• The Plant Pathology Journal
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• v.23 no.4
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• pp.272-280
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• 2007

Isolates of Cucumber mosaic virus (CMV) collected in Korea, were compared with their pathological features in tobacco and zucchini squash. Full-length cDNA clone of RNA3 was generated by using long-distance RT-PCR. Transcript RNA3 from the cDNA clone was inoculated onto host plants with transcripts RNA1 and RNA2 of Fny strain, generating RNA3-pseudorecombinant CMV. Timing and severity of systemic symptom was not significantly different among the pseudorecombinant CMVs in tobacco, compared with strains Fny-CMV and Pf-CMV. However, the pseudorecombinant CMVs induced two different systemic symptoms (mosaic vs. chlorotic spot) in zucchini squash. Based on symptom induction, the pseudorecombinant CMVs were categorized into two classes. The severity and timing of symptoms were correlated with viral RNA accumulations in systemic leaves of zucchini squash, suggesting that different kinetics of virus movement associated with CMV proteins are crucial for systemic infection and symptom development in zucchini squash. The analysis of movement proteins (MP) of CMV strains showed high sequence homology, but the differences of several amino acids were found in the C-terminal region between Class-I-CMV and Class-II-CMV. The analysis of coat proteins (CP) showed that the CMV isolates tested belonged to CMV subgroup I and the viruses shared overall 87-99% sequence identity in their genomes. Phylogenetic analysis of MP and CP suggested that biological properties of Korean CMV isolates have relationships associated with host species.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.233-239
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• 2024

N6-methyladenosine (m6A) RNA methylation has recently emerged as a significant co-transcriptional modification involved in regulating various RNA functions. It plays a vital function in numerous biological processes. Enzymes referred to as m6A methyltransferases, such as the methyltransferase-like (METTL) 3-METTL14-Wilms tumor 1 (WT1)-associated protein (WTAP) complex, are responsible for adding m6A modifications, while m6A demethylases, including fat mass and obesity-associated protein (FTO) and alkB homolog 5 (ALKBH5), can remove m6A methylation. The functions of m6A-methylated RNA are regulated through the recognition and interaction of m6A reader proteins. Recent research has shown that m6A methylation takes place at multiple sites within hepatitis B virus (HBV) RNAs, and the location of these modifications can differentially impact the HBV infection. The addition of m6A modifications to HBV RNA can influence its stability and translation, thereby affecting viral replication and pathogenesis. Furthermore, HBV infection can also alter the m6A modification pattern of host RNA, indicating the virus's ability to manipulate host cellular processes, including m6A modification. This manipulation aids in establishing chronic infection, promoting liver disease, and contributing to pathogenesis. A comprehensive understanding of the functional roles of m6A modification during HBV infection is crucial for developing innovative approaches to combat HBV-mediated liver disease. In this review, we explore the functions of m6A modification in HBV replication and its impact on the development of liver disease.

• Molecules and Cells
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• v.23 no.3
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• pp.304-315
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• 2007

Fusarium graminearum causes a serious scab disease of small grains in Korea. The nucleotide sequence of the genomic RNA of a double-stranded RNA (dsRNA) virus, Fusarium graminearum virus-DK21 (FgV-DK21), from F. graminearum strain DK21, which is associated with hypovirulence in F. graminearum, was determined and compared to the genome sequences of other mycoviruses, including Cryponectria hypoviruses. The FgV-DK21 dsRNA consists of 6,624 nucleotides, excluding the 3'-terminal poly(A) tail. The viral genome has 53- and 46-nucleotide 5' and 3' untranslated regions (UTRs), respectively, and five putative open reading frames. A phylogenetic analysis of the deduced amino acid sequence of ORF1, which encodes a putative RNA-dependent RNA polymerase, and those of other mycoviruses revealed that this organism forms a distinct virus clade with other hypoviruses, and is more distantly related to other mycoviruses (3.8 to 24.0% identity). However, pairwise sequence comparisons of the nucleotide and deduced amino acid sequences of ORFs 2 through 5 revealed no close relationships to other protein sequences currently available in GenBank. Analyses of RNA accumulation by Northern blot and primer extension indicated that these putative gene products are expressed from at least two different subgenomic RNAs (sgRNAs), in contrast to the cases in other hypoviruses. This study suggests the existence of a new, as yet unassigned, genus of mycoviruses that exhibits a potex-like genome organization and sgRNA accumulation.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.399-402
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• 1992

The causative virus causing rabbit hepatitis has been further characterized by evaluating viral proteins and viral nucleic acids of purified viruses from the liver of the experimentally infected rabbits. Rabbit hepatitis virus has one major structural protein of 54 kilodaltons and some minor proteins. Vrial RNA was resistant to DNAse I. The size of viral nucleic acid of this virus was calculated to be about 7.5 kilobases. These findings indicate that rabbit hepatitis virus belongs to the family Caliciviridae.

