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Jayasundara Mudiyanselage Kanchana Ganga Kumari Jayasundara, Stephen William Walkden-Brown, Magaret Elizabeth Katz, A F M Fakhrul Islam, Katrin Gondola Renz, Jody McNally, Peter Hunt
Infectious bursal disease virus (IBDV) is endemic to most poultry-producing countries worldwide. Immunosuppressive classical and variant IBDV strains endemic to Australia are genetically distinct from other international strains. We report the results of infection experiments with Australian classical strain 06/95 and variant strain 02/95 in specific pathogen free (SPF) chickens. We tested the effects of strain and age of infection on bursal atrophy, viral RNA (vRNA) load in bursa of Fabricius (bursa), spleen, thymus, caecal tonsils, faeces, litter and exhaust dust as determined by real time reverse transcriptase polymerase chain reaction (qRT-PCR)...
October 21, 2016: Avian Pathology: Journal of the W.V.P.A
Seema S Lakdawala, Ervin Fodor, Kanta Subbarao
Influenza A viruses bear an eight-segmented single-stranded negative-sense RNA genome that is replicated in the nucleus. Newly synthesized viral RNA (vRNA) segments are exported from the nucleus and transported to the plasma membrane for packaging into progeny virions. Influenza viruses exploit many host proteins during these events, and this is the portion of the viral life cycle when genetic reassortment among influenza viruses occurs. Reassortment among influenza A viruses allows viruses to expand their host range, virulence, and pandemic potential...
September 29, 2016: Annual Review of Virology
Nilshad N Salim, Safder S Ganaie, Anuradha Roy, Subbiah Jeeva, Mohammad A Mir
An evolutionary conserved sequence at the 5' terminus of hantaviral genomic RNA plays an important role in viral transcription initiation and packaging of the viral genome into viral nucleocapsids. Interaction of viral nucleocapsid protein (N) with this conserved sequence facilitates mRNA translation by a unique N-mediated translation strategy. While this evolutionary conserved sequence facilitates virus replication with the assistance of N in eukaryotic hosts having multifaceted antiviral defense, we demonstrate its interaction with N presents a novel target for therapeutic intervention of hantavirus disease...
October 12, 2016: Journal of Biological Chemistry
Aidin Molouki, Ben Peeters
Since the first rescue of a recombinant Newcastle disease virus (rNDV) in the late 1990s, many more rNDVs have been rescued by researchers around the world. Regardless of methodology, the main principle behind rescue of the virus has remained the same, i.e., the formation of a functional replication complex by simultaneously providing the full-length viral RNA and the viral NP, P and L proteins. However, different strategies have been reported for the insertion of the full-length genome into a suitable transcription vector, which remains the most challenging step of the rescue...
October 1, 2016: Archives of Virology
Nicole C Robb, Aartjan J W Te Velthuis, Ralph Wieneke, Robert Tampé, Thorben Cordes, Ervin Fodor, Achillefs N Kapanidis
Influenza viruses have a segmented viral RNA (vRNA) genome, which is replicated by the viral RNA-dependent RNA polymerase (RNAP). Replication initiates on the vRNA 3' terminus, producing a complementary RNA (cRNA) intermediate, which serves as a template for the synthesis of new vRNA. RNAP structures show the 3' terminus of the vRNA template in a pre-initiation state, bound on the surface of the RNAP rather than in the active site; no information is available on 3' cRNA binding. Here, we have used single-molecule Förster resonance energy transfer (smFRET) to probe the viral RNA conformations that occur during RNAP binding and initial replication...
September 30, 2016: Nucleic Acids Research
Agnieszka Ruszkowska, Elzbieta Lenartowicz, Walter N Moss, Ryszard Kierzek, Elzbieta Kierzek
The influenza A virus genome is comprised of eight negative-sense viral (v)RNA segments. The seventh segment of the genome encodes two essential viral proteins and is specifically packaged alongside the other seven vRNAs. To gain insight into the possible roles of RNA structure both within and without virions, a secondary structure model of a naked (protein-free) segment 7 vRNA has been determined using chemical mapping and thermodynamic energy minimization. The proposed structure model was validated using microarray mapping, RNase H cleavage and comparative sequence analysis...
September 30, 2016: Biochemical Journal
Zhong-Yu Liu, Xiao-Feng Li, Tao Jiang, Yong-Qiang Deng, Qing Ye, Hui Zhao, Jiu-Yang Yu, Cheng-Feng Qin
Viral replicase recruitment and long-range RNA interactions are essential for RNA virus replication, yet the mechanism of their interplay remains elusive. Flaviviruses include numerous important human pathogens, e.g., dengue virus (DENV) and Zika virus (ZIKV). Here, we revealed a highly conserved, conformation-tunable cis-acting element named 5'-UAR-flanking stem (UFS) in the flavivirus genomic 5' terminus. We demonstrated that the UFS was critical for efficient NS5 recruitment and viral RNA synthesis in different flaviviruses...
