Abstract
Nuclear factor-κB (NF-κB) is a transcription factor that plays an important role in the immune system and cell death. Many viral proteins modulate NF-κB to escape host immune surveillance, promote cell survival, and enhance viral replication. In the present study, we show that NF-κB activity is downmodulated by viral interferon regulatory factor 3 (vIRF3), which is encoded by Kaposi's sarcoma-associated herpesvirus open-reading frame K10.5. vIRF3 repressed NF-κB-dependent transcription in a dose-dependent manner and inhibited the activation of NF-κB induced by tumor necrosis factor (TNF)-α. In vivo studies showed vIRF3 inhibited IκB kinase β (IKKβ) activity, but not IKKα activity, resulting in reduced IκB phosphorylation. Immunofluorescence assays showed that vIRF3 interfered with nuclear translocation of NF-κB. In addition, consistent with the inhibition of NF-κB activity, vIRF3 sensitized cells to TNF-α-induced apoptosis. While vIRF3 interacts with IKKβ in vitro and in 293T cells, we were unable to demonstrate vIRF3-IKKβ interaction in BCBL-1 cells. Our results indicate that vIRF3 can regulate the host immune system and apoptosis via inhibition of NF-κB activity.
Original language | English |
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Pages (from-to) | 6146-6155 |
Number of pages | 10 |
Journal | Oncogene |
Volume | 23 |
Issue number | 36 |
DOIs | |
State | Published - 12 Aug 2004 |
Keywords
- IKK
- KSHV
- NF-κB
- VIRF3