Expression of cloned envelope protein genes from the flavivirus tick-borne encephalitis virus in mammalian cells and random mutagenesis by PCR

Virus Genes ◽  
1994 ◽  
Vol 8 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Steven L. Allison ◽  
Christian W. Mandl ◽  
Christian Kunz ◽  
Franz X. Heinz
Keyword(s):  
Envelope Protein ◽  
Mammalian Cells ◽  
Random Mutagenesis ◽  
Encephalitis Virus ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

scholarly journals N-linked glycan in tick-borne encephalitis virus envelope protein affects viral secretion in mammalian cells, but not in tick cells

2013 ◽  
Vol 94 (10) ◽  
pp. 2249-2258 ◽  
Author(s):  
Kentaro Yoshii ◽  
Natsumi Yanagihara ◽  
Mariko Ishizuka ◽  
Mizuki Sakai ◽  
Hiroaki Kariwa
Keyword(s):  
Envelope Protein ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Consensus Sequence ◽  
Encephalitis Virus ◽  
Secretory Process ◽  
Virus Envelope ◽  
Tick Borne Encephalitis ◽  
Virus Envelope Protein ◽  
Tick Borne Encephalitis Virus

Tick-borne encephalitis virus (TBEV) is a zoonotic disease agent that causes severe encephalitis in humans. The envelope protein E of TBEV has one N-linked glycosylation consensus sequence, but little is known about the biological function of the N-linked glycan. In this study, the function of protein E glycosylation was investigated using recombinant TBEV with or without the protein E N-linked glycan. Virion infectivity was not affected after removing the N-linked glycans using N-glycosidase F. In mammalian cells, loss of glycosylation affected the conformation of protein E during secretion, reducing the infectivity of secreted virions. Mice subcutaneously infected with TBEV lacking protein E glycosylation showed no signs of disease, and viral multiplication in peripheral organs was reduced relative to that with the parental virus. In contrast, loss of glycosylation did not affect the secretory process of infectious virions in tick cells. Furthermore, inhibition of transport to the Golgi apparatus affected TBEV secretion in mammalian cells, but not in tick cells, indicating that TBEV was secreted through an unidentified pathway after synthesis in endoplasmic reticulum in tick cells. These results increase our understanding of the molecular mechanisms of TBEV maturation.

scholarly journals Mapping of Functional Elements in the Stem-Anchor Region of Tick-Borne Encephalitis Virus Envelope Protein E

1999 ◽  
Vol 73 (7) ◽  
pp. 5605-5612 ◽  
Author(s):  
Steven L. Allison ◽  
Karin Stiasny ◽  
Konrad Stadler ◽  
Christian W. Mandl ◽  
Franz X. Heinz
Keyword(s):  
Amino Acids ◽  
Membrane Fusion ◽  
Envelope Protein ◽  
Molecular Mechanisms ◽  
Low Ph ◽  
Encephalitis Virus ◽  
E Proteins ◽  
Functional Elements ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

ABSTRACT Envelope protein E of the flavivirus tick-borne encephalitis virus mediates membrane fusion, and the structure of the N-terminal 80% of this 496-amino-acid-long protein has been shown to differ significantly from that of other viral fusion proteins. The structure of the carboxy-terminal 20%, the stem-anchor region, is not known. It contains sequences that are important for membrane anchoring, interactions with prM (the precursor of membrane protein M) during virion assembly, and low-pH-induced structural changes associated with the fusion process. To identify specific functional elements in this region, a series of C-terminal deletion mutants were constructed and the properties of the resulting truncated recombinant E proteins were examined. Full-length E proteins and proteins lacking the second of two predicted transmembrane segments were secreted in a particulate form when coexpressed with prM, whereas deletion of both segments resulted in the secretion of soluble homodimeric E proteins. Sites located within a predicted α-helical region of the stem (amino acids 431 to 449) and the first membrane-spanning region (amino acids 450 to 472) were found to be important for the stability of the prM-E heterodimer but not essential for prM-mediated intracellular transport and secretion of soluble E proteins. A separate site in the stem, also corresponding to a predicted α-helix (amino acids 401 to 413), was essential for the conversion of soluble protein E dimers to a homotrimeric form upon low-pH treatment, a process resembling the transition to the fusogenic state in whole virions. This functional mapping will aid in the understanding of the molecular mechanisms of membrane fusion and virus assembly.

scholarly journals Identification of host antiviral genes differentially induced by clinically diverse strains of Tick-Borne Encephalitis Virus

2021 ◽  
Author(s):  
Niluka Goonawardane ◽  
Laura Upstone ◽  
Mark Harris ◽  
Ian M Jones
Keyword(s):  
Mammalian Cells ◽  
Encephalitis Virus ◽  
Therapeutic Interventions ◽  
Virus Genotype ◽  
Northern Asia ◽  
Tick Borne Encephalitis ◽  
Novel Host ◽  
Tick Borne Encephalitis Virus ◽  
Positive Strand Rna ◽  
Tbev Infection

AbstractTick Borne Encephalitis Virus (TBEV) is an important human arthropod-borne virus, which causes tick-borne encephalitis (TBE), an acute viral infection of the central nervous system (CNS) that causes neurological symptoms of varying severity. TBEV is prevalent in large parts of central- and northern-Europe as well as Northern Asia, and strains of varying pathogenicity have been described. Both host and viral specific characteristics have been postulated to determine the outcome of TBEV infection, but the exact basis of their clinical variability remains undefined.Here, we report the generation of Spinach RNA aptamer labelled TBEV replicons of high (Hypr) and low (Vs) pathogenicity isolates and perform the first direct comparison of both strains in cell culture. We show that pathogenic Hypr replicates to higher levels than Vs in mammalian cells, but not in arthropod cells, and that the basis of this difference maps to the NS5 region, encoding the methyltransferase and RNA polymerase. For both Hypr and Vs strains, NS5 and the viral genome localized to defined intracellular structures typical of positive strand RNA viruses, but Hypr was associated with significant activation of IRF-3, caspase-3 and caspase-8, whilst Vs activated Akt, affording protection against caspase-mediated apoptosis. Activation of TIAR and the formation of cytoplasmic stress granules were an additional early feature of Vs but not Hypr replication. Taken together, these findings highlight NS5 and novel host cell responses as key underling factors for the differential clinical characteristics of TBEV strains.ImportanceTick-borne encephalitis virus (TBEV) is an emerging virus of the flavivirus family spread by ticks. Tick bite can transfer the virus and lead to a febrile infection, Tick-borne encephalitis, of varying severity. There is no specific therapeutic treatment and control in endemic areas is by vaccination. The basis of the different pathologies shown following TBEV infection, from mild to fatal, is not clear although the virus genotype clearly has a role. Mapping the basis of their differential effects would allow focus on the stages of the replication cycle responsible, which might guide the development of therapeutic interventions or the creation of purposefully attenuated strains as candidate vaccines.

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