The A66G back mutation in NS2A of JEV SA 14 -14-2 strain contributes to production of NS1′ protein and the secreted NS1′ can be used for diagnostic biomarker for virulent virus infection

Wang, Jingman; Li, Xinfeng; Gu, Jinyan; Fan, Yu Lei; Zhao, Peng; Cao, Ruibing; Pu-yan, Chen

doi:10.1016/j.meegid.2015.09.013

Cited by 13 publications

(13 citation statements)

References 39 publications

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“… 10–14 In our previous studies, we observed that spleen cells that were immunized with SA14-14-2 effectively protected mice from virus infection, even though mice had a low level of neutralizing antibodies (<10). 15 Similar findings were made with guinea pigs that had low levels of neutralizing antibodies and yet survived challenge from virulent strains. 16 It has also been reported that immunization with SA14-14-2 NS1 protein induced a strong protective response in mice.…”

Section: Discussionsupporting

confidence: 60%

The molecular determinants governing the immunogenicity of Japanese encephalitis live attenuated vaccines

Yin

Liu

et al. 2017

Sig Transduct Target Ther

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In the course of isolating the attenuated Japanese encephalitis vaccine SA14-14-2, two attenuated strains SA14-9-7 and SA14-5-3 were also obtained that elicited low antibody responses in humans (<10% and 62%, respectively) and exerted much weaker immune protection in animal challenge experiments. However, the reason for these differences remains unknown. In order to understand why SA14-14-2 is superior to SA14-9-7 and SA14-5-3, we employed a reverse genetics method to identify the key mutations in the virus genome that determine the immunogenicity of live attenuated Japanese encephalitis viruses. We first sequenced the full genomic sequences of SA14-9-7 and SA14-5-3 and found mutations that changed four amino-acid base pairs when compared to the envelope gene of SA14-14-2. We mutated the genome of SA14-14-2 to generate these mutations both singly (E-177, E-264, E-279 and E-315) and in combination (E-177/264, E-279/315 and E-177/264/279/315) and tested these mutants along with parental strains SA14-14-2, SA14-9-7 and SA14-5-3 for their immunogenicity in vivo. When mice were immunized with SA14-9-7 and SA14-5-3, lower levels of neutralizing antibodies were generated compared with the immune response to SA14-14-2. Furthermore, SA14-5-3 was more immunogenic than SA14-9-7, which replicated the results previously seen in humans. Point mutations E-177, E-264, E-279 and E-315 diminished the immunogenicity of SA14-14-2 with E-264 and E-315, contributing the most to this phenotype. The mutant rJEV (E-177/E-264/E-279/E-315) containing all four point mutations exhibited the lowest immunogenicity with a seroconversion rate of 0 at an inoculation dose of 103 PFU (plaque-forming unit). We have identified the key amino acids in the envelope protein that account for the superior immunogenicity of SA14-14-2.

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Section: Discussionsupporting

confidence: 60%

The molecular determinants governing the immunogenicity of Japanese encephalitis live attenuated vaccines

Yin

Liu

et al. 2017

Sig Transduct Target Ther

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“…NS1 0 , a 52 amino acid C-terminal extension of NS1, was first detected in JEV-infected cells generated by a -1 programmed ribosomal frameshift (PRF) via a slippery heptanucleotide (YCCUUUU) and potential pseudoknot nearby (Blitvich et al 1999;Firth and Atkins 2009). It has been reported that NS1 0 in West Nile virus (WNV) and JEV play important roles in neuroinvasiveness, but the mechanism has not been clarified (Melian et al 2010;Wang et al 2015;Ye et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Japanese Encephalitis Virus NS1′ Protein Antagonizes Interferon Beta Production

Zhou

Fan

et al. 2018

Virol. Sin.

