Biology Reference
In-Depth Information
Chapter 16
Virus-like Particles of Fish Nodavirus
Chan-Shing Lin
*
Betanodaviruses are causative agents of neurological disorders in several
species of fish. I reviewed the existing research on the structure of the fish
nodavirus. We sequenced and expressed the RNA2 segment of two grouper
viruses isolated from
Epinephelus malabaricus
(malabaricus grouper nervous
necrosis virus, MGNNV) and
Epinephelus lanceolatus
(dragon grouper
nervous necrosis virus, DGNNV). Comparing the ORF with striped jack
nervous necrosis virus, Atlantic halibut virus, sea bass encephalitis virus, and
greasy grouper nervous necrosis virus (GGNNV), the analysis revealed that
the Japanese SJNNV differed significantly from its geographical neighbors,
the Taiwanese MGNNV and DGNNV, particularly in the variable region.
In contrast, the geographically proximal European DlEV and AHV showed
a higher degree of similarity with each other and the Taiwanese viruses. This
suggests that host-dependent selection impacts more significantly on evolu-
tion than geographically related conditions such as water temperature. The
capsid proteins of MGNNV and DGNNV can form virus-like particles
(VLPs) in Sf 21 cells with a recombinant baculovirus system and
E. coli
. An
image reconstruction with electron cryomicroscopy data revealed a mor-
phology of the VLPs consistent with
T
3 quasi-symmetry, but with features
significantly different from insect nodavirus structures at the same resolu-
tion. This assembly system allows the first biophysical comparisons of fish
and insect nodavirus structure, assembly, and stability. The cryoEM struc-
ture at 23 Å resolution, sequence comparison, and protein fold recognition
=
* The Department of Marine Biotechnology and Resources, National Sun Yat-sen University,
Kaohsiung, TAIWAN 804.
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