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ID 30810
file
creator
Hata, Naomi
Iwamoto, Tokinori
Kawato, Yasuhiko
Mori, Koh-Ichiro
subject
betanodavirus
temperature sensitivity
reassortant
chimeric virus
viral growth
RNA replication
NDC
Biology
abstract
Betanodaviruses, the causative agents of viral nervous necrosis in marine fish, have bipartite positive-sense RNA genomes. The larger genomic segment, RNA1 (similar to 3.1 kb), encodes an RNA-dependent RNA polymerase (protein A), and the smaller genomic segment RNA2 (similar to 1.4 kb) codes for the coat protein. These viruses can be classified into four genotypes, designated striped jack nervous necrosis virus (SJNNV), redspotted grouper nervous necrosis virus (RGNNV), tiger puffer nervous necrosis virus (TPNNV), and barfin flounder nervous necrosis virus (BFNNV), based on similarities in their partial RNA2 sequences. The optimal temperatures for the growth of these viruses are 20-25A degrees C (SJNNV), 25-30A degrees C (RGNNV), 20A degrees C (TPNNV), and 15-20A degrees C (BFNNV). However, little is known about the mechanisms underlying the temperature sensitivity of these viruses. We first constructed two reassortants between SJNNV and RGNNV to test their temperature sensitivity. The levels of viral growth and RNA replication of these reassortants and parental viruses in cultured fish cells were similar at 25A degrees C. However, the levels of all of the viruses but RGNNV were markedly reduced at 30A degrees C. These results indicate that both RNA1 and RNA2 control the temperature sensitivity of betanodaviruses by modulating RNA replication or earlier viral growth processes. We then constructed ten mutated RGNNVs, the RNA1 segments of which were chimeric between SJNNV and RGNNV, and showed that only chimeric viruses bearing the RGNNV RNA1 region, encoding amino acid residues 1-445, grew similarly to the parental RGNNV at 30A degrees C. This portion of protein A is known to serve as a mitochondrial-targeting signal rather than functioning as an enzymatic domain.
journal title
Archives of Virology
volume
Volume 155
issue
Issue 10
start page
1597
end page
1606
date of issued
2010-10
publisher
Springer Wien
issn
0304-8608
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2010 Springer
relation
The original publication is available at www.springerlink.com
relation url
department
Graduate School of Biosphere Science