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Proper maturation of the Japanese encephalitis virus envelope glycoprotein requires cosynthesis with the premembrane
Abstract:
The role of the Japanese encephalitis virus (JEV) premembrane (prM) protein in maturation of the envelope (E) glycoprotein was evaluated by using recombinant vaccinia viruses encoding E in the presence (vP829) or absence (vP658) of prM. Immunofluorescence analyses showed that E appeared to be localized in the endoplasmic reticulum of cells infected with JEV, vP829, or vP658. However, reactivity with monoclonal antibodies and behavior in Triton X-114 indicated that E produced in the absence of prM behaved abnormally. Furthermore, E produced in the presence of prM by recombinant vaccinia viruses could be incorporated into flavivirus pseudotypes, whereas E synthesized in the absence of prM could not. These results demonstrate that cosynthesis of prM is required for proper folding, membrane association, and assembly of the flavivirus E protein.
Insights
The Japanese encephalitis virus (JEV) premembrane (prM) protein is essential for the proper folding and assembly of the envelope (E) glycoprotein. Without prM, the E protein exhibits abnormal behavior and cannot form functional viral particles.
Area of Science:
- Virology
- Molecular Biology
- Protein Biochemistry
Background:
- Japanese encephalitis virus (JEV) is a significant cause of viral encephalitis globally.
- The JEV envelope (E) glycoprotein is crucial for viral entry and assembly.
- The role of the premembrane (prM) protein in E glycoprotein maturation is not fully understood.
Purpose of the Study:
- To investigate the role of the JEV prM protein in the maturation and proper folding of the E glycoprotein.
- To determine if prM is necessary for the correct membrane association and assembly of the E protein.
Main Methods:
- Utilized recombinant vaccinia viruses to express JEV E glycoprotein with or without prM.
- Employed immunofluorescence microscopy to assess E protein localization.
- Analyzed E protein conformation and membrane association using monoclonal antibody reactivity and Triton X-114 partitioning.
- Assessed the incorporation of E protein into flavivirus pseudotypes.
Main Results:
- E glycoprotein was localized to the endoplasmic reticulum in both the presence and absence of prM.
- E protein produced without prM showed abnormal reactivity with antibodies and altered membrane association.
- E protein synthesized with prM could be incorporated into flavivirus pseudotypes, unlike E protein produced without prM.
- Cosynthesis of prM is critical for the proper folding, membrane association, and assembly of the JEV E protein.
Conclusions:
- The JEV prM protein plays an indispensable role in the maturation of the E glycoprotein.
- Proper folding, membrane association, and assembly of the E protein are dependent on the presence of prM.
- These findings highlight the importance of prM in the JEV life cycle and provide insights for antiviral strategies.