Viral Membrane Fusion and Nucleocapsid Delivery into the Cytoplasm are Distinct Events in Some Flaviviruses

PLoS Pathogens

Adel M. Nour¹  Yue Li¹  Yorgo Modis¹  Joseph Wolenski² 

[1] Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America;Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America

关键词: Membrane fusion;    Lipids;    Vero cells;    Cytoplasm;    Endosomes;    Antibodies;    Viral entry;    Nucleocapsids;   

DOI  :  10.1371/journal.ppat.1003585

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Flaviviruses deliver their genome into the cell by fusing the viral lipid membrane to an endosomal membrane. The sequence and kinetics of the steps required for nucleocapsid delivery into the cytoplasm remain unclear. Here we dissect the cell entry pathway of virions and virus-like particles from two flaviviruses using single-particle tracking in live cells, a biochemical membrane fusion assay and virus infectivity assays. We show that the virus particles fuse with a small endosomal compartment in which the nucleocapsid remains trapped for several minutes. Endosomal maturation inhibitors inhibit infectivity but not membrane fusion. We propose a flavivirus cell entry mechanism in which the virus particles fuse preferentially with small endosomal carrier vesicles and depend on back-fusion of the vesicles with the late endosomal membrane to deliver the nucleocapsid into the cytoplasm. Virus entry modulates intracellular calcium release and phosphatidylinositol-3-phosphate kinase signaling. Moreover, the broadly cross-reactive therapeutic antibody scFv11 binds to virus-like particles and inhibits fusion.

【 授权许可】

CC BY