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Flavivirus NS2A

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https://www.readbyqxmd.com/read/28919920/virulence-determinants-of-west-nile-virus-how-can-these-be-used-for-vaccine-design
#1
REVIEW
Jaclyn A Kaiser, Tian Wang, Alan Dt Barrett
West Nile virus (WNV), a neurotropic mosquito-borne flavivirus, has become endemic in the USA and parts of Europe since 1999. There is no licensed WNV vaccine for humans. Considering the robust immunity from immunization with live, attenuated vaccines, a live WNV vaccine is an ideal platform for disease control. Animal and mosquito studies have identified a number of candidate attenuating mutations, including the structural proteins premembrane/membrane and envelope, and the nonstructural proteins NS1, NS2A, NS3, NS4A, NS4B and NS5, and the 3' UTR...
May 2017: Future Virology
https://www.readbyqxmd.com/read/28441781/dengue-virus-non-structural-protein-5
#2
REVIEW
Abbas El Sahili, Julien Lescar
The World Health Organization estimates that the yearly number of dengue cases averages 390 million. This mosquito-borne virus disease is endemic in over 100 countries and will probably continue spreading, given the observed trend in global warming. So far, there is no antiviral drug available against dengue, but a vaccine has been recently marketed. Dengue virus also serves as a prototype for the study of other pathogenic flaviviruses that are emerging, like West Nile virus and Zika virus. Upon viral entry into the host cell and fusion of the viral lipid membrane with the endosomal membrane, the viral RNA is released and expressed as a polyprotein, that is then matured into three structural and seven non-structural (NS) proteins...
April 24, 2017: Viruses
https://www.readbyqxmd.com/read/28411164/high-levels-of-local-inter-and-intra-host-genetic-variation-of-west-nile-virus-and-evidence-of-fine-scale-evolutionary-pressures
#3
Dylan J Ehrbar, Kiet A Ngo, Scott R Campbell, Laura D Kramer, Alexander T Ciota
West Nile virus (WNV; Flaviviridae, Flavivirus) has been endemic in New York State (NYS) since its 1999 introduction, yet prevalence in Culex mosquitoes varies substantially over small spatial and temporal scales. It is unclear if viral genetics plays a role in this variability, as genetic and phenotypic characterization on local scales has generally been lacking. In addition, intrahost diversity of circulating strains have not been fully characterized despite the documented role of minority variants in viral fitness and virulence...
April 12, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28388487/characterization-of-virus-specific-vesicles-assembled-by-west-nile-virus-non-structural-proteins
#4
Li Yu, Kazuyo Takeda, Yamei Gao
Flavivirus genome encodes seven non-structural proteins (NSPs) and these NSPs are believed to be involved in their genomic RNA replication, of which the mechanism is unclear. We find that West Nile virus (WNV) NSPs were capable of self-assembling membranous vesicles in cells, which are composed of the host endoplasmic reticulum membrane integrated with viral NS1 and NS4A, and possibly NS2A. The vesicles can further organize into replication complex (RC)-associated vesicles which combine both the vesicle and predicted RC components...
June 2017: Virology
https://www.readbyqxmd.com/read/28381578/mutagenesis-of-dengue-virus-protein-ns2a-revealed-a-novel-domain-responsible-for-virus-induced-cytopathic-effect-and-interactions-between-ns2a-and-ns2b-transmembrane-segments
#5
Ren-Huang Wu, Ming-Han Tsai, Kuen-Nan Tsai, Jia Ni Tian, Jian-Sung Wu, Su-Ying Wu, Jyh-Haur Chern, Chun-Hong Chen, Andrew Yueh
The NS2A protein of dengue virus (DENV) has eight predicted transmembrane segments (pTMS1 to -8) and participates in RNA replication, virion assembly, and host antiviral response. However, the roles of specific amino acid residues within the pTMS regions of NS2A during the viral life cycle are not clear. Here, we explore the function of DENV NS2A by introducing a series of alanine substitutions into the N-terminal half (pTMS1 to -4) of the protein in the context of a DENV infectious clone or subgenomic replicon...