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Japanese encephalitis virus (JEV) is a mosquito-borne virus and the major cause of viral encephalitis in Asia. NS1 0 , a 52-amino acid C-terminal extension of NS1, is generated with a-1 programmed ribosomal frameshift and is only present in members of the Japanese encephalitis serogroup of flaviviruses. Previous studies demonstrated that NS1 0 plays a vital role in virulence, but the mechanism is unclear. In this study, an NS1 0 defected (rG66A) virus was generated. We found that rG66A virus was less virulent than its parent virus (pSA14) in wild-type mice. However, similar mortality caused by the two viruses was observed in an IFNAR knockout mouse model. Moreover, we found that rG66A virus induced a greater type I interferon (IFN) response than that by pSA14, and JEV NS1 0 significantly inhibited the production of IFN-b and IFN-stimulated genes. Taken together, our results reveal that NS1 0 plays a vital role in blocking type I IFN production to help JEV evade antiviral immunity and benefit viral replication. Keywords Japanese encephalitis virus (JEV) Á NS1 0 Á Type I interferon (IFN-I) Á Immune evasion Electronic supplementary material The online version of this article (

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“…On the other hand, the cellular factor tripartite motif-containing protein 25 (TRIM52) interacts with and degrades JEV NS2A, which results in the inhibition of JEV replication [ 40 ]. Furthermore, the nucleotide sequence of the JEV NS2A-coding region is also involved in the expression of the NS1’ protein [ 41 , 42 ]. In dengue virus NS2A, the N-terminal 68 amino acids are located in the ER lumen, the core region (amino acids 69 to 209) integrally spans the ER membrane, and the C-terminal tail (amino acids 210 to 218) is located in the cytosol [ 43 ].…”

Section: Discussionmentioning

confidence: 99%

Amino Acid at Position 166 of NS2A in Japanese Encephalitis Virus (JEV) Is Associated with In Vitro Growth Characteristics of JEV

Tajima

Taniguchi

Nakayama

et al. 2020

Viruses

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We previously showed that the growth ability of the Japanese encephalitis virus (JEV) genotype V (GV) strain Muar is clearly lower than that of the genotype I (GI) JEV strain Mie/41/2002 in murine neuroblastoma cells. Here, we sought to identify the region in GV JEV that is involved in its low growth potential in cultured cells. An intertypic virus containing the NS1-3 region of Muar in the Mie/41/2002 backbone (NS1-3Muar) exhibited a markedly diminished growth ability in murine neuroblastoma cells. Moreover, the growth rate of a Muar NS2A-bearing intertypic virus (NS2AMuar) was also similar to that of Muar in these cells, indicating that NS2A of Muar is one of the regions responsible for the Muar-specific growth ability in murine neuroblastoma cells. Sequencing analysis of murine neuroblastoma Neuro-2a cell-adapted NS1-3Muar virus clones revealed that His-to-Tyr mutation at position 166 of NS2A (NS2A166) could rescue the low replication ability of NS1-3Muar in Neuro-2a cells. Notably, a virus harboring a Tyr-to-His substitution at NS2A166 (NS2AY166H) showed a decreased growth ability relative to that of the parental virus Mie/41/2002, whereas an NS2AMuar-based mutant virus, NS2AMuar-H166Y, showed a higher growth ability than NS2AMuar in Neuro-2a cells. Thus, these results indicate that the NS2A166 amino acid in JEV is critical for the growth and tissue tropism of JEV in vitro.

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The A66G back mutation in NS2A of JEV SA 14 -14-2 strain contributes to production of NS1′ protein and the secreted NS1′ can be used for diagnostic biomarker for virulent virus infection

Cited by 13 publications

References 39 publications

The molecular determinants governing the immunogenicity of Japanese encephalitis live attenuated vaccines

The molecular determinants governing the immunogenicity of Japanese encephalitis live attenuated vaccines

Japanese Encephalitis Virus NS1′ Protein Antagonizes Interferon Beta Production

Amino Acid at Position 166 of NS2A in Japanese Encephalitis Virus (JEV) Is Associated with In Vitro Growth Characteristics of JEV

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