• 미생물학회지
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• 제44권4호
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• pp.293-298
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• 2008

HCV는 HIV등과 함께 수혈이나 혈장된 획물질을 통하여 감염되는 주요 바이러스이다. 주로 혈액이나 혈장에서 HCV에 대한 항체를 검출함으로서 HCV의 감염을 방지하고 있다. 그러나 바이러스에 감염되었으나 항체가 생성되기 이전이나 항체의 양이 적은 경우에는 HCV의 검출이 어렵다. 따라서 핵산중폭시험(nucleic acid amplification tests, NAT)을 이용한 HCV 유전자를 검출하려는 시도들이 진행되고 있다. 이 연구의 목적은 혈장분획물질에서 HCV RNA를 검출할 수 있는 핵산증폭시험 방법을 개발하는 것이다. 5종류의 PCR primer를선별하여 실험에 이용하였다. 혈장분획물질의 HCV RNA 추출에는 컬럼 방법을 이용하는 것이 유용한 것으로나타났다. 핵산중폭시험의 결합 온도는 $48^{\circ}C$가 가장 적절한 것으로 나타났다. 또한 2차 PCR의 경우, 1차 PCR 산물 $1{\mu}l$와 30 pmol의 primer즐 사용하였을 때 높은 민감도와 특이성을 보이는 것을 알 수 있었다. 혈장 분획물질에 HCV를 주입하여 혈장중폭시험을 수행한 결과, 100 IU/ml까지 검출 할 수 있었다. 한편 근육주사용항체(IMIG)의 경우 핵산중폭시험을 통한 검출한계는 100IU/ml로 COBAS amplicor HCV2.0의 500 IU/ml 이상의 검출한계보다 민감도가 더 높은 것으로 나타났다. 이러한 결과들로 보아 본 실험에 이용된 핵산증폭시험이 혈장분획물질에서 HCV RNA를 검출하는데 유용한 방법으로 사용될 수 있을 것으로 생각된다.

• Journal of Microbiology
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• 제42권4호
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• pp.361-364
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• 2004

Internal ribosome entry site (IRES) of the hepatitis C virus (HCV) is known to be essential for HCV replication and most conserved among HCV variants. Hence, IRES RNA is a good therapeutic target for RNA-based inhibitors, such as ribozymes. We previously proposed a new anti-HCV modulation strategy based on trans-splicing ribozymes, which can selectively replace HCV transcripts with a new RNA that exerts anti-HCV activity. To explore this procedure, sites which are accessible to ribozymes in HCV IRES were previously determined by employing an RNA mapping method in vitro. In this study, we evaluate the intracellular accessibility of the ribozymes by comparing the trans-splicing activ­ities in cells of several ribozymes targeting different sites of the HCV IRES RNA. We assessed the intra­cellular activities of the ribozymes by monitoring their target-specific induction degree of both reporter gene activity and cytotoxin expression. The ribozyme capable of targeting the most accessible site iden­tified by the mapping studies then harbored the most active trans-splicing activity in cells. These results suggest that the target sites predicted to be accessible are truly the most accessible in the cells, and thus, could be applied to the development of various RNA-based anti-HCV therapies.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.660-664
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• 2005

We have previously isolated specific RNA aptamers with high affinity against the helicase domain of hepatitis C virus (HCV) nonstructural protein 3 (NS3). The RNA aptamers competitively and efficiently inhibited the helicase activity, partially impeding HCV replicon replication in human hepatocarcinoma cells. In this study, the RNA aptamers were tested for binding to the HCV NS3 proteins in eukaryotic cells, using a yeast three-hybrid system. The aptamers were then recognized by the HCV NS3 proteins when expressed in the cells, while the antisense sequences of the aptamers were not. These results suggest that the in vitro selected RNA aptamers can also specifically bind to the target proteins in vivo. Consequently, they could be potentially utilized as anti-HCV lead compounds.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제2권1호
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• pp.109-115
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• 1999

Hepatitis C virus (HCV) has been identified as an important cause of posttransfusion hepatitis, but vertical transmission of chronic infected HCV RNA positive mothers has been documented in some cases. The reports of the risk of perinatal infection have been widely varied in the literature. The authors experienced one case of vertical transmission of HCV in an infant of a mother who had hepatitis C during pregnancy. At admission, HCV RNA (+), Ig G anti HCV (+) and Ig M anti HCV (+) were found in the mother. Also at admission, HCV RNA (+), Ig G anti HCV (+), Ig M anti HCV (+), elevation of liver aminotransferase level and hepatosplenomegaly on ultrasonography were found in the baby on day 31. HCV RNA (-), Ig M anti HCV (-) and normal of liver aminotransferase level were noted on day 250 in the serum of the infant. We used reverse transcriptase polymerase chain reaction (RT-PCR) technique to find a very small amount of HCV RNA in the serum. All the findings suggest vertical transmission of HCV RNA from mother to infant during 3rd trimester of pregnancy.