June 15, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28261172/the-complement-system-in-flavivirus-infections
#6
Jonas N Conde, Emiliana M Silva, Angela S Barbosa, Ronaldo Mohana-Borges
The incidence of flavivirus infections has increased dramatically in recent decades in tropical and sub-tropical climates worldwide, affecting hundreds of millions of people each year. The Flaviviridae family includes dengue, West Nile, Zika, Japanese encephalitis, and yellow fever viruses that are typically transmitted by mosquitoes or ticks, and cause a wide range of symptoms, such as fever, shock, meningitis, paralysis, birth defects, and death. The flavivirus genome is composed of a single positive-sense RNA molecule encoding a single viral polyprotein...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28196656/a-cdna-clone-launched-platform-for-high-yield-production-of-inactivated-zika-vaccine
#7
Yujiao Yang, Chao Shan, Jing Zou, Antonio E Muruato, Diniz Nunes Bruno, Barbosa de Almeida Medeiros Daniele, Pedro F C Vasconcelos, Shannan L Rossi, Scott C Weaver, Xuping Xie, Pei-Yong Shi
A purified inactivated vaccine (PIV) using the Zika virus (ZIKV) Puerto Rico strain PRVABC59 showed efficacy in monkeys, and is currently in a phase I clinical trial. High-yield manufacture of this PIV is essential for its development and vaccine access. Here we report an infectious cDNA clone-launched platform to maximize its yield. A single NS1 protein substitution (K265E) was identified to increase ZIKV replication on Vero cells (a cell line approved for vaccine production) for both Cambodian FSS13025 and Puerto Rico PRVABC59 strains...
March 2017: EBioMedicine
https://www.readbyqxmd.com/read/27746901/illustrating-and-homology-modeling-the-proteins-of-the-zika-virus
#8
Sean Ekins, John Liebler, Bruno J Neves, Warren G Lewis, Megan Coffee, Rachelle Bienstock, Christopher Southan, Carolina H Andrade
The Zika virus (ZIKV) is a flavivirus of the family Flaviviridae, which is similar to dengue virus, yellow fever and West Nile virus. Recent outbreaks in South America, Latin America, the Caribbean and in particular Brazil have led to concern for the spread of the disease and potential to cause Guillain-Barré syndrome and microcephaly. Although ZIKV has been known of for over 60 years there is very little in the way of knowledge of the virus with few publications and no crystal structures. No antivirals have been tested against it either in vitro or in vivo...
2016: F1000Research
https://www.readbyqxmd.com/read/27665292/a-simple-method-for-developing-an-infectious-cdna-clone-of-japanese-encephalitis-virus
#9
Hao Zheng, Xuchen Zheng, Wu Tong, Fei Liu, Chao Liang, Tao Wang, Fei Gao, Liwei Li, Tongling Shan, Guoxin Li, Guangzhi Tong
Flavivirus cDNA clones frequently demonstrate genetic instability in transformed bacteria, which hampers the construction and manipulation of cDNAs for infectious flaviviruses. In this study, we developed a stable, full-length cDNA clone, pJEHEN, of a GI JEV strain HEN0701 using a medium-copy-number pBR322 vector and propagating cDNA clones at room temperature. The virus vJEHEN recovered from the infectious clone was indistinguishable from the parent virus HEN0701 with respect to plaque morphology, growth kinetics, and virulence characteristics...
February 2017: Virus Genes
https://www.readbyqxmd.com/read/27296393/predicting-zika-virus-structural-biology-challenges-and-opportunities-for-intervention
#10
Bryan D Cox, Richard A Stanton, Raymond F Schinazi
BACKGROUND: Zika virus is an emerging crisis as infection is implicated in severe neurological disorders-Guillain-Barré syndrome and fetal microcephaly. There are currently no treatment options available for Zika virus infection. This virus is part of the flavivirus genus and closely related to Dengue Fever Virus, West Nile Virus, and Japanese Encephalitis Virus. Like other flaviviruses, the Zika virus genome encodes three structural proteins (capsid, precursor membrane, and envelope) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5)...
August 2015: Antiviral Chemistry & Chemotherapy
https://www.readbyqxmd.com/read/27169727/population-genomics-of-dengue-virus-serotype-4-insights-into-genetic-structure-and-evolution
#11
Vaishali P Waman, Sunitha Manjari Kasibhatla, Mohan M Kale, Urmila Kulkarni-Kale
The spread of dengue disease has become a global public health concern. Dengue is caused by dengue virus, which is a mosquito-borne arbovirus of the genus Flavivirus, family Flaviviridae. There are four dengue virus serotypes (1-4), each of which is known to trigger mild to severe disease. Dengue virus serotype 4 (DENV-4) has four genotypes and is increasingly being reported to be re-emerging in various parts of the world. Therefore, the population structure and factors shaping the evolution of DENV-4 strains across the world were studied using genome-based population genetic, phylogenetic and selection pressure analysis methods...
