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Bruning-Richardson, Anke/0000-0002-9862-9805; Mertens, Peter/0000-0002-3438-3738 WOS:000327877200004 PubMed: 24165208 Background: Bluetongue virus (BTV) is an arbovirus that is responsible for 'bluetongue', an economically important disease of livestock. Although BTV is well characterised at the protein level, less is known regarding its interaction with host cells. During studies of virus inclusion body formation we observed what appeared to be a large proportion of cells in mitosis. Although the modulation of the cell cycle is well established for many viruses, this was a novel observation for BTV. We therefore undertook a study to reveal in more depth the impact of BTV upon cell division. Methods: We used a confocal microscopy approach to investigate the localisation of BTV proteins in a cellular context with their respective position relative to cellular proteins. In addition, to quantitatively assess the frequency of aberrant mitosis induction by the viral non-structural protein (NS) 2 we utilised live cell imaging to monitor HeLa-mCherry tubulin cells transfected with a plasmid expressing NS2. Results: Our data showed that these 'aberrant mitoses' can be induced in multiple cell types and by different strains of BTV. Further study confirmed multiplication of the centrosomes, each resulting in a separate mitotic spindle during mitosis. Interestingly, the BTV NS1 protein was strongly localised to the centrosomal regions. In a separate, yet related observation, the BTV NS2 protein was co-localised with the condensed chromosomes to a region suggestive of the kinetochore. Live cell imaging revealed that expression of an EGFP-NS2 fusion protein in HeLa-mCherry tubulin cells also results in mitotic defects. Conclusions: We hypothesise that NS2 is a microtubule cargo protein that may inadvertently disrupt the interaction of microtubule tips with the kinetochores during mitosis. Furthermore, the BTV NS1 protein was distinctly localised to a region encompassing the centrosome and may therefore be, at least in part, responsible for the disruption of the centrosome as observed in BTV infected mammalian cells. BBSRC and DefraUK Research & Innovation (UKRI)Biotechnology and Biological Sciences Research Council (BBSRC); Biotechnology and Biological Sciences Research CouncilUK Research & Innovation (UKRI)Biotechnology and Biological Sciences Research Council (BBSRC) [BBS/E/I/00001720] Funding Source: researchfish The authors are grateful for the funding provided by the BBSRC and Defra.

The aim of this study was to develop a polymerase chain reaction for specific detection of influenza A, B, and C RNA genomes. Three primer sets were selected from conserved regions of the genome coding for the non-structural proteins and were tested on 61 influenza A (22 H1N1, 9 H2N2, and 30 H3N2), 11 influenza B, and three influenza C isolates. Specific amplified products were obtained with all these strains after electrophoresis on a 2% agarose gel. The specificity of the reaction was increased by hybridization with oligonucleotide probes. When nucleic acids from a variety of micro-organisms from the respiratory tract were subjected to the PCR with these primers, no specific amplified products were generated. The sensitivity of the technique was found to be at the subpicogram level. The RNA-PCR was applied to 21 clinical specimens from patients with a culture/IF proven influenza infection. Six influenza A positive patients and 13 influenza B positive patients could be confirmed in the RNA-PCR. In two cases, influenza B positive IF specimens were found negative by the PCR. No virus could be isolated on eggs or tissue culture from these samples. RNA-PCR is a specific and sensitive technique for the detection of influenza virus genomes.

Flaviviral NS3 is a multifunctional protein displaying N-terminal protease activity in addition to C-terminal helicase, nucleoside 5'-triphosphatase (NTPase), and 5'-terminal RNA triphosphatase (RTPase) activities. NS3 is held to support the separation of RNA daughter and template strands during viral replication. In addition, NS3 assists the initiation of replication by unwinding the RNA secondary structure in the 3' non-translated region (NTR). We report here the three-dimensional structure (at 3.1 angstrom resolution) of the NS3 helicase domain (residues 186-619; NS3:186-619) from Kunjin virus, an Australian variant of the West Nile virus. As for homologous helicases, NS3:186-619 is composed of three domains, two of which are structurally related and held to host the NTPase and RTPase active sites. The third domain (C-terminal) is involved in RNA binding/ recognition. The NS3:186-619 construct occurs as a dimer in solution and in the crystals. We show that NS3:186-619 displays both ATPase and RTPase activities, that it can unwind a double-stranded RNA substrate, being however inactive on a double-stranded DNA substrate. Analysis of different constructs shows that full length NS3 displays increased helicase activity, suggesting that the protease domain plays an assisting role in the RNA unwinding process. The structural interaction between the helicase and protease domain has been assessed using small angle X-ray scattering on full length NS3, disclosing that the protease and helicase domains build a rather elongated molecular assembly differing from that observed in the NS3 protein from hepatitis C virus. (C) 2007 Elsevier Ltd. All rights reserved.