Structure of Hepatitis E Virion-sized Particle Reveals an RNA-dependent Viral Assembly Pathway

Li Xing; Tian-Cheng Li; Naoyuki Mayazaki; Martha N. Simon; Joseph S. Wall; Mary Moore; Che-Yen Wang; Naokazu Takeda; Takaji Wakita; Tatsuo Miyamura; R. Holland Cheng

doi:10.1074/jbc.M110.106336

Structure of Hepatitis E Virion-sized Particle Reveals an RNA-dependent Viral Assembly Pathway*

From the ^‡Department of Molecular and Cellular Biology, University of California, Davis, California 95616,
the ^§Structural Virology Section, Karolinska Institute, Huddinge University Hospital, SE-14186 Stockholm, Sweden,
the ^¶Department of Virology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan, and
the ^‖Biology Department, Brookhaven National Laboratory, Upton, New York 11973-5000

2 To whom correspondence should be addressed. Dept. of Molecular and Cellular Biology, University of California, Davis CA 95616. Tel.: 530-752-2693; Fax: 530-752-5659; E-mail: rhch{at}ucdavis.edu.

↵1 Both authors contributed equally to this work.

Abstract

Hepatitis E virus (HEV) induces acute hepatitis in humans with a high fatality rate in pregnant women. There is a need for anti-HEV research to understand the assembly process of HEV native capsid. Here, we produced a large virion-sized and a small T=1 capsid by expressing the HEV capsid protein in insect cells with and without the N-terminal 111 residues, respectively, for comparative structural analysis. The virion-sized capsid demonstrates a T=3 icosahedral lattice and contains RNA fragment in contrast to the RNA-free T=1 capsid. However, both capsids shared common decameric organization. The in vitro assembly further demonstrated that HEV capsid protein had the intrinsic ability to form decameric intermediate. Our data suggest that RNA binding is the extrinsic factor essential for the assembly of HEV native capsids.

Footnotes

↵* This work was supported, in whole or in part, by a grant from the National Institutes of Health Roadmap Project on Nanomedicine (to R. H. C.). This work was also supported by grants from the U. S. Department of Agriculture Hatch Fund, STINT Foundation, and Strategic Research Foundation (to R. H. C.). This study was also partly funded by a grant from the Swedish Research Council (to L. X.) and grants for Research on Emerging and Re-emerging Infectious Diseases, Research on Hepatitis, and Research on Food Safety from the Ministry of Health, Labor, and Welfare, Japan (to T.- C. L.).
The atomic coordinates and structure factors (codes 2ZZQ and 3IYO) have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/).
The EM data reported in this paper have been submitted to the Electron Microscopy Data Bank (Electron Microscopy Data Bank) with accession number EMD-5173.
↵ The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. 1–4 and supplemental Table 1.