Nuclear Entry of Hepatitis B Virus Capsids Involves Disintegration to Protein Dimers followed by Nuclear Reassociation to Capsids

PLoS Pathogens

Michael Kann¹  Birgit Rabe¹  Andreas Bischof¹  Paul Pumpens²  Irina Sominskaya²  Christian Cazenave³  Michael Foss³  Michel Castroviejo³  Mildred Delaleau³ 

[1] Institute of Virology, Justus Liebig University, Giessen, Germany;Latvian Biomedical Research and Study Centre, Riga, Latvia;UMR 5234 CNRS-University Bordeaux 2 MCMP, Bordeaux, France

关键词: Capsids;    Ribonucleases;    Nuclear import;    Antibodies;    Dimers (Chemical physics);    Hepatitis B virus;    Agarose gel electrophoresis;    Centrifugation;   

DOI  :  10.1371/journal.ppat.1000563

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Assembly and disassembly of viral capsids are essential steps in the viral life cycle. Studies on their kinetics are mostly performed in vitro, allowing application of biochemical, biophysical and visualizing techniques. In vivo kinetics are poorly understood and the transferability of the in vitro models to the cellular environment remains speculative. We analyzed capsid disassembly of the hepatitis B virus in digitonin-permeabilized cells which support nuclear capsid entry and subsequent genome release. Using gradient centrifugation, size exclusion chromatography and immune fluorescence microscopy of digitonin-permeabilized cells, we showed that capsids open and close reversibly. In the absence of RNA, capsid re-assembly slows down; the capsids remain disintegrated and enter the nucleus as protein dimers or irregular polymers. Upon the presence of cellular RNA, capsids re-assemble in the nucleus. We conclude that reversible genome release from hepatitis B virus capsids is a unique strategy different from that of other viruses, which employs irreversible capsid destruction for genome release. The results allowed us to propose a model of HBV genome release in which the unique environment of the nuclear pore favors HBV capsid disassembly reaction, while both cytoplasm and nucleus favor capsid assembly.

【 授权许可】

CC BY