The infectious particle of insect-borne totivirus-like Omono River virus has raised ridges and lacks fibre complexes.
Omono River virus (OmRV) is a double-stranded RNA virus isolated from Culex mosquitos, and it belongs to a group of unassigned insect viruses that appear to be related to Totiviridae. This paper describes electron cryo-microscopy (cryoEM) structures for the intact OmRV virion to 8.9 Å resolution and the structure of the empty virus-like-particle, that lacks RNA, to 8.3 Å resolution. The icosahedral capsid contains 120-subunits and resembles another closely related arthropod-borne totivirus-like virus, the infectious myonecrosis virus (IMNV) from shrimps. Both viruses have an elevated plateau around their icosahedral 5-fold axes, surrounded by a deep canyon. Sequence and structural analysis suggests that this plateau region is mainly composed of the extended C-terminal region of the capsid proteins. In contrast to IMNV, the infectious form of OmRV lacks extensive fibre complexes at its 5-fold axes as directly confirmed by a contrast-enhancement technique, using Zernike phase-contrast cryo-EM. Instead, these fibre complexes are replaced by a short "plug" structure at the five-fold axes of OmRV. OmRV and IMNV have acquired an extracellular phase, and the structures at the five-fold axes may be significant in adaptation to cell-to-cell transmission in metazoan hosts.
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Kenta
K
Okamoto
National Institute for Physiological Sciences (NIPS), Japan.
Naoyuki
N
Miyazaki
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Daniel S D
DS
Larsson
Department of Medical Entomology, National Institute of Infectious Diseases (NIID), Japan.
Daisuke
D
Kobayashi
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Martin
M
Svenda
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Kerstin
K
Mühlig
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Filipe R N C
FR
Maia
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Laura H
LH
Gunn
Department of Medical Entomology, National Institute of Infectious Diseases (NIID), Japan.
Haruhiko
H
Isawa
Department of Medical Entomology, National Institute of Infectious Diseases (NIID), Japan.
Mutsuo
M
Kobayashi
Department of Medical Entomology, National Institute of Infectious Diseases (NIID), Japan.
Kyoko
K
Sawabe
National Institute for Physiological Sciences (NIPS), Japan.
Kazuyoshi
K
Murata
The Laboratory of Molecular Biophysics, Department of Cell and Molecular biology, Uppsala University, Sweden.
Janos
J
Hajdu
D000330:Aedes / Q000821:virology; D000595:Amino Acid Sequence; D000818:Animals; D002213:Capsid / Q000648:ultrastructure*; D036022:Capsid Proteins / Q000737:chemistry / Q000648:ultrastructure; D002478:Cells, Cultured; D020285:Cryoelectron Microscopy; D007303:Insect Vectors / Q000821:virology; D008958:Models, Molecular; D000072417:Protein Domains; D020836:Protein Structure, Quaternary; D019196:Totiviridae / Q000648:ultrastructure*; D014771:Virion / Q000648:ultrastructure*
D036022:Capsid Proteins