August 2016: Archives of Virology
https://www.readbyqxmd.com/read/27053551/transmembrane-domains-of-ns2b-contribute-to-both-viral-rna-replication-and-particle-formation-in-japanese-encephalitis-virus
#12
Xiao-Dan Li, Cheng-Lin Deng, Han-Qing Ye, Hong-Lei Zhang, Qiu-Yan Zhang, Dong-Dong Chen, Pan-Tao Zhang, Pei-Yong Shi, Zhi-Ming Yuan, Bo Zhang
UNLABELLED: Flavivirus nonstructural protein 2B (NS2B) is a transmembrane protein that functions as a cofactor for viral NS3 protease. The cytoplasmic region (amino acids 51 to 95) alone of NS2B is sufficient for NS3 protease activity, whereas the role of transmembrane domains (TMDs) remains obscure. Here, we demonstrate for the first time that flavivirus NS2B plays a critical role in virion assembly. Using Japanese encephalitis virus (JEV) as a model, we performed a systematic mutagenesis at the flavivirus conserved residues within the TMDs of NS2B...
June 15, 2016: Journal of Virology
https://www.readbyqxmd.com/read/26377679/proteolytic-cleavage-analysis-at-the-murray-valley-encephalitis-virus-ns1-2a-junction
#13
COMPARATIVE STUDY
Siti Nor Khadijah Addis, Eva Lee, Jayaram Bettadapura, Mario Lobigs
BACKGROUND: Our understanding of the proteolytic processing events at the NS1-2A junction in the flavivirus polyprotein has not markedly progressed since the early work conducted on dengue virus (DENV). This work identified an octapeptide sequence located immediately upstream of the cleavage site thought to be important in substrate recognition by an as yet unknown, endoplasmic reticulum-resident host protease. Of the eight amino acid recognition sequence, the highly conserved residues at positions P1, P3, P5, P7 and P8 (with respect to N-terminus of NS2A) are particularly sensitive to amino acid substitutions in terms of DENV NS1-NS2A cleavage efficiency; however, the role of the octapeptide in efficient NS1 and NS2A production of other flaviviruses has not been experimentally addressed...
2015: Virology Journal
https://www.readbyqxmd.com/read/25915765/profiling-of-viral-proteins-expressed-from-the-genomic-rna-of-japanese-encephalitis-virus-using-a-panel-of-15-region-specific-polyclonal-rabbit-antisera-implications-for-viral-gene-expression
#14
Jin-Kyoung Kim, Jeong-Min Kim, Byung-Hak Song, Sang-Im Yun, Gil-Nam Yun, Sung-June Byun, Young-Min Lee
Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is closely related to West Nile (WN), yellow fever (YF), and dengue (DEN) viruses. Its plus-strand genomic RNA carries a single open reading frame encoding a polyprotein that is cleaved into three structural (C, prM/M, and E) and at least seven nonstructural (NS1/NS1', NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins, based on previous work with WNV, YFV, and DENV. Here, we aimed to profile experimentally all the viral proteins found in JEV-infected cells...
2015: PloS One
https://www.readbyqxmd.com/read/25694595/a-basic-cluster-in-the-n-terminus-of-yellow-fever-virus-ns2a-contributes-to-infectious-particle-production
#15
Stephanie Voßmann, Janett Wieseler, Romy Kerber, Beate Mareike Kümmerer
UNLABELLED: The flavivirus NS2A protein is involved in the assembly of infectious particles. To further understand its role in this process, a charged-to-alanine scanning analysis was performed on NS2A encoded by an infectious cDNA clone of yellow fever virus (YFV). Fifteen mutants containing single, double, or triple charged-to-alanine changes were tested. Five of them did not produce infectious particles, whereas efficient RNA replication was detectable for two of the five NS2A mutants (R22A-K23A-R24A and R99A-E100A-R101A mutants)...
