Two domains of the V protein of virulent canine distemper virus selectively inhibit STAT1 and STAT2 nuclear import

Canine distemper virus (CDV) causes in dogs a severe systemic infection, with a high frequency of demyelinating encephalitis. Among the six genes transcribed by CDV, the P gene encodes the polymerase cofactor protein (P) as well as two additional nonstructural proteins, C and V; of these V was shown to act as a virulence factor. We investigated the molecular mechanisms by which the P gene products of the neurovirulent CDV A75/17 strain disrupt type I interferon (IFN-alpha/beta)-induced signaling that results in the establishment of the antiviral state. Using recombinant knockout A75/17 viruses, the V protein was identified as the main antagonist of IFN-alpha/beta-mediated signaling. Importantly, immunofluorescence analysis illustrated that the inhibition of IFN-alpha/beta-mediated signaling correlated with impaired STAT1/STAT2 nuclear import, whereas the phosphorylation state of these proteins was not affected. Coimmunoprecipitation assays identified the N-terminal region of V (VNT) responsible for STAT1 targeting, which correlated with its ability to inhibit the activity of the IFN-alpha/beta-mediated antiviral state. Conversely, while the C-terminal domain of V (VCT) could not function autonomously, when fused to VNT it optimally interacted with STAT2 and subsequently efficiently suppressed the IFN-alpha/beta-mediated signaling pathway. The latter result was further supported by a single mutation at position 110 within the VNT domain of CDV V protein, resulting in a mutant that lost STAT1 binding while retaining a partial STAT2 association. Taken together, our results identified the CDV VNT and VCT as two essential modules that complement each other to interfere with the antiviral state induced by IFN-alpha/beta-mediated signaling. Hence, our experiments reveal a novel mechanism of IFN-alpha/beta evasion among the morbilliviruses.

Investigation of a unique short open reading frame within the 3' untranslated region of the canine distemper virus matrix messenger RNA

Increasing evidence suggest that the long "untranslated" region (UTR) between the matrix (M) and the fusion (F) proteins of morbilliviruses has a functional role. In canine distemper virus (CDV), the F 5' UTR was recently shown to code for a long F signal peptide (Fsp). Subsequently, it was reported that the M/F UTRs combined with the long Fsp were synergistically regulating the F mRNA and protein expression, thereby modulating virulence. Unique to CDV, a short putative open reading frame (ORF) has been identified within the wild-type CDV-M 3' UTR (termed M2). Here, we investigated whether M2 was expressed from the genome of the virulent and demyelinating A75/17-CDV strain. An expression plasmid encoding the M2 ORF tagged both at its N-terminal (HA) and C-terminal domains (RFP), was first constructed. Then, a recombinant virus with its putative M2 ORF replaced by HA-M2-RFP was successfully recovered from cDNA (termed recA75/17(green)-HA-M2-RFP). M2 expression in cells transfected or infected with these mutants was studied by immunoprecipitation, immunofluorescence, immunoblot and flow cytometry analyses. Although fluorescence was readily detected in HA-M2-RFP-transfected cells, absence of red fluorescence emission in several recA75/17(green)-HA-M2-RFP-infected cell types suggested lack of M2 biosynthesis, which was confirmed by the other techniques. Consistent with these data, no functional role of the short polypeptide was revealed by infecting various cell types with HA-M2-RFP over-expressing or M2-knockout recombinant viruses. Thus, in sharp contrast to the CDV-F 5' UTR reported to translate a long Fsp, our data provided evidence that the CDV-M 3' UTR does not express any polypeptides.

Suspected paradoxical nerve root signature in a dog with right-sided intervertebral lumbar disk extrusion: a case report

A 7 year old male mongrel dog was presented with a 3 weeks history of gait disturbance in the pelvic limbs more pronounced on the left side associated with pain in the lumbar spine. At presentation neurologic deficits consisted of mild bilateral proprioceptive deficits and nerve root signature in the left pelvic limb. A large intervertebral disc herniation L3-L4 located in a right ventrolateral area of the spinal canal was diagnosed by magnetic resonance imaging. The herniated disc was removed through right hemilaminectomy and fenestration. The dog recovered quickly and returned to the owners 4 days after surgery with a slight lameness in the left pelvic limb. On the follow-up examination 2 months later the dog showed normal gait and normal neurological examination. Nerve root signature is not always indicative for the side of the lesion in case of lateralized intervertebral disc herniation

Temporal factors in violence related injuries--An 11 year trend analysis of violence-related injuries from a Swiss Emergency Department

Injury from interpersonal violence is a major social and medical problem in the industrialized world. Little is known about the trends in prevalence and injury pattern or about the demographic characteristics of the patients involved.

Acute health problems in African refugees: ten years' experience in a Swiss emergency department

Over the last two decades, the total number of applications from Africans for asylum in the countries of the European Union has increased from 578,000 to more than 2.9 million. About 20 % (7,196/36,100) of the asylum seekers in Switzerland originate from Africa. The disease profile of African asylum seekers is remarkably different from that of the native population in the country of application. We have therefore conducted an analysis of African asylum seekers presenting themselves to our emergency department.