Competing death programs in poliovirus-infected cells: commitment switch in the middle of the infectious cycle.
Productive poliovirus infection of HeLa cells leads to the canonical cytopathic effect (CPE), whereas certain types of abortive infection result in apoptosis. To define the time course of commitment to the different types of poliovirus-induced death, inhibitors of viral replication (guanidine HCl) or translation (cycloheximide) were added at different times postinfection (p.i.). Early in the infection (during the first approximately 2 h p.i.), predominantly proapoptotic viral function was expressed, rendering the cells committed to apoptosis, which developed several hours after viral expression was arrested. In the middle of infection, concomitantly with the onset of fast generation of viral progeny, the implementation of the viral apoptotic program was abruptly interrupted. In particular, activation of an Asp-Glu-Val-Asp (DEVD)-specific caspase(s) occurring in the apoptosis-committed cells was prevented by the ongoing productive infection. Simultaneously, the cells retaining normal or nearly normal morphology became committed to CPE, which eventually developed regardless of whether or not further viral expression was allowed to proceed. The implementation of the poliovirus-induced apoptotic program was suppressed in HeLa cells overexpressing the Bcl-2 protein, indicating that the fate of poliovirus-infected cells depends on the balance of host and viral pro- and antiapoptotic factors.
Agol
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VI
M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, Moscow Region 142782, Russia. viago@ipive.genebee.msu.su
Belov
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GA
Bienz
K
K
Egger
D
D
Kolesnikova
M S
MS
Romanova
L I
LI
Sladkova
L V
LV
Tolskaya
E A
EA
D017209:Apoptosis / Q000187:drug effects; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression; D019254:Genes, bcl-2 / Q000235:genetics / Q000502:physiology; D019791:Guanidine / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D017955:Poliovirus / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D014176:Protein Biosynthesis / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D014779:Virus Replication / Q000187:drug effects
D061945:Caspase Inhibitors; D003513:Cycloheximide; D020169:Caspases; D019791:Guanidine