scholarly journals Synthesis and Localization of Japanese Encephalitis Virus RNAs in the Infected Cells

1990 ◽  
Vol 34 (10) ◽  
pp. 849-857 ◽  
Author(s):  
Tsutomu Takegami ◽  
Susumu Hotta
Virology ◽  
1973 ◽  
Vol 56 (1) ◽  
pp. 95-109 ◽  
Author(s):  
Daniel Shapiro ◽  
Kathleen A. Kos ◽  
Philip K. Russell

1999 ◽  
Vol 73 (8) ◽  
pp. 6257-6264 ◽  
Author(s):  
Yu-Shiu Chang ◽  
Ching-Len Liao ◽  
Chang-Huei Tsao ◽  
Mei-Chieh Chen ◽  
Chiu-I Liu ◽  
...  

ABSTRACT Infection with Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, may cause acute encephalitis in humans and induce severe cytopathic effects in various types of cultured cells. We observed that JEV replication rendered infected baby hamster kidney (BHK-21) cells sensitive to the translational inhibitor hygromycin B or α-sarcine, to which mock-infected cells were insensitive. However, little is known about whether any JEV nonstructural (NS) proteins contribute to virus-induced changes in membrane permeability. Using an inducibleEscherichia coli system, we investigated which parts of JEV NS1 to NS4 are capable of modifying membrane penetrability. We found that overexpression of NS2B-NS3, the JEV protease, permeabilized bacterial cells to hygromycin B whereas NS1 expression failed to do so. When expressed separately, NS2B alone, but not NS3, was sufficient to alter bacterial membrane permeability. Similarly, expression of NS4A or NS4B also rendered bacteria susceptible to hygromycin B inhibition. Examination of the effect of NS1 to NS4 expression on bacterial growth rate showed that NS2B exhibited the greatest inhibitory capability, followed by a modest repression from NS2A and NS4A, whereas NS1, NS3, and NS4B had only trivial influence with respect to the vector control. Furthermore, when cotransfected with a reporter gene luciferase or β-galactosidase, transient expression of NS2A, NS2B, and NS4B markedly reduced the reporter activity in BHK-21 cells. Together, our results suggest that upon JEV infection, these four small hydrophobic NS proteins have various modification effects on host cell membrane permeability, thereby contributing in part to virus-induced cytopathic effects in infected cells.


Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1246
Author(s):  
Chit Care ◽  
Wannapa Sornjai ◽  
Janejira Jaratsittisin ◽  
Atitaya Hitakarun ◽  
Nitwara Wikan ◽  
...  

Kaempferol, a plant-derived flavonoid, has been reported to have activity against Japanese encephalitis virus (JEV) in BHK-21 cells. To determine the broader utility of this compound, we initially evaluated the activity of kaempferol against JEV and dengue virus (DENV) in HEK293T/17 cells. Results showed no significant antiviral activity against either virus. We subsequently investigated the activity of kaempferol against both JEV and DENV in BHK-21 cells. Results showed a significant inhibition of JEV infection but, surprisingly, a significant enhancement of DENV infection. The effect of kaempferol on both host protein expression and transcription was investigated and both transcriptional and translational inhibitory effects were observed, although a more marked effect was observed on host cell protein expression. Markedly, while GRP78 was increased in DENV infected cells treated with kaempferol, it was not increased in JEV infected cells treated with kaempferol. These results show that cellular alteration induced by one compound can have opposite effects on viruses from the same family, suggesting the presence of distinct replication strategies for these two viruses.


2004 ◽  
Vol 78 (17) ◽  
pp. 9285-9294 ◽  
Author(s):  
Ren-Jye Lin ◽  
Ching-Len Liao ◽  
Elong Lin ◽  
Yi-Ling Lin