October 1, 2016: ELife
James Kirui, Arindam Mondal, Andrew Mehle
: The influenza A virus polymerase plays an essential role in the virus lifecycle, directing synthesis of viral mRNAs and genomes. It is a trimeric complex composed of subunits PA, PB1, and PB2 and associates with viral RNAs and nucleoprotein (NP) to form higher order ribonucleoprotein (RNP) complexes. The polymerase is regulated temporally over the course of infection to ensure coordinated expression of viral genes as well as replication of the viral genome. Various host factors and processes have been implicated in regulation of the IAV polymerase function, including post-translational modifications, however the mechanisms are not fully understood...
September 28, 2016: Journal of Virology
Aaron Coey, Kevin Larsen, Joseph D Puglisi, Elisabetta Viani Puglisi
Reverse transcription is a key process in the early steps of HIV infection. This process initiates within a specific complex formed by the 5' UTR of the HIV genomic RNA (vRNA) and a host primer tRNA(Lys) 3 Using nuclear magnetic resonance (NMR) spectroscopy and single-molecule fluorescence spectroscopy, we detect two distinct conformers adopted by the tRNA/vRNA initiation complex. We directly show that an interaction between the conserved 8-nucleotide viral RNA primer activation signal (PAS) and the primer tRNA occurs in one of these conformers...
September 9, 2016: RNA
Sumiho Nakatsu, Hiroshi Sagara, Yuko Sakai-Tagawa, Norio Sugaya, Takeshi Noda, Yoshihiro Kawaoka
UNLABELLED: The genomes of influenza A and B viruses comprise eight segmented, single-stranded, negative-sense viral RNAs (vRNAs). Although segmentation of the virus genome complicates the packaging of infectious progeny into virions, it provides an evolutionary benefit in that it allows viruses to exchange vRNAs with other strains. Influenza A viruses are believed to package their eight different vRNAs in a specific manner. However, several studies have shown that many viruses are noninfectious and fail to package at least one vRNA...
2016: MBio
Brad Gilbertson, Tian Zheng, Marie Gerber, Anne Printz-Schweigert, Chi Ong, Roland Marquet, Catherine Isel, Steven Rockman, Lorena Brown
The influenza A virus genome comprises eight negative-sense viral RNAs (vRNAs) that form individual ribonucleoprotein (RNP) complexes. In order to incorporate a complete set of each of these vRNAs, the virus uses a selective packaging mechanism that facilitates co-packaging of specific gene segments but whose molecular basis is still not fully understood. Recently, we used a competitive transfection model where plasmids encoding the A/Puerto Rico/8/34 (PR8) and A/Udorn/307/72 (Udorn) PB1 gene segments were competed to show that the Udorn PB1 gene segment is preferentially co-packaged into progeny virions with the Udorn NA gene segment...
2016: Viruses
Catherine Isel, Sandie Munier, Nadia Naffakh
The genome of influenza A viruses (IAV) consists of eight single-stranded negative sense viral RNAs (vRNAs) encapsidated into viral ribonucleoproteins (vRNPs). It is now well established that genome packaging (i.e., the incorporation of a set of eight distinct vRNPs into budding viral particles), follows a specific pathway guided by segment-specific cis-acting packaging signals on each vRNA. However, the precise nature and function of the packaging signals, and the mechanisms underlying the assembly of vRNPs into sub-bundles in the cytoplasm and their selective packaging at the viral budding site, remain largely unknown...
2016: Viruses
Elzbieta Lenartowicz, Aitor Nogales, Elzbieta Kierzek, Ryszard Kierzek, Luis Martínez-Sobrido, Douglas H Turner
Influenza A virus (IAV) affects 5%-10% of the world's population every year. Through genome changes, many IAV strains develop resistance to currently available anti-influenza therapeutics. Therefore, there is an urgent need to find new targets for therapeutics against this important human respiratory pathogen. In this study, 2'-O-methyl and locked nucleic acid antisense oligonucleotides (ASOs) were designed to target internal regions of influenza A/California/04/2009 (H1N1) genomic viral RNA segment 8 (vRNA8) based on a base-pairing model of vRNA8...
October 2016: Nucleic Acid Therapeutics
Claire Deleage, Stephen W Wietgrefe, Gregory Del Prete, David R Morcock, Xing Pei Hao, Michael Piatak, Julian Bess, Jodi L Anderson, Katherine E Perkey, Cavan Reilly, Joseph M McCune, Ashley T Haase, Jeffrey D Lifson, Timothy W Schacker, Jacob D Estes
A primary obstacle to an HIV-1 cure is long-lived viral reservoirs, which must be eliminated or greatly reduced. Cure strategies have largely focused on monitoring changes in T cell reservoirs in peripheral blood (PB), even though the lymphoid tissues (LT) are primary sites for viral persistence. To track and discriminate viral reservoirs within tissue compartments we developed a specific and sensitive next-generation in situ hybridization approach to detect vRNA, including vRNA+ cells and viral particles ("RNAscope"), vDNA+ cells ("DNAscope") and combined vRNA and vDNA with immunohistochemistry to detect and phenotype active and latently infected cells in the same tissue section...
2016: Pathogens & Immunity
Katherine E Hornak, Jean-Marc Lanchy, J Stephen Lodmell
The Bunyaviridae represents the largest family of segmented RNA viruses, which infect a staggering diversity of plants, animals, and insects. Within the family Bunyaviridae, the Phlebovirus genus includes several important human and animal pathogens, including Rift Valley fever virus (RVFV), severe fever with thrombocytopenia syndrome virus (SFTSV), Uukuniemi virus (UUKV), and the sandfly fever viruses. The phleboviruses have small tripartite RNA genomes that encode a repertoire of 5-7 proteins. These few proteins accomplish the daunting task of recognizing and specifically packaging a tri-segment complement of viral genomic RNA in the midst of an abundance of host components...
2016: Viruses
Gian Luca Autorino, Claudia Eleni, Giuseppe Manna, Raffaele Frontoso, Roberto Nardini, Cristiano Cocumelli, Francesca Rosone, Andrea Caprioli, Lavinia Alfieri, Maria Teresa Scicluna
Information on equine infectious anaemia (EIA) in mules, including those with an equivocal reaction in agar gel immunodiffusion test (AGIDT), is scarce. For this, a study was conducted to evaluate the clinical, viral loads and pathological findings of two groups of naturally infected asymptomatic mules, respectively with a negative/equivocal and positive AGIDT reactivity, which were subjected to pharmacological immune suppression (IS). A non-infected control was included in the study that remained negative during the observation period...
June 30, 2016: Veterinary Microbiology
Seong-Su Yuk, Dong-Hun Lee, Jae-Keun Park, Erdene-Ochir Tseren-Ochir, Jung-Hoon Kwon, Jin-Yong Noh, Joong-Bok Lee, Seung-Yong Park, In-Soo Choi, Chang-Seon Song
BACKGROUND: Interferon gamma (IFN-γ), an immunoregulatory cytokine, is known to control many microbial infections. In a previous study, chicken interferon gamma (chIFN-γ) was found to be up-regulated following avian influenza virus (AIV) infection in specific pathogen-free chickens. We aimed to investigate whether the pre-immune state induced by chIFN-γ could generate an antiviral response against influenza virus. METHODS: We generated a chIFN-γ-expressing plasmid and transfected it into chicken embryo fibroblasts (CEFs) and then infected the cells with human origin H1N1 or avian origin H9N2 influenza viruses...
2016: Virology Journal
Joshua Kelly, Alexander Y Grosberg, Robijn Bruinsma
We develop a Flory mean-field theory for viral RNA (vRNA) molecules that extends the current RNA folding algorithms to include interactions between different sections of the secondary structure. The theory is applied to sequence-selective vRNA encapsidation. The dependence on sequence enters through a single parameter: the largest eigenvalue of the Kramers matrix of the branched polymer obtained by coarse graining the secondary structure. Differences between the work of encapsidation of vRNA molecules and of randomized isomers are found to be in the range of 20 kBT, more than sufficient to provide a strong bias in favor of vRNA encapsidation...
July 7, 2016: Journal of Physical Chemistry. B
Christopher Swale, Alexandre Monod, Laura Tengo, Alice Labaronne, Frédéric Garzoni, Jean-Marie Bourhis, Stephen Cusack, Guy Schoehn, Imre Berger, Rob W H Ruigrok, Thibaut Crépin
The genome of influenza A virus (IAV) comprises eight RNA segments (vRNA) which are transcribed and replicated by the heterotrimeric IAV RNA-dependent RNA-polymerase (RdRp). RdRp consists of three subunits (PA, PB1 and PB2) and binds both the highly conserved 3'- and 5'-ends of the vRNA segment. The IAV RdRp is an important antiviral target, but its structural mechanism has remained largely elusive to date. By applying a polyprotein strategy, we produced RdRp complexes and define a minimal human IAV RdRp core complex...
2016: Scientific Reports
Ling Li, Huining Pang, Rui Wu, Yanwen Zhang, Yiluo Tan, Zishu Pan
We describe an alternative reverse genetics system for generating classical swine fever virus (CSFV) based on swine RNA polymerase I promoter (pSPI)-mediated vRNA transcription. The recombinant plasmid pSPTI/SM harboring a full-length CSFV Shimen strain cDNA, flanked by a swine RNA polymerase I (pol I) promoter sequence at the 5' end and a murine pol I terminator sequence at the 3' end, was constructed. When the plasmid pSPTI/SM was introduced into PK-15 cells by transfection, an infectious CSFV with termini identical to those of the parental virus was generated directly...
July 2016: Archives of Virology
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