Emerybutcher1361

Overall, these findings agree well with those of previous biochemical studies and extend our understanding of the promoter sequence and the mechanism of RSV RNA synthesis.IMPORTANCE As a major human pathogen, RSV affects 3.4 million children worldwide annually. However, no effective antivirals or vaccines are available. An in-depth mechanistic understanding of the RSV RNA synthesis machinery remains a high priority among the NNS RNA viruses. There is a strong public health need for research on this virus, due to major fundamental gaps in our understanding of NNS RNA virus replication. As the key enzyme executing transcription and replication of the virus, the RSV RdRP is a logical target for novel antiviral drugs. Therefore, exploring the primer-dependent RNA elongation extends our mechanistic understanding of the RSV RNA synthesis. Further fine mapping of the promoter sequence paves the way to better understand the function and structure of the RSV polymerase.Genome segmentation is mainly thought to facilitate reassortment. Here, we show that segmentation can also allow differences in segment abundance in populations of bluetongue virus (BTV). BTV has a genome consisting in 10 segments, and its cycle primarily involves periodic alternation between ruminants and Culicoides biting midges. We have developed a reverse transcription-quantitative PCR (RT-qPCR) approach to quantify each segment in wild BTV populations sampled in both ruminants and midges during an epizootic. Segment frequencies deviated from equimolarity in all hosts. Interestingly, segment frequencies were reproducible and distinct between ruminants and biting midges. Beyond a putative regulatory role in virus expression, this phenomenon could lead to different evolution rates between segments.IMPORTANCE The variation in viral gene frequencies remains a largely unexplored aspect of within-host genetics. This phenomenon is often considered to be specific to multipartite viruses. Multipartite viruses have segmented genomes, but in contrast to segmented viruses, their segments are each encapsidated alone in a virion. A main hypothesis explaining the evolution of multipartism is that, compared to segmented viruses, it facilitates the regulation of segment abundancy, and the genes the segments carry, within a host. These differences in gene frequencies could allow for expression regulation. Here, we show that wild populations of a segmented virus, bluetongue virus (BTV), also present unequal segment frequencies. BTV cycles between ruminants and Culicoides biting midges. As expected from a role in expression regulation, segment frequencies tended to show specific values that differed between ruminants and midges. Our results expand previous knowledge on gene frequency variation and call for studies on its role and conservation beyond multipartite viruses.H7N9 influenza A virus (IAV) is an emerged contagious pathogen that may cause severe human infections, even death. Understanding the precise cross talk between virus and host is vital for the development of effective vaccines and therapeutics. In the present study, we identified the nucleoprotein (NP) of H7N9 IAV as a positive regulator of RIG-I like receptor (RLR)-mediated signaling. Based on a loss-of-function strategy, we replaced H1N1 (mouse-adapted PR8 strain) NP with H7N9 NP, by using reverse genetics, and found that the replication and pathogenicity of recombinant PR8-H7N9NP (rPR8-H7N9NP) were significantly attenuated in cells and mice. Biochemical and cellular analyses revealed that H7N9 NP specifically interacts with tumor necrosis factor receptor (TNFR)-associated factor 3 (TRAF3) after viral infection. Subsequently, we identified a PXXQXS motif in the H7N9 NP that may be a determinant for the NP and TRAF3 interaction. Furthermore, H7N9 NP stabilized TRAF3 expression via competitively binding to TRAs Lys48-linked polyubiquitination of TRAF3 for degradation. The current study revealed a novel mechanism by which H7N9 NP upregulates TRAF3-mediated type I interferon production, leading to attenuation of viral replication and pathogenicity in cells and mice. Our finding provides a possible explanation for virus and host commensalism via viral manipulation of the host immune system.Given the complex biology of human immunodeficiency virus (HIV) and its remarkable capacity to evade host immune responses, HIV vaccine efficacy may benefit from the induction of both humoral and cellular immune responses of maximal breadth, potency, and longevity. Guided by this rationale, we set out to develop an immunization protocol aimed at maximizing the induction of anti-Envelope (anti-Env) antibodies and CD8+ T cells targeting non-Env epitopes in rhesus macaques (RMs). Our approach was to deliver the entire simian immunodeficiency virus (SIV) proteome by serial vaccinations. To that end, 12 RMs were vaccinated over 81 weeks with DNA, modified vaccinia Ankara (MVA), vesicular stomatitis virus (VSV), adenovirus type 5 (Ad5), rhesus monkey rhadinovirus (RRV), and DNA again. selleckchem Both the RRV and the final DNA boosters delivered a near-full-length SIVmac239 genome capable of assembling noninfectious SIV particles and inducing T-cell responses against all nine SIV proteins. Compared to previous SIV vaccine trials, the present DNA-MVA-VSV-Ad5-RRV-DNA regimen resulted in comparable levels of Env-binding antibodies and SIV-specific CD8+ T-cells. Interestingly, one vaccinee developed low titers of neutralizing antibodies (NAbs) against SIVmac239, a tier 3 virus. Following repeated intrarectal marginal-dose challenges with SIVmac239, vaccinees were not protected from SIV acquisition but manifested partial control of viremia. Strikingly, the animal with the low-titer vaccine-induced anti-SIVmac239 NAb response acquired infection after the first SIVmac239 exposure. Collectively, these results highlight the difficulties in eliciting protective immunity against immunodeficiency virus infection.IMPORTANCE Our results are relevant to HIV vaccine development efforts because they suggest that increasing the number of booster immunizations or delivering additional viral antigens may not necessarily improve vaccine efficacy against immunodeficiency virus infection.