Introduction: Dengue virus (DENV), the causative agent of dengue disease exists in sylvatic and endemic ecotypes. The cell morphological changes and viral morphogenesis of two dengue ecotypes were examined at the ultrastructural level to identify potential similarities and differences in the surrogate model of enzootic host. Materials and Methods: Vero cells were inoculated with virus at a multiplicity of infection (MOI) of 0.1. Cell cultures were harvested over a time course and processed for transmission electron microscopic imaging. Results: The filopodia protrusions on cell periphery preceded virus entry. Additionally, sylvatic DENV infection was found spreading slower than the endemic DENV. Morphogenesis of both dengue ecotypes was alike but at different level of efficiency in the permissive cells. Conclusions: This is the first ultrastructural study on sylvatic DENV and this comparative study revealed the similarities and differences of cellular responses and morphogenesis of two dengue ecotypes in vitro. The study revealed the weaker infectivity of sylvatic DENV in the surrogate model of enzootic host, which supposed to support better replication of enzootic DENV than endemic DENV.
; viral morphogenesis

Japanese encephalitis virus (JEV) is one of the most important human pathogens, which causes the permanent neuropsychiatric sequelae and even fatal diseases with high mortality and morbidity, especially among children. In this study, we expressed the structural proteins (C, prM, and E) of JEV using a Sindbis virus-based heterologous gene expression vector, the pSinRep5. We designed two expression vectors (pSinRep5/JEV C-E and pSinRep5/JEV C-NS1), which encode the precise coding sequence of JEV C-E and JEV C-NS1 proteins, respectively. These cloned JEV structural protein genes were designed to express under the Sindbis virus subgenomic promoter. Upon the transfection and expression of the pSinRep5/JEV C-E or pSinRep5/JEV C-NS1 plasmid, the transfected cells expressed approximately 55 kDa JEV E prtiens. As designed, the JEV NS1 proteins were expressed only in the SinRep5/JEV C-NS1 RNAtransfected cells. In addition, we found in the pSinRep5/JEV C-NS1-transfected cells that the viral proteins were predominantly localized around the perinuclear membranes. On the other hand, cytoplasmic staining was mainly observed in the pSinRep5/JEV C-E RNA-transfected cells in the absence of NS1 protein. Thus, our system will provide a useful tool to dissect intracellular membrane localization signals located in the JEV structural proteins without handling the infectious JEV viral particles and to characterize viral morphogenesis of this pathogen.
Asian Continental Ancestry Group* ; Child ; Clinical Coding ; Clone Cells ; Cytoplasm ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Flavivirus ; Gene Expression ; Hand ; Humans ; Intracellular Membranes ; Membranes ; Morphogenesis ; Mortality ; Plasmids ; Sindbis Virus ; Transfection ; Viral Proteins ; Virion