The Npro product of classical swine fever virus interacts with IkappaBalpha, the NF-kappaB inhibitor.
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.
Doceul
Virginie
V
BBSRC Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK.
Charleston
Bryan
B
BBSRC Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK.
Crooke
Helen
H
Veterinary Laboratories Agency, New Haw, Addlestone, Surrey KT15 3NB, UK.
Reid
Elizabeth
E
BBSRC Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK.
Powell
Penny P
PP
BBSRC Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK.
Seago
Julian
J
BBSRC Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK.
D000818:Animals; D002460:Cell Line; D006692:Classical Swine Fever Virus / Q000378:metabolism* / Q000502:physiology; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism*; D007668:Kidney / Q000166:cytology / Q000821:virology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000378:metabolism*
D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D014764:Viral Proteins; D000072000:NF-KappaB Inhibitor alpha; D010450:Endopeptidases; C505229:N(pro) protein, swine fever virus