title: Coxsackievirus B3-induced cellular protrusions: structural characteristics and functional competence.
abstract: Virus-induced alterations in cell morphology play important roles in the viral life cycle. To examine the intracellular events of coxsackievirus B3 (CVB3) infection, green monkey kidney (GMK) cells were either inoculated with the virus or transfected with the viral RNA. Various microscopic and flow cytometric approaches demonstrated the emergence of CVB3 capsid proteins at 8 h posttransfection, followed by morphological transformation of the cells. The morphological changes included formation of membranous protrusions containing viral capsids, together with microtubules and actin. Translocation of viral capsids into these protrusions was sensitive to cytochalasin D, suggesting the importance of actin in the process. Three-dimensional (3D) live-cell imaging demonstrated frequent contacts between cellular protrusions and adjacent cells. Markedly, in spite of an increase in the cellular viral protein content starting 8 h postinfection, no significant decrease in cell viability or increase in the amount of early apoptotic markers was observed by flow cytometry by 28 h postinfection. Comicroinjection of viral RNA and fluorescent dextran in the presence of neutralizing virus antibody suggested that these protrusions mediated the spread of infection from one cell to another prior to virus-induced cell lysis. Altogether, the CVB3-induced cellular protrusions could function as a hitherto-unknown nonlytic mechanism of cell-to-cell transmission exploited by enteroviruses.
authors.affiliation: Nanoscience Center, Department of Biological and Environmental Science, University of Jyväskylä, Finland.
authors.forename: Outi
authors.initials: O
authors.lastname: Paloheimo
authors.forename: Teemu O
authors.initials: TO
authors.lastname: Ihalainen
authors.forename: Sisko
authors.initials: S
authors.lastname: Tauriainen
authors.forename: Outi
authors.initials: O
authors.lastname: Välilehto
authors.forename: Sanna
authors.initials: S
authors.lastname: Kirjavainen
authors.forename: Einari A
authors.initials: EA
authors.lastname: Niskanen
authors.forename: Johanna P
authors.initials: JP
authors.lastname: Laakkonen
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
authors.forename: Maija
authors.initials: M
authors.lastname: Vihinen-Ranta
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000378:metabolism*; D002460:Cell Line; D029822:Enterovirus B, Human / Q000472:pathogenicity* / Q000502:physiology / Q000528:radiation effects; D004769:Enterovirus Infections / Q000635:transmission* / Q000821:virology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007668:Kidney / Q000166:cytology / Q000648:ultrastructure* / Q000821:virology*; D008854:Microscopy, Electron; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D036022:Capsid Proteins; D014764:Viral Proteins