• Journal of fish pathology
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• v.36 no.2
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• pp.229-238
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• 2023

In this study, the correlation between clinical changes and RSIV genome copy number was investigated to determine the quantitative criteria for the characteristics of RSIV infection. The rock bream (Oplegnathus fasciatus) was intraperitoneally injected with three different doses (1.0×10¹, 1.0×10³ and 1.0×10⁵ viral genome copies/fish) as low, medium, and high doses, respectively. The clinical signs (spleen enlargement, death) observation and real-time PCR were conducted at 5, 10 and 14 days post-injection. During the experiment, spleen index as a quantitative indicator for spleen enlargement was continuously increased in the medium- (up to 2.26) and high-dose (up to 4.99) challenge groups, respectively. Notably, when the spleen index was over 1.5, 2.0, 2.5 and 3.0, a positive correlation was revealed with average viral genome copy numbers of 2.51, 3.37, 4.97 and 5.43×10⁷ viral genome copies/mg, respectively. Moreover, the threshold of spleen index over 1.5 was 1.0×10⁶ viral genome copies/mg, while the thresholds of spleen index over 2.0 and dead was 2.51×10⁷ viral genome copies/mg and the thresholds of spleen index over 2.5 and 3 was 3.98×10⁷ viral genome copies/mg. These findings suggest the possibility of quantitatively analyzing the characteristics and development process of RSIV infection.

• Genomics & Informatics
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• v.6 no.1
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• pp.54-58
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• 2008

Genotyping Tool for Viral SEQuences (GTVseq) provides scientists with the genotype information on the viral genome sequences including HIV-1, HIV-2, HBV, HCV, HTLV-1, HTLV-2, poliovirus, enterovirus, flavivirus, Hantavirus, and rotavirus. GTVseq produces alternative and additive genotype information for the query viral sequences based on two different, but related, scoring methods. The genotype information produced is reported in a graphical manner for the reference genotype matches and each graphical output is linked to the detailed sequence alignments between the query and the matched reference sequences. GTVseq also reports the potential 'repeats' and/or 'recombination' sequence region in a separated window. GTVseq does not replace completely other well-known genotyping tools such as NCBI's virus sequence genotyping tool (http://www.ncbi. nlm.nih.gov/projects/genotyping/formpage.cgi), but provides additional information useful in the confirmation or for further investigation of the genotype(s) for the newly isolated viral sequences.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.10a
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• pp.66-77
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• 2000

For a variety of viruses, the primary virus infection has been shown to prevent superinfection with a homologous secondary virus; however, the mechanism of exclusion has not been clearly understood. In this work, we demonstrated that BVDV -infected MDBK cells were protected from superinfection with a homologous superinfecting BVDV, one of the positive-sense RNA pestiviruses, but not with an unrelated rhabdovirus, such as vesicular stomatitis virus. Once superinfection exclusion was established by a primary infection with BVDV, the transfected infectious BVD viral RNA genome was shown to be competent for viral translation, but not viral replication. In addition, our results also demonstrated that upon superinfection, the. viral RNA genome of viral particles was not transferred into the cytoplasm of BVDV -infected cells. Using newly developed system involving rapid generation of the MDBK cells expressing BVD viral proteins, we subsequently found that expression of the viral structural proteins was dispensable for the block occurring at the level of viral RNA replication, but required for the exclusion at the level of viral entry step. Altogether, these findings provide evidence that the superinfection exclusion of BVDV occurs not only at the level of viral replication in which the viral replicase are involved, but also at the level of viral entry with which the viral structural proteins are associated, and that a cellular factor(s) play an essential role in this process.

• BMB Reports
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• v.55 no.12
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• pp.587-594
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• 2022

A persistent DNA tumor virus infection transforms normal cells into cancer cells by either integrating its genome into host chromosomes or retaining it as an extrachromosomal entity called episome. Viruses have evolved mechanisms for attaching episomes to infected host cell chromatin to efficiently segregate the viral genome during mitosis. It has been reported that viral episome can affect the gene expression of the host chromosomes through interactions between viral episomes and epigenetic regulatory host factors. This mini review summarizes our current knowledge of the tethering sites of viral episomes, such as EBV, KSHV, and HBV, on host chromosomes analyzed by three-dimensional genomic tools.

• Journal of fish pathology
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• v.34 no.1
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• pp.1-7
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• 2021

Red sea bream iridovirus (RSIV), belonging to the genus Megalocytivirus, is the predominant cause of mortality in marine fishes in Korea, including rock bream (Oplegnathus fasciatus). Rockfish (Sebastes schlegelii) are the host fish for RSIV, exhibiting no clinical signs or mortality. Cohabitation challenges, which mimicked natural transmission conditions, were performed to evaluate viral transmission between rock bream and rockfish, and to determine the pathogenicity and viral loads. In cohabitation challenge, artificially RSIV-infected rock bream were the viral donor, and healthy rockfish were the recipient. The results showed that although the donor rock bream had 95-100 % cumulative mortality (>10⁸ viral genome copies/mg of spleen 7-14 days after viral infection), the recipient rockfish did not die, even when the viral genome copies in the spleen were >10⁵ copies/mg. These results indicated asymptomatic infections. Notably, in a reverse-cohabitation challenge (artificially RSIV-infected rockfish as the viral donor and healthy rock bream as the recipient), RSIV horizontally infected from subclinical rockfish to rock bream (10⁷ viral genome copies/mg of spleen 21 days after cohabitation) with 10-20% cumulative mortality. These results suggest that an asymptomatic, infected rockfish can naturally transmit the RSIV without being sacrificed.

