• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.69-73
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• 1998

We have cloned and analyzed cDNA coding for nucleocapsid protein N from infectious hematopoietic necrosis virus(IHNV), IHNV-PRT, which was isolated in Korea. The N gene had open reading frame of 1,176 bp that encoded a 391 amino acids with a molecular weight of 42.3 kDa. The deduced amino acid sequence of N protein was 75-90% identical to those of foreign isolates, IHNV, but was 43% and 38% identical to those of other species of fish rhabdovirus, hirame rhabdovirus(HRV) and viral hemorrahagic septicemia virus(VHSV), respectively. However, it revealed high levels of sequence identity between 214-265 amino acid sequences among all species of fish rhabdovirus.

• BMB Reports
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• v.42 no.1
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• pp.59-64
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• 2009

Hepatitis B virus (HBV) infection is highly prevalent worldwide. The major challenge for current antiviral treatment is the elevated drug resistance that occurs via rapid viral mutagenesis. In this study, we developed AAV vectors to simultaneously deliver two or three shRNAs targeting different HBV-related genes. These vectors showed markedly better antiviral effects than ones that delivered a single shRNA in vitro. A dual shRNA expression vector (AAV-157i/1694i), which simultaneously expressed two shRNAs targeted the S and X genes of HBV, reduced HBsAg, HBeAg and HBV DNA levels by $87{\pm}4$, $80.3{\pm}2.6$ and $86.2{\pm}7%$ respectively, eight days post-transduction. In a mouse model of prophylactic treatment, HBsAg and HBeAg were reduced to undetectable levels and the serum HBV DNA level was reduced by at least 100 fold. These results indicate that AAV-157i/1694i generates potent anti-HBV effects and that the strategy of constructing multi-shRNA expression vectors may lead to enhanced anti-HBV efficacy and overcome the evading mechanism of the virus and thus the development of drug resistance.

• Journal of fish pathology
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• v.26 no.1
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• pp.19-30
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• 2013

Megalocytivirus is a major fish pathogen in marine aquaculture of Asian countries including Korea. Despite of many species affected by this pathogen, little is known interaction between megalocytivirus and the fish immune system. One of the cyclooxygenase isoforms, named COX-2, is playing an important role in immune regulation, and distinct from COX-1 isoform of constitutive activity. COX-2 enzyme is induced by various inflammatory signals, including injection of lipopolysaccharide or infection by pathogenic agents. We cloned COX-2 gene in rock bream using degenerated primers designed from reported sequences of other fish species in PCR followed with 5'- and 3'-end RACE-PCR. The full length of cDNA of rbCOX2 (rock bream COX-2) gene are 2655 bp and that translates into 609 amino acids. The rbCOX-2 genomic organization are found to span 10 exons separated by 9 introns. We also studied if the experimental infection of rock bream with megalocytivirus could affect the expression of COX-2 gene. When injected with LPS, expression of the COX-2 gene was reached peak level at 1 day post injection and showed 13.10 fold increased level compared with that of control. While, when injected with megalocytivirus, we were not able to find significantly increased COX-2 gene expression different from that of control. Cloned and analyzed COX-2 gene in rock bream will help to understand defence mechanisms in fish after viral infection and will also support the development of the measures for treatment and prevention of viral infection.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.726-735
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• 2020

Objective: Recent innovations in biology are boosting gene and cell therapy, but monitoring the response to these treatments is difficult. The purpose of this study was to find an MRI-reporter gene that can be used to monitor gene or cell therapy and that can be delivered without a viral vector, as viral vector delivery methods can result in long-term complications. Materials and Methods: CMV promoter-human organic anion transporting polypeptide 1B3 (CMV-hOATP1B3) cDNA or CMV-blank DNA (control) was transfected into HEK293 cells using Lipofectamine. OATP1B3 expression was confirmed by western blotting and confocal microscopy. In vitro cell phantoms were made using transfected HEK293 cells cultured in various concentrations of gadoxetic acid for 24 hours, and images of the phantoms were made with a 9.4T micro-MRI. In vivo xenograft tumors were made by implanting HEK293 cells transfected with CMV-hOATP1B3 (n = 4) or CMV-blank (n = 4) in 8-week-old male nude mice, and MRI was performed before and after intravenous injection of gadoxetic acid (1.2 µL/g). Results: Western blot and confocal microscopy after immunofluorescence staining revealed that only CMV-hOATP1B3-transfected HEK293 cells produced abundant OATP1B3, which localized at the cell membrane. OATP1B3 expression levels remained high through the 25th subculture cycle, but decreased substantially by the 50th subculture cycle. MRI of cell phantoms showed that only the CMV-hOATP1B3-transfected cells produced a significant contrast enhancement effect. In vivo MRI of xenograft tumors revealed that only CMV-hOATP1B3-transfected HEK293 tumors demonstrated a T1 contrast effect, which lasted for at least 5 hours. Conclusion: The human endogenous OATP1B3 gene can be non-virally delivered into cells to induce transient OATP1B3 expression, leading to gadoxetic acid-mediated enhancement on MRI. These results indicate that hOATP1B3 can serve as an MRI-reporter gene while minimizing the risk of long-term complications.

• Journal of Life Science
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• v.28 no.9
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• pp.1007-1015
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• 2018

The E6-associated protein (E6AP) is known to induce the ubiquitination and proteasomal degradation of HCV core protein and thereby directly impair capsid assembly, resulting in a decline in HCV replication. To counteract this anti-viral host defense system, HCV core protein has evolved a strategy to inhibit E6AP expression via DNA methylation. In the present study, we further explored the mechanism by which HCV core protein inhibits E6AP expression. HCV core protein upregulated both the protein levels and enzyme activities of DNA methyltransferase 1 (DNMT1), DNMT3a, and DNMT3b to inhibit E6AP expression via promoter hypermethylation in HepG2 cells but not in Hep3B cells, which do not express p53. Interestingly, p53 overexpression alone in Hep3B cells was sufficient to activate DNMTs in the absence of HCV core protein and thereby inhibit E6AP expression via promoter hypermethylation. In addition, upregulation of p53 was absolutely required for the HCV core protein to inhibit E6AP expression via promoter hypermethylation, as evidenced by both p53 knockdown and ectopic expression experiments. Accordingly, levels of the ubiquitinated forms of HCV core protein were lower in HepG2 cells than in Hep3B cells. Based on these observations, we conclude that HCV core protein evades ubiquitin-dependent proteasomal degradation in a p53-dependent manner.

• Korean Journal of Veterinary Service
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• v.39 no.2
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• pp.107-116
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• 2016

In the study, we developed and evaluated a uracil N-glycosylase (UNG)-supplemented single-tube nested reverse transcription-polymerase chain reaction (UsnRT-PCR) assay that can carried out first-round RT-PCR and second-round nested PCR in a reaction tube without reaction tube opening and can simultaneously detect EU- and NA-PRRSV. The UsnRT-PCR confirmed to have a preventing ability of mis-amplification by contamination of pre-amplified PRRSV DNA from previous UsnRT-PCR. Primer specificities were evaluated with RNAs extracted from 8 viral strains and our results revealed that the primers had a high specificity for both genotypes of PRRSV. The sensitivity of the UsnRT-PCR was 0.1 $TCID_{50}$/0.1 mL for EU- or NA-PRRSV, respectively, which is comparable to that of previously reported real time RT-PCR (RRT-PCR). Clinical evaluation on 110 field samples (60 sera and 50 lung tissues) by the UsnRT-PCR and the RRT-PCR showed that detection rates of the UsnRT-PCR was 70% (77/110), and was relatively higher than that of the RRT-PCR (69.1%, 76/110). The percent positive or negative agreement of the UsnRT-PCR compared to RRT-PCR was 96.1% (73/76) or 90.9% (30/33), showing that the test results of both assays may be different for some clinical samples. Therefore, it is recommend that diagnostic laboratory workers use the two diagnostic assays for the correct diagnosis for the relevant samples in the swine disease diagnostic laboratories. In conclusion, the UsnRT-PCR assay can be applied for the rapid, and reliable diagnosis of PRRSV without concerns about preamplified DNA carryover contamination that can occurred in PCR process in the swine disease diagnostic laboratories.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1583-1590
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• 2006

T4 endonuclease V (T4 endo V) [EC 3. 1. 25. 1], found in bacteriophage T4, is responsible for excision repair of damaged DNA. The enzyme possesses two activities: a cyclobutane pyrimidine dimer DNA glycosylase (CPD glycosylase) and an apyrimidic/apurinic endonuclease (AP lyase). T4 denV (414 bp cDNA) encoding T4 en do V (138 amino acid) was synthesized and expressed using either an expression vector, pTriEx-4, in E. coli or a baculovirus AcNPV vector, pBacPAK8, in insect cells. The recombinant His-Tag/T4 endo V (rHis-Tag/T4 endo V) protein expressed from bacteria was purified using one-step affinity chromatography with a HiTrap Chelating HP column and used to make rabbit anti-His-Tag/T4 endo V polyclonal antibody for detection of recombinant T4 endo V (rT4 endo V) expressed in insect cells. In the meantime, the recombinant baculovirus was obtained by cotransfection of BacPAK6 viral DNA and pBP/T4 endo V in Spodoptera frugiperda (Sf21) insect cells, and used to infect Sf21 cells to