Reovirus-induced apoptosis requires activation of transcription factor NF-kappaB.
Reovirus infection induces apoptosis in cultured cells and in vivo. To identify host cell factors that mediate this response, we investigated whether reovirus infection alters the activation state of the transcription factor nuclear factor kappa B (NF-kappaB). As determined in electrophoretic mobility shift assays, reovirus infection of HeLa cells leads to nuclear translocation of NF-kappaB complexes containing Rel family members p50 and p65. Reovirus-induced activation of NF-kappaB DNA-binding activity correlated with the onset of NF-kappaB-directed transcription in reporter gene assays. Three independent lines of evidence indicate that this functional form of NF-kappaB is required for reovirus-induced apoptosis. First, treatment of reovirus-infected HeLa cells with a proteasome inhibitor prevents NF-kappaB activation following infection and substantially diminishes reovirus-induced apoptosis. Second, transient expression of a dominant-negative form of IkappaB that constitutively represses NF-kappaB activation significantly reduces levels of apoptosis triggered by reovirus infection. Third, mutant cell lines deficient for either the p50 or p65 subunits of NF-kappaB are resistant to reovirus-induced apoptosis compared with cells expressing an intact NF-kappaB signaling pathway. These findings indicate that NF-kappaB plays a significant role in the mechanism by which reovirus induces apoptosis in susceptible host cells.
Connolly
J L
JL
Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Rodgers
S E
SE
Clarke
P
P
Ballard
D W
DW
Kerr
L D
LD
Tyler
K L
KL
Dermody
T S
TS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009097:Multienzyme Complexes / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D012087:Reoviridae / Q000502:physiology*; D014779:Virus Replication
D015853:Cysteine Proteinase Inhibitors; D009097:Multienzyme Complexes; D016328:NF-kappa B; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex