• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.151-155
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• 2009

Hepatitis C virus (HCV) has genetic diversity like most of RNA viruses. HCV major genotypes are classified into several subtypes which are further divided into quasispecies having, genetically different but closely related variants. The HCV core that is a nucleocapsid protein located at the amino terminus of the viral polyprotein is relatively a conserved protein among the HCV isolates and thus it has been one of plausible targets for anti-HCV drug development. However, different quasispecies of HCV core gene have also been found. In this study, we compared the expression level of core protein between two different quasispecies of HCV genotype 1b. Our data demonstrate that a little differences of amino acid sequence lead to substantial difference of expression level. It might be another important reason of different pathogenesis among HCV infected patients.

• The Plant Pathology Journal
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• v.19 no.4
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• pp.210-216
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• 2003

This study examined the existence of genetically diverse population of Cucumber mosaic virus (CMV), known as quasispecies, from lily, Nicotiana benthamiana and from purified virions. Based on the conserved sequences of CMV lily isolates in intergenic region (IR) on RNA3, the genetic variation of IR from three different sources was investigated by a specific restriction endonuclease hydrolysis of amplified reverse transcription-polymerase chain reaction (RT-PCR) products using virus-specific primers, and was compared with IR sequences. The IR nucleotide sequences of CMV lily isolates were highly conserved, however, quasispecies was detected from all three sources in low level, containing sub-populations of RNA3. These subpopulations of RNA3 were inoculated onto zucchini squash by in vitro transcripts from corresponding full-length cDNA clones together with Eny RNA1 and 2 transcripts. The systemic symptom of zucchini plants infected by these quasispecies was chlorotic spotting, which was milder than severe mosaic and stunt symptom caused by Eny-CMV. The severity of symptom was correlated with RNA accumulation of viruses. These results suggest that the genome of CMV lily isolates consists of quasispecies populations.

• Journal of Microbiology
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• v.34 no.2
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• pp.166-171
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• 1996

Genetic analysis was conducted on newly isolated coliphages form soil by using a RAPD assay. From the initial result, the coliphages were turned out to be different form one another but were closely related to .psi..lambda. due to the fact that they shared the samed RAPD maker in which other T phage testings failed to show. By using the primers EC01 or EC02, a fast genetic mutation of .psi.C1 was found by producing specific RAPD markers on the phages from the first filial progeny to the second filial progeny. When we made a RAPD assay with combined primers (EC01, EC05 and EC08), the genetic mutation was again confirmed in .psi.C1. The assay detection showed mutations in other coliphages such as .psi.C2 and .psi.C3 by revealing specific RAPD bands among different progeny phages, where genetic instability of the coliphages in implied.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.110.2-111
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• 2002

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.701-704
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• 2007

This report describes the full-length sequences of 2HBV clones from a hepatocellular carcinoma (HCC) patient, one with preC mutation (1896A) and the other without preC mutation. The high level of discrepancy in mutation frequency between these 2 strains was observed in the Core (C) region among 4 ORFs. These data support previous results that Korean HBV strains, belonging to genotype C2, are prone to mutations. It is possible that the mutations (BCP and preC mutations) associated with the HBeAg defective production might contribute to the diversity of mutations related to HBV persistence, playing an important role in hepatocarcinogenesis in this patient.

• Research in Plant Disease
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• v.27 no.4
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• pp.137-148
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• 2021

Plant RNA viruses are one of the most destructive pathogens that cause a significant loss in crop production worldwide. They have evolved with high genetic diversity and adaptability due to the short replication cycle and high mutation rate during genome replication, which are characteristics of RNA viruses. Plant RNA viruses exist as quasispecies with high genetic diversity; thereby, a rapid population transition with new fitness can occur due to selective pressure resulting from environmental changes. Plant resistance can act as selective pressure and affect the fitness of the virus, which may lead to the emergence of resistance-breaking variants. In this paper, we introduced the evolutionary perspectives of plant RNA viruses and the driving forces in their evolution. Based on this, we discussed the mechanism of the emergence of variant viruses that overcome plant resistance. In addition, strategies for deploying plant resistance to viral diseases and improving resistance durability were discussed.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.478-487
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• 2017

Soybean is the most important legume crop in the world. Several diseases in soybean lead to serious yield losses in major soybean-producing countries. Moreover, soybean can be infected by diverse viruses. Recently, we carried out a large-scale screening to identify viruses infecting soybean using available soybean transcriptome data. Of the screened transcriptomes, a soybean transcriptome for soybean seed development analysis contains several virus-associated sequences. In this study, we identified five viruses, including soybean mosaic virus (SMV), infecting soybean by de novo transcriptome assembly followed by blast search. We assembled a nearly complete consensus genome sequence of SMV China using transcriptome data. Based on phylogenetic analysis, the consensus genome sequence of SMV China was closely related to SMV isolates from South Korea. We examined single nucleotide variations (SNVs) for SMVs in the soybean seed transcriptome revealing 780 SNVs, which were evenly distributed on the SMV genome. Four SNVs, C-U, U-C, A-G, and G-A, were frequently identified. This result demonstrated the quasispecies variation of the SMV genome. Taken together, this study carried out bioinformatics analyses to identify viruses using soybean transcriptome data. In addition, we demonstrated the application of soybean transcriptome data for virus genome assembly and SNV analysis.