• BMB Reports
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• 제36권6호
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• pp.538-544
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• 2003

The hepatitis C virus (HCV) is a major causative agent of chronic hepatitis and hepatocellular carcinoma. The development of alternative antiviral therapies is warranted because current treatments for the HCV infection affect only a limited number of patients and lead to significant toxicities. The HCV genome is exclusively present in the RNA form; therefore, ribozyme strategies to target certain HCV sequences have been proposed as anti-HCV treatments. In this study, we determined which regions of the internal ribosome entry site (IRES) of HCV are accessible to ribozymes by employing an RNA mapping strategy that is based on a trans-splicing ribozyme library. We then discovered that the loop regions of the domain IIIb of HCV IRES appeared to be particularly accessible. Moreover, to verify if the target sites that were predicted to be accessible are truly the most accessible, we assessed the ribozyme activities by comparing not only the trans-splicing activities in vitro but also the trans-cleavage activities in cells of several ribozymes that targeted different sites. The ribozyme that could target the most accessible site identified by mapping studies was then the most active with high fidelity in cells as well as in vitro. These results demonstrate that the RNA mapping strategy represents an effective method to determine the accessible regions of target RNAs and have important implications for the development of various antiviral therapies which are based on RNA such as ribozyme, antisense, or siRNA.

• BMB Reports
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• 제30권3호
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• pp.234-236
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• 1997

Chronic hepatitis C virus (HCV) infection is associated with the rapid development of cirrhosis and hepatocellular carcinoma. It has been reported that the amount of HCV RNA may be correlated with the progression of hepatitis and may be a prognostic marker for treatment of HCV patients. The direct detection of HCV RNA by reverse transcription-polymerase chain reaction (RT-PCR) is widely used to determine the presence of circulating virions. The most relevant limit of this approach is the lack of quantitative information about the viral titer. In the present study, we developed the method for HCV quantitation using competitive reverse transcription (CRT)-PCR using the deleted HCV standard. The serially diluted standard was added in titrated amounts to the target HCV RNA. The mixture was then reverse transcribed and amplified in the same reaction tube. The methods were evaluated using over 110 HCV-PCR positive samples in Koreans. About 59% of the samples were judged to contain $10^{5}-10^{6}$ copies of HCV RNA in 1 ml of serum.

• Molecules and Cells
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• 제45권3호
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• pp.148-157
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• 2022

Hepatitis C virus (HCV) is a major cause of chronic liver disease and is highly dependent on cellular proteins for viral propagation. Using protein microarray analysis, we identified 90 cellular proteins as HCV nonstructural 5A (NS5A) interacting partners, and selected telomere length regulation protein (TEN1) for further study. TEN1 forms a heterotrimeric complex with CTC and STN1, which is essential for telomere protection and maintenance. Telomere length decreases in patients with active HCV, chronic liver disease, and hepatocellular carcinoma. However, the molecular mechanism of telomere length shortening in HCV-associated disease is largely unknown. In the present study, protein interactions between NS5A and TEN1 were confirmed by immunoprecipitation assays. Silencing of TEN1 reduced both viral RNA and protein expression levels of HCV, while ectopic expression of the siRNA-resistant TEN1 recovered the viral protein level, suggesting that TEN1 was specifically required for HCV propagation. Importantly, we found that TEN1 is re-localized from the nucleus to the cytoplasm in HCV-infected cells. These data suggest that HCV exploits TEN1 to promote viral propagation and that telomere protection is compromised in HCV-infected cells. Overall, our findings provide mechanistic insight into the telomere shortening in HCV-infected cells.

• 대한임상검사과학회지
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• 제39권1호
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• pp.49-55
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• 2007

HCV는 single stranded RNA 바이러스로서 감염 시에는 만성간염 및 간경화 간암으로 진행될 수 있는 가능성이 높다. HCV는 6종의 주된 genotype과 그에 따른 많은 종류의 subtype이 보고되고 있으며, 세계 각 지역별로 그 분포는 매우 다양하다. 여러 가지 HCV genotype 중에서 1b 형에 감염되었을 경우 간경화나 간암으로 진행할 가능성이 높으며 치료효과도 떨어진다는 보고가 있어, 최근 HCV 환자의 치료에 있어서 HCV 바이러스 정량검사와 함께 HCV genotyping 검사의 임상적 활용이 높아지고 있다. 본 연구에서는 PCR-direct sequencing을 이용한 HCV genotyping 검사방법을 이용하여, 한국인 만성 HCV 간염환자에서 HCV genotype의 분포를 조사하였다. 검체로는 232명의 한국인 만성간염환자의 혈청을 사용하였으며, HCV 5'UTR 영역에서 선택한 2쌍의 primer로 nested PCR을 실시하였다. 증폭된 PCR산물 (215 bps)은 2% agrose gel로 전기영동을 하고 sequencing을 실시한 후 GeneBank의 BLAST 프로그램을 사용하여 HCV genotype을 분석하였다. HCV genotyping을 실시한 232명에서 5종류의 genotype, HCV 1b, 2a, 2b, 2c, 3a, 이 발견되었으며, HCV genotype 4, 5, 6 은 검출되지 않았다. 발견된 HCV genotype 중에서 HCV 1b의 검출률이 53.9%로 가장 높았고, 다음은 HCV 2a가 35.8%로 높게 나타나, 위 두 가지 HCV genotype을 합하면 거의 90%였다. 다음으로 HCV genotype 2b가 3.9%, 3a가 3.4% 그리고 2c가 3.0%의 순서로 검출되었다. 본 결과는 한국인 만성 HCV간염 환자의 치료 및 예후관리에 참고가 될 것으로 사료된다. 또한 PCR-direct sequencing을 이용한 HCV genotyping 검사는 간편하고 분명하게 결과를 판독할 수 있어 임상실험실에서 유용하게 사용될 수 있을 것으로 판단된다.

• 대한핵의학회지
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• 제28권2호
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• pp.220-226
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• 1994

RT-PCR법에 의한 HCV-RNA검출을 임상검사에 적용하는 노력의 일환으로 biotin 및 $^{125}I$을 표지시킨 primer를 이용하여 최근 개발되어 있는 상품화된 kit 로 HCV-RNA 검출을 시도하고 그 결과를 평가하여 보았다. 연구대상은 anti-HCV 양성인 118명의 성인환자로, 방법은 환자 혈청내의 HCV-RNA를 guanidium-thiocynate 용액을 이용하여 추출한 뒤 AMPLICIS II $HCV^{(R)}$(CIS, France)kit를 이용하여 cDNA로 역전사 후 1차 증폭을 시행하고, 다시 소량의 1차 증폭산물을 biotin과 $^{125}I$으로 각각 표지된 1쌍의 Primer로 이용하여 2차 증폭을 시행하였다. 증폭산물은 avidin이 코팅된 시험관에 반응시키고 감마선 계수기로 계수하였다. 검사의 재현성을 보기 위하여 anti-HCV 양성인 환자 혈청 중 무작위로 51개의 검체를 선정하여 반복실험하였고, 만성 간질환 환자로부터 얻은 34개의 검체는 본 연구소에서 확립된 다른 RT-PCR 방법으로도 검사를 병행하여 비교하였다. 결과는 다음과 같다. 1) Anti-HCV 양성이면서 조직검사상 만성감염이나 간경화 소견을 보이거나 6개월이상 지속적인 간기능 이상을 나타낸 환자 88명 중 85명 (97%)에서 HCV-RNA 양성이었고, 6개월 이상 간기능이 정상이었던 30명중에서는 73%인 22명에서 HCV-RNA양성 이었다. 2) 두가지 다른 방법으로 RT-PCR을 병행한 34명중, kit를 사용한 경우는 32명(94%)에서 양성소견을 보였고, 기존방법대로 전기 영동 후 ethidium bromide로 염색한 경우는 27명 (79%)에서 양성을 나타내었다. 3) 검사의 재현성을 보기 위하여 anti-HCV 양성인 51개의 검체를 2번 반복 실험하였을때, 82%에서 일치된 결과를 얻을 수 있었다. 이상에서 biotin 및 $^{125}I$ 표지된 primer로 구성된 kit를 이용했을 때 기존방법에 비하여 예민하게 HCV-RNA를 검출할 수 있었다. 그러나 여전히 검사에 많은 노력과 시간이 소요되고 반복 검사시 검사간 변이가 상당히 존재하고 있어 정도관리에 세심한 주의가 필요할 것으로 사료되었다.

• Bulletin of the Korean Chemical Society
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• 제26권2호
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• pp.285-291
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• 2005

The nonstructural protein 5B (NS5B) of hepatitis C virus (HCV) is the viral RNA-dependent RNA polymerase (RdRp), which is the essential catalytic enzyme for the viral replication and is an appealing target for the development of new therapeutic agents against HCV infection. A small amount of serum from a single patient with hepatitis C was used to get the genome of a Korean HCV isolate. Sequence analysis of NS5B 1701 nucleotides showed the genotype of a Korean isolate to be subtype 1b. The soluble recombinant HCV NS5B polymerase lacking the C-terminal 24 amino acids was expressed and purified to homogeneity. With the highly purified NS5B protein, we established in vitro systems for RdRp activity to identify potential polymerase inhibitors. The rhodanine family compounds were found to be potent and specific inhibitors of NS5B from high throughput screening (HTS) assay utilizing the scintillation proximity assay (SPA) system. The binding mode of an inhibitor was analyzed by measuring various kinetic parameters. Lineweaver-Burk plots of the inhibitor suggested it binds not to the active site of NS5B polymerase, but to an allosteric site of the enzyme. The activity of NS5B in in vitro polymerase reactions with homopolymeric RNA requires interaction with multiple substrates that include a template/primer and ribonucleotide triphosphate. Steady-state kinetic parameter, such as Km, was determined for the ribonucleotide triphosphate. One of compounds found interacts directly with the viral polymerase and inhibits RNA synthesis in a manner noncompetitively with respect to UTP. Furthermore, we also investigated the ability of the compound to inhibit NS5B-directed viral RNA replication using the Huh7 cell-based HCV replicon system. The investigation is potentially very useful for the utility of such compounds as anti-hepatitic agents.