May 2015: Journal of Virology
https://www.readbyqxmd.com/read/25653435/scanning-mutagenesis-studies-reveal-a-potential-intramolecular-interaction-within-the-c-terminal-half-of-dengue-virus-ns2a-involved-in-viral-rna-replication-and-virus-assembly-and-secretion
#16
Ren-Huang Wu, Ming-Han Tsai, Day-Yu Chao, Andrew Yueh
UNLABELLED: The NS2A protein of dengue virus (DENV) has eight predicted transmembrane segments (pTMSs; pTMS1 to pTMS8). NS2A has been shown to participate in RNA replication, virion assembly, and the host antiviral response. However, the role of the amino acid residues within the pTMS regions of NS2A during the virus life cycle is poorly understood. In the study described here, we explored the function of DENV NS2A by introducing a series of double or triple alanine substitutions into the C-terminal half (pTMS4 to pTMS8) of NS2A in the context of a DENV infectious clone or subgenomic replicon...
April 2015: Journal of Virology
https://www.readbyqxmd.com/read/25568208/characterization-of-dengue-virus-ns4a-and-ns4b-protein-interaction
#17
Jing Zou, Xuping Xie, Qing-Yin Wang, Hongping Dong, Michelle Yueqi Lee, Congbao Kang, Zhiming Yuan, Pei-Yong Shi
UNLABELLED: Flavivirus replication is mediated by a membrane-associated replication complex where viral membrane proteins NS2A, NS2B, NS4A, and NS4B serve as the scaffold for the replication complex formation. Here, we used dengue virus serotype 2 (DENV-2) as a model to characterize viral NS4A-NS4B interaction. NS4A interacts with NS4B in virus-infected cells and in cells transiently expressing NS4A and NS4B in the absence of other viral proteins. Recombinant NS4A and NS4B proteins directly bind to each other with an estimated Kd (dissociation constant) of 50 nM...
April 2015: Journal of Virology
https://www.readbyqxmd.com/read/25392211/two-distinct-sets-of-ns2a-molecules-are-responsible-for-dengue-virus-rna-synthesis-and-virion-assembly
#18
Xuping Xie, Jing Zou, Chunya Puttikhunt, Zhiming Yuan, Pei-Yong Shi
UNLABELLED: Flavivirus nonstructural protein 2A (NS2A) plays important roles in both viral RNA synthesis and virion assembly. The molecular details of how the NS2A protein modulates the two distinct events have not been defined. To address this question, we have performed a systematic mutagenesis of NS2A using dengue virus (DENV) serotype 2 (DENV-2) as a model. We identified two sets of NS2A mutations with distinct defects during a viral infection cycle. One set of NS2A mutations (D125A and G200A) selectively abolished viral RNA synthesis...
January 15, 2015: Journal of Virology
https://www.readbyqxmd.com/read/25375107/programmed-ribosomal-frameshift-alters-expression-of-west-nile-virus-genes-and-facilitates-virus-replication-in-birds-and-mosquitoes
#19
Ezequiel Balmori Melian, Sonja Hall-Mendelin, Fangyao Du, Nick Owens, Angela M Bosco-Lauth, Tomoko Nagasaki, Stephen Rudd, Aaron C Brault, Richard A Bowen, Roy A Hall, Andrew F van den Hurk, Alexander A Khromykh
West Nile virus (WNV) is a human pathogen of significant medical importance with close to 40,000 cases of encephalitis and more than 1,600 deaths reported in the US alone since its first emergence in New York in 1999. Previous studies identified a motif in the beginning of non-structural gene NS2A of encephalitic flaviviruses including WNV which induces programmed -1 ribosomal frameshift (PRF) resulting in production of an additional NS protein NS1'. We have previously demonstrated that mutant WNV with abolished PRF was attenuated in mice...
November 2014: PLoS Pathogens
https://www.readbyqxmd.com/read/24696348/construction-of-plasmid-bacterial-expression-purification-and-assay-of-dengue-virus-type-2-ns5-methyltransferase
#20
Siwaporn Boonyasuppayakorn, Radhakrishnan Padmanabhan
Dengue virus (DENV), a member of mosquito-borne flavivirus, causes self-limiting dengue fever as well as life-threatening dengue hemorrhagic fever and dengue shock syndrome. Its positive sense RNA genome has a cap at the 5'-end and no poly(A) tail at the 3'-end. The viral RNA encodes a single polyprotein, C-prM-E-NS1-NS2A-NS2B-NS3-NS4A-NS4B-NS5. The polyprotein is processed into 3 structural proteins (C, prM, and E) and 7 nonstructural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5). NS3 and NS5 are multifunctional enzymes performing various tasks in viral life cycle...
2014: Methods in Molecular Biology
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