• Genomics & Informatics
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• v.20 no.3
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• pp.37.1-37.1
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• 2022

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.241-259
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• 2006

Polydnavirus is a mutualistic DNA virus found in some braconid and ichneumonid wasps. Its genome is integrated into host chromosome as a provirus. Its replication occurs at ovarian calyx epithelium during host pupal stage to form episomal viral particles. The viral particles are delivered into hemocoel of the parasitized insect along with eggs during wasp oviposition. Several polydnaviral genomes, which are isolated from the episomal virus particles, have been sequenced and exhibit some gene families with speculative physiological functions. This review presents the viral characteristics in terms of Its parasitic physiology. For developing new insect pest control tactics, it also discusses several application strategies exploiting the viral genome to manipulate insect physiology.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.118-120
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• 2002

Genetic materials including DNA plasmid are effective delivery vehicle to express interesting gene efficiently and safely not to generate replication competent virus. Moreover, it has advantages to design a better vector and to simplify manufacturing and storage condition. To understand a possible pathogenic mechanism by a flavivirus, West Nile virus (WNV), WNV genome sequence was aligned to other pathogenic viral genome. Interestingly, WNV capsid (Cp) amino acid sequence has some homology to HIV-l Vpr protein. These proteins induce apoptosis in human cell lines as well as in vivo and cell cycle arrest. Therefore, DNA plasmid carrying apoptosis-inducing and cell cycle arresting viral proteins including a HIV-1 Vpr and a WNV Cp protein can be useful for anti-cancer therapeutic applications. This WNV Cp protein is an early expressed protein which can be a reasonable target antigen (Ag) for vaccine design. Immunization of a DNA construct encoding WNV Cp protein induces a strong Ag-specific humoral and Th1-type immune responses in animal. Therefore, DNA plasmid encoding apoptotic viral proteins can be useful tool for therapeutic and prophylactic applications.

• The Journal of Korean Society of Virology
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• v.30 no.1
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• pp.39-49
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• 2000

The genome of Hantaan virus, the prototype of the hantavirus genus, is composed of three segmented, single stranded negative sense RNA genome. The 5' and 3' termini of the Hantaan virus RNA genome contain noncoding regions (NCRs) that are highly conserved and complementary to form panhandle structures. There are some reports that these NCRs seems to control gene expression and viral replication in influenza virus and vesicular stomatitis virus. In this study, we examined whether NCRs in Hantaan virus playa role in expression of the viral nucleocapsid protein (Np) and foreign (luciferase) gene. The 5' and/or 3' NCR-deleted mutants were constructed and analysed. The Np expression of 5' NCR-deleted clone was similar to that of the clone containing full S genome. In the case of 3' NCR-deleted clone, it showed 40% reduction. To investigate the role of NCR in foreign gene expression, the clones which are replaced ORF of Hantaan viral Np gene with that of luciferase gene were constructed. The results were similar to those of the experiments using Np gene. These results suggest that 3' NCR is more important than 5' NCR in protein expression. To find out a critical region of 3' NCR in protein expression, several clones with a deleted part of 3' NCR were constructed and analyzed. The deletion of the conserved region in 3' NCR showed $20{\sim}30%$ decrease in Np expression. However there were no change in luciferase activities between clones with or without non-conserved region of 3' NCR. These results suggest that the 3' NCR of Hantaan virus S genome, especially conserved region in 3' NCR, plays an important role in the expression of Hantaan viral Np and foreign genes.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.113.1-113
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• 2003

A potexvirus, Hosta virus X (HVX-Kr), causing mosaic and mottle symptoms was isolated from hosta plants (Hosta spp.), and its entire genome RNA sequence was determined. in Korea using cDNA library and RACE methods. The genome of HVX encodes five open reading frames coding for viral replicase, triple gene block (TGB), and viral coat protein (CP) from the 5'to 3' ends, which is a typical genome structure of potexviruses. The 3-terminal region of the virus includes the TGBI (26 kDa), TGB2 (13 kDa), TGB3 (8 kDa), and 23 kDa coat protein (CP) and the 3-nontranslated region (NTR). The CP gene of the type isolate of HVX (HVX-U) was amplified by RT-PCR and its nucleotide sequence was determined. The CPs of HVX-Kr and HVX-U had 100％ and 98.9％ identical amino acids and nucleotides, respectively. Most of the regions of the genome HVX had over 50％ nucleotide identical to other sequenced potexviruses. This is the first report of complete genome sequence information of HVX and molecular evidence supporting the virus as a distinct species of the genus Potexvirus.