• Molecules and Cells
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• v.44 no.12
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• pp.911-919
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• 2021

The virus-induced genome editing (VIGE) system aims to induce targeted mutations in seeds without requiring any tissue culture. Here, we show that tobacco rattle virus (TRV) harboring guide RNA (gRNA) edits germ cells in a wild tobacco, Nicotiana attenuata, that expresses Streptococcus pyogenes Cas9 (SpCas9). We first generated N. attenuata transgenic plants expressing SpCas9 under the control of 35S promoter and infected rosette leaves with TRV carrying gRNA. Gene-edited seeds were not found in the progeny of the infected N. attenuata. Next, the N. attenuata ribosomal protein S5 A (RPS5A) promoter fused to SpCas9 was employed to induce the heritable gene editing with TRV. The RPS5A promoter-driven SpCas9 successfully produced monoallelic mutations at three target genes in N. attenuata seeds with TRV-delivered guide RNA. These monoallelic mutations were found in 2%-6% seeds among M₁ progenies. This editing method provides an alternative way to increase the heritable editing efficacy of VIGE.

• The Plant Pathology Journal
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• v.37 no.3
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• pp.258-267
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• 2021

Asian pear (Pyrus pyrifolia) is a widely cultivated and commercially important fruit crop, which is occasionally subject to severe economic losses due to latent viral infections. Thus, the aim of the present study was to examine and provide a comprehensive overview of virus populations infecting a major pear cultivar ('Singo') in Korea. From June 2017 to October 2019, leaf samples (n = 110) of pear trees from 35 orchards in five major pear-producing regions were collected and subjected to RNA sequencing. Most virus-associated contigs matched the sequences of known viruses, including apple stem grooving virus (ASGV) and apple stem pitting virus (ASPV). However, some contigs matched the sequences of apple green crinkle-associated virus and cucumber mosaic virus. In addition, three complete or nearly complete genomes were constructed based on transcriptome data and subjected to phylogenetic analyses. Based on the number of virus-associated reads, ASGV and ASPV were identified as the dominant viruses of 'Singo.' The present study describes the virome of a major pear cultivar in Korea, and looks into the diversity of viral communities in this cultivar. This study can provide valuable information on the complexity of genetic variability of viruses infecting pear trees.

• Korean Journal of Microbiology
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• v.30 no.3
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• pp.177-180
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• 1992

Among 120 U. maydis strains isolated in Korea 14 different strains containing specific viral dsRNA segments were analyzed for the distribution of dsRNA and the production of toxin protein. Several distinctive dsRNA patterns were identified, 9 cases of P type with typical H, M and L ds RNA and one case of non-P-type, the frequency of a specific isolate was decreased with increasing number of dsRNA segments. The presence of dsRNA had no effect on the cultural or morphological phenotype of the host. Two isolates containing P type dsRNA segments appeared to produce toxin protein (killer strains) which inhibited the growth of 4 isolates (sensitive strain) with different susceptibility. Two killer strains contain unique M dsRNA segment which may code for toxin protein. However, the presence of toxin-sensitive strains among dsRNA-free isolates was similar to that of ds RNA containing strains.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.31-31
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• 1996

The double-stranded panhandle structure of the influenza virus RNA is important for the replication, transcription and packaging into the virion of the vRNA. The solution structure of a 34-nucleotide-long RNA which contains the conserved panhandle sequences has been investigated by one- and two-dimensional NMR spectroscopies. (omitted)

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.361-363
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• 1996

The terminal regions of the double-stranded RNA (dsRNA) genome segments of infectious pancreatic necrosis virus (IPNV) DRT strain were sequenced. The dsRNAs, which were $^{32}P$-labelled at their 3'-termini by incubation with [$^{32}P$]pCp and T4 RNA ligase, were separated by 5$%$ polyacrylamide gel electrophoresis, and the segments A and B of IPNV-DRT were sequenced by two-dimensional gel electrophoresis. The 5'-terminal sequences of the IPNV-DRT plus strand from two genome segments were found to have the same conserved nucleotide (5'-CGG(C/A)A-), but the 3'-terminal sequences -CCCCAGGCG-3' and -CGGACCCCG-3' were found in the plus strand from segments A and B, respectively. The inverted oligonucleotide sequences of 3'-terminal of between segments A and B were found and they differ from those of other IPNVs.

• Molecules and Cells
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• v.21 no.3
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• pp.330-336
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• 2006

Since its identification in 1989, hepatitis C virus has been the subject of extensive research. The biology of the virus and the development of antiviral drugs are closely related. The RNA polymerase activity of nonstructural protein 5B was first demonstrated in 1996. NS5B is believed to localize to the perinuclear region, forming a replicase complex with other viral proteins. It has a typical polymerase structure with thumb, palm, and finger domains encircling the active site. A de novo replication initiation mechanism has been suggested. To date, many small molecule inhibitors are known including nucleoside analogues, non-nucleoside analogues, and pyrophosphate mimics. NS5B interacts with other viral proteins such as core, NS3, 4A, 4B, and 5A. The helicase activity of NS3 seems necessary for RNA strand unwinding during replication, with other nonstructural proteins performing modulatory roles. Cellular proteins interacting with NS5B include VAMP-associated proteins, heIF4AII, hPLIC1, nucleolin, PRK2, ${\alpha}$-actinin, and p68 helicase. The interactions of NS5B with these proteins might play roles in cellular trafficking, signal transduction, and RNA polymerization, as well as the regulation of replication/translation processes.