ABSTRACT
Rationale: The capsid (C) protein of dengue virus functions primarily as a building block of the nucleocapsid. During virus replication, C localizes in the cytoplasm as well as nuclei of infected cells. The function of C nuclear localization remains unknown. This study aimed to investigate the localization of C in infected cells undergoing mitosis. Methods: Indirect immunofluorescence analysis was employed. Vero and PS clone D cell lines were infected with dengue viruses for 24-48 hours, fixed, permeabilized and reacted successively with antibodies specific for C and NS1, and fluorochrome-conjugated secondary antibodies. Stained cells were visualized under a fluorescence microscope. Results: During the infection with dengue serotype 2 viruses, C was detected in the cytoplasm and/or nuclei of interphase cells. In the majority of infected mitotic cells, C localized to the cytoplasm with no staining of chromosomes. In the remainder, C was found to associate with the periphery of mitotic chromosomes with less intense staining in the cytoplasm. Association of C with chromosomes, which was observed with recent clinical isolates and laboratory adapted strains, was not restricted to any specific phase of mitosis. Conclusions: Differential localization to the cytoplasm or chromosome in mitotic cells suggests the highly dynamic nature of the C protein.