ABSTRACT The induction of alpha/beta interferon (IFN-α/β) is a powerful host defense mechanism against viral infection, and many viruses have evolved strategies to overcome the antiviral effects of IFN. In this study, we found that IFN-α had only some degree of antiviral activity against Japanese encephalitis virus (JEV) infection, in contrast to another flavivirus, dengue virus serotype 2, which was highly sensitive to IFN-α in the cultured cell system. JEV infection appeared to render cells resistant to IFN-α since the IFN-α-induced luciferase reporter activity driven by the IFN-stimulated response element (ISRE) was gradually reduced as the JEV infection progressed. Since the biological activities of IFNs are triggered by the Janus kinase (Jak) signal transducer and activation of transcription (Stat) signaling cascade, we then studied the activation of Jak-Stat pathway in the virus-infected cells. The IFN-α-stimulated tyrosine phosphorylation of Stat1, Stat2, and Stat3 was suppressed by JEV in a virus replication and de novo protein synthesis-dependent manner. Furthermore, JEV infection blocked the tyrosine phosphorylation of IFN receptor-associated Jak kinase, Tyk2, without affecting the expression of IFN-α/β receptor on the cell surface. Consequently, expression of several IFN-stimulated genes in response to IFN-α stimulation was also reduced in the JEV-infected cells. Overall, our findings suggest that JEV counteracts the effect of IFN-α/β by blocking Tyk2 activation, thereby resulting in inhibition of Jak-Stat signaling pathway.


2015 ◽  
Vol 90 (3) ◽  
pp. 1178-1189 ◽  
Author(s):  
Li-Chen Yen ◽  
Jia-Teh Liao ◽  
Hwei-Jen Lee ◽  
Wei-Yuan Chou ◽  
Chun-Wei Chen ◽  
...  

ABSTRACTNS1 is the only nonstructural protein that enters the lumen of the endoplasmic reticulum (ER), where NS1 is glycosylated, forms a dimer, and is subsequently secreted during flavivirus replication as dimers or hexamers, which appear to be highly immunogenic to the infected host, as protective immunity can be elicited against homologous flavivirus infections. Here, by using atrans-complementation assay, we identified the C-terminal end of NS1 derived from Japanese encephalitis virus (JEV), which was more flexible than other regions in terms of housing foreign epitopes without a significant impact on virus replication. This mapped flexible region is located in the conserved tip of the core β-ladder domain of the multimeric NS1 structure and is also known to contain certain linear epitopes, readily triggering specific antibody responses from the host. Despite becoming attenuated, recombinant JEV with insertion of a neutralizing epitope derived from enterovirus 71 (EV71) into the C-terminal end of NS1 not only could be normally released from infected cells, but also induced dual protective immunity for the host to counteract lethal challenge with either JEV or EV71 in neonatal mice. These results indicated that the secreted multimeric NS1 of flaviviruses may serve as a natural protein carrier to render epitopes of interest more immunogenic in the C terminus of the core β-ladder domain.IMPORTANCEThe positive-sense RNA genomes of mosquito-borne flaviviruses appear to be flexible in terms of accommodating extra insertions of short heterologous antigens into their virus genes. Here, we illustrate that the newly identified C terminus of the core β-ladder domain in NS1 could be readily inserted into entities such as EV71 epitopes, and the resulting NS1-epitope fusion proteins appeared to maintain normal virus replication, secretion ability, and multimeric formation from infected cells. Nonetheless, such an insertion attenuated the recombinant JEV in mice, despite having retained the brain replication ability observed in wild-type JEV. Mother dams immunized with recombinant JEV expressing EV71 epitope-NS1 fused proteins elicited neutralizing antibodies that protected the newborn mice against lethal EV71 challenge. Together, our results implied a potential application of JEV NS1 as a viral carrier protein to express a heterologous epitope to stimulate dual/multiple protective immunity concurrently against several pathogens.


2021 ◽  
Vol 22 (8) ◽  
pp. 4218
Author(s):  
Chih-Wei Huang ◽  
Kuen-Nan Tsai ◽  
Yi-Shiuan Chen ◽  
Ruey-Yi Chang

MicroRNAs (miRNAs) play versatile roles in multiple biological processes. However, little is known about miRNA’s involvement in flavivirus persistent infection. Here, we used an miRNA array analysis of Japanese encephalitis virus (JEV)-infected cells to search for persistent infection-associated miRNAs in comparison to acute infection. Among all differentially expressed miRNAs, the miR-125b-5p is the most significantly increased one. The high level of miR-125b-5p in persistently JEV-infected cells was confirmed by Northern analysis and real-time quantitative polymerase chain reaction. As soon as the cells established a persistent infection, a significantly high expression of miR-125b-5p was readily observed. Transfecting excess quantities of a miR-125b-5p mimic into acutely infected cells reduced genome replication and virus titers. Host targets of miR125b-5p were analyzed by target prediction algorithms, and six candidates were confirmed by a dual-luciferase reporter assay. These genes were upregulated in the acutely infected cells and sharply declined in the persistently infected cells. The transfection of the miR125b-5p mimic reduced the expression levels of Stat3, Map2k7, and Triap1. Our studies indicated that miR-125b-5p targets both viral and host sequences, suggesting its role in coordinating viral replication and host antiviral responses. This is the first report to characterize the potential roles of miR-125b-5p in persistent JEV infections.


