Characterization of nonstructural protein 3 of a neurovirulent Japanese encephalitis virus strain isolated from a pig

ABSTRACT Flavivirus NS1 is a nonstructural protein involved in virus replication and regulation of the innate immune response. Interestingly, a larger NS1-related protein, NS1′, is often detected during infection with the members of the Japanese encephalitis virus serogroup of flaviviruses. However, how NS1′ is made and what role it performs in the viral life cycle have not been determined. Here we provide experimental evidence that NS1′ is the product of a −1 ribosomal frameshift event that occurs at a conserved slippery heptanucleotide motif located near the beginning of the NS2A gene and is stimulated by a downstream RNA pseudoknot structure. Using site-directed mutagenesis of these sequence elements in an infectious clone of the Kunjin subtype of West Nile virus, we demonstrate that NS1′ plays a role in viral neuroinvasiveness.

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Characterization of Japanese encephalitis virus envelope protein expressed by recombinant baculoviruses

Virology ◽

10.1016/0042-6822(89)90580-1 ◽

1989 ◽

Vol 173 (2) ◽

pp. 674-682 ◽

Cited By ~ 30

Author(s):

Yoshiharu Matsuura ◽

Michiko Miyamoto ◽

Takanori Sato ◽

Chiharu Morita ◽

Kotaro Yasui

Keyword(s):

Japanese Encephalitis Virus ◽

Japanese Encephalitis ◽

Envelope Protein ◽

Encephalitis Virus ◽

Recombinant Baculoviruses ◽

Virus Envelope ◽

Virus Envelope Protein

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Nonstructural Protein 1-Specific Immunoglobulin M and G Antibody Capture Enzyme-Linked Immunosorbent Assays in Diagnosis of Flaviviral Infections in Humans

Journal of Clinical Microbiology ◽

10.1128/jcm.02735-14 ◽

2014 ◽

Vol 53 (2) ◽

pp. 557-566 ◽

Cited By ~ 17

Author(s):

Day-Yu Chao ◽

Jedhan Ucat Galula ◽

Wen-Fan Shen ◽

Brent S. Davis ◽

Gwong-Jen J. Chang

Keyword(s):

West Nile Virus ◽

Japanese Encephalitis Virus ◽

Japanese Encephalitis ◽

Nonstructural Protein ◽

Encephalitis Virus ◽

Igg Antibody ◽

West Nile ◽

Dengue Viruses ◽

Nonstructural Protein 1 ◽

Antibody Capture

IgM antibody- and IgG antibody-capture enzyme-linked immunosorbent assays (MAC/GAC-ELISAs) targeted at envelope protein (E) of dengue viruses (DENV), West Nile virus, and Japanese encephalitis virus (JEV) are widely used as serodiagnostic tests for presumptive confirmation of viral infection. Antibodies directed against the flavivirus nonstructural protein 1 (NS1) have been proposed as serological markers of natural infections among vaccinated populations. The aim of the current study is to optimize an IgM and IgG antibody-capture ELISA (MAC/GAC-ELISA) to detect anti-NS1 antibodies and compare it with anti-E MAC/GAC-ELISA. Plasmids to express premembrane/envelope (prM/E) or NS1 proteins of six medically important flaviviruses, including dengue viruses (DENV-1 to DENV-4), West Nile virus (WNV), and Japanese encephalitis virus (JEV), were constructed. These plasmids were used for the production of prM/E-containing virus-like particles (VLPs) and secreted NS1 (sNS1) from COS-1 cells. Archived clinical specimens from patients with confirmed DENV, JEV, and WNV infections, along with naive sera, were subjected to NS1-MAC/GAC-ELISAs before or after depletion of anti-prM/E antibodies by preabsorption with or without VLPs. Human serum specimens from previously confirmed DENV infections showed significantly enhanced positive-to-negative (P/N) ratios for NS1-MAC/GAC-ELISAs after the depletion of anti-prM/E antibodies. No statistical differences in sensitivities and specificities were found between the newly developed NS1- and VLP-MAC/GAC-ELISAs. Further application of the assays to WNV- and JEV-infected serum panels showed similar results. A novel approach to perform MAC/GAC-ELISAs for NS1 antibody detection was successfully developed with great potential to differentiate antibodies elicited by the tetravalent chimeric yellow fever-17D/dengue vaccine or DENV infection.

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