kDa signature fragment, while DNA laddering appeared only after a 20 h recovery following the HS. An activation of casp-3-like protease was also observed. The results suggest that apoptosis in plants and animals may share common mechanisms. On the other hand, when cells were preincubated with 4 mM 3-aminobenzamide or 2-8 mM nicotinamide, the specific inhibitors of PARP, before HS treatment, apoptotic cell death was reduced significantly. Our results thus imply that PARP may also be involved in apoptosis in a different way from the casp-related events.
Tian
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Department of Biology, Tsinghua University, 100084, Beijing, China.
Zhang
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Yan
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Dai
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YR
D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides / Q000494:pharmacology; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006358:Hot Temperature; D009536:Niacinamide / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D010947:Plants, Toxic; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D014026:Nicotiana / Q000166:cytology*
D001549:Benzamides; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D009536:Niacinamide; C025160:3-aminobenzamide; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D020169:Caspases