The Npro product of classical swine fever virus interacts with IkappaBalpha, the NF-kappaB inhibitor

Virginie Doceul, Bryan Charleston, Helen Crooke, Elizabeth Reid, Penny Powell, Julian Seago

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Classical swine fever virus (CSFV) belongs to the genus Pestivirus and is the causative agent of classical swine fever, a haemorrhagic disease of pigs. The virus replicates in host cells without activating interferon (IFN) production and has been reported to be an antagonist of double-stranded RNA-induced apoptosis. The N-terminal protease (N(pro)) of CSFV is responsible for this evasion of the host innate immune response. In order to identify cellular proteins that interact with the N(pro) product of CSFV, a yeast two-hybrid screen of a human library was carried out, which identified IkappaBalpha, the inhibitor of NF-kappaB, a transcription factor involved in the control of apoptosis, the immune response and IFN production. The N(pro)-IkappaBalpha interaction was confirmed using yeast two-hybrid analysis and additional co-precipitation assays. It was also shown that N(pro) localizes to both the cytoplasmic and nuclear compartments in stably transfected cells and in CSFV-infected cells. Following stimulation by tumour necrosis factor alpha, PK-15 cell lines expressing N(pro) exhibited transient nuclear accumulation of pIkappaBalpha, but no effect of CSFV infection on IkappaBalpha localization or NF-kappaB p65 activation was observed.
Original languageEnglish
Pages (from-to)1881-1889
Number of pages9
JournalJournal of General Virology
Issue number8
Publication statusPublished - Aug 2008


  • NF-kappa B
  • Animals
  • Viral Proteins
  • Humans
  • Two-Hybrid System Techniques
  • I-kappa B Proteins
  • Kidney
  • Endopeptidases
  • Cell Line
  • Classical swine fever virus

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