Rapid activation of poly(ADP-ribose) polymerase contributes to Sindbis virus and staurosporine-induced apoptotic cell death.
Poly(ADP-ribose) polymerase-1 (PARP-1) is a chromatin-associated enzyme that is activated by DNA strand breaks and catalyzes the transfer of ADP-ribose groups from NAD to itself and other nuclear proteins. Although caspase-mediated PARP-1 cleavage occurs during almost all forms of apoptosis, the contribution of PARP-1 activation and cleavage to this cell death process remains unclear. Using immortalized fibroblasts from wild-type (PARP-1(+/+)) and PARP-1 knockout (PARP-1(-/-)) mice, and a mouse neuroblastoma cell line (N18), the role that poly(ADP-ribosyl)ation plays in Sindbis virus (SV)-induced apoptosis was examined. Robust PARP-1 activation occurred in SV-infected cells prior to morphologic changes associated with apoptotic cell death and PARP-1 activity ceased simultaneously with caspase-3 activation and PARP-1 proteolysis. PARP-1 activity was maximal before detectable DNA fragmentation, but was absent when DNA damage was most intense. SV and staurosporine-induced cell death was delayed in fibroblasts lacking PARP-1 activity, suggesting that PARP-1 activation contributes to apoptotic cell death induced by these stimuli. SV replication was not affected by lack of PARP-1 activity, but DNA fragmentation and caspase-3 activation were delayed and occurred at lower levels in PARP-1-deficient fibroblasts. Early virus-induced PARP-1 activation may represent a novel way by which cells signal to the nucleus to regulate protein function by poly(ADP-ribosyl)ation in response to virus infection.
Nargi-Aizenman
Jennifer L
JL
W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns hopkins University, Baltimore, Maryland 21205, USA.
Simbulan-Rosenthal
Cynthia M
CM
Kelly
Tara A
TA
Smulson
Mark E
ME
Griffin
Diane E
DE
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D051379:Mice; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology*; D012845:Sindbis Virus / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology*; D014779:Virus Replication
D004791:Enzyme Inhibitors; D011065:Poly(ADP-ribose) Polymerases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine