Role of VP30 Phosphorylation in Ebola Virus Nucleocapsid Assembly and Transport
Yuki Takamatsu, Tomoki Yoshikawa, Takeshi Kurosu, Shuetsu Fukushi, Noriyo Nagata, Masayuki Shimojima, Hideki Ebihara, Masayuki Saijo, Takeshi Noda
Abstract
Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.