2005 ◽  
Vol 86 (8) ◽  
pp. 2209-2220 ◽  
Author(s):  
Zijiang Zhao ◽  
Tomoko Date ◽  
Yuhua Li ◽  
Takanobu Kato ◽  
Michiko Miyamoto ◽  
...  

A stable plasmid DNA, pMWJEAT, was constructed by using full-length Japanese encephalitis virus (JEV) cDNA isolated from the wild-type strain JEV AT31. Recombinant JEV was obtained by synthetic RNA transfection into Vero cells and designated rAT virus. JEV rAT exhibited similar large-plaque morphology and antigenicity to the parental AT31 strain. Mutant clone pMWJEAT-E138K, containing a single Glu-to-Lys mutation at aa 138 of the envelope (E) protein, was also constructed to analyse the mechanisms of viral attenuation arising from this mutation. Recombinant JEV rAT-E138K was also recovered and displayed a smaller-plaque morphology and lower neurovirulence and neuroinvasiveness than either AT31 virus or rAT virus. JEV rAT-E138K exhibited greater plaque formation than rAT virus in virus–cell interactions under acidic conditions. Heparin or heparinase III treatment inhibited binding to Vero cells more efficiently for JEV rAT-E138K than for rAT virus. Inhibition of virus–cell interactions by using wheatgerm agglutinin was more effective for JEV rAT than for rAT-E138K on Vero cells. About 20 % of macropinoendocytosis of JEV rAT for Vero cells was inhibited by cytochalasin D treatment, but no such inhibition occurred for rAT-E138K virus. Furthermore, JEV rAT was predominantly secreted from infected cells, whereas rAT-E138K was more likely to be retained in infected cells. This study demonstrates clearly that a single Glu-to-Lys mutation at aa 138 of the envelope protein affects multiple steps of the viral life cycle. These multiple changes may induce substantial attenuation of JEV.


Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 212
Author(s):  
Pakieli H. Kaufusi ◽  
Alanna C. Tseng ◽  
James F. Kelley ◽  
Vivek R. Nerurkar

Studies investigating West Nile virus (WNV) NS4B protein function are hindered by the lack of an antibody recognizing WNV NS4B protein. Few laboratories have produced WNV NS4B antibodies, and none have been shown to work consistently. In this report, we describe a NS4B antibody against Japanese encephalitis virus (JEV) NS4B protein that cross-reacts with the NS4B protein of WNV but not of dengue virus (DENV). This JEV NS4B antibody not only recognizes WNV NS4B in infected cells, but also recognizes the NS4B protein expressed using transfection. It is evident from this data that the JEV NS4B antibody is specific to NS4B of WNV but not to NS4B of the four DENV serotypes. The specificity of this antibody may be due to the notable differences that exist between the amino acid sequence identity and antigenic relationships within the NS4B protein of the WNV, DENV, and JEV.


2008 ◽  
Vol 82 (21) ◽  
pp. 10455-10464 ◽  
Author(s):  
Yi-Lin Chan ◽  
Tsung-Hsien Chang ◽  
Ching-Len Liao ◽  
Yi-Ling Lin

ABSTRACT Viperin is identified as an antiviral protein induced by interferon (IFN), viral infections, and pathogen-associated molecules. In this study, we found that viperin is highly induced at the RNA level by Japanese encephalitis virus (JEV) and Sindbis virus (SIN) and that viperin protein is degraded in JEV-infected cells through a proteasome-dependent mechanism. Promoter analysis revealed that SIN induces viperin expression in an IFN-dependent manner but that JEV by itself activates the viperin promoter through IFN regulatory factor-3 and AP-1. The overexpression of viperin significantly decreased the production of SIN, but not of JEV, whereas the proteasome inhibitor MG132 sustained the protein level and antiviral effect of viperin in JEV-infected cells. Knockdown of viperin expression by RNA interference also enhanced the replication of SIN, but not that of JEV. Our results suggest that even though viperin gene expression is highly induced by JEV, it is negatively regulated at the protein level to counteract its antiviral effect. In contrast, SIN induces viperin through the action of IFN, and viperin exhibits potent antiviral activity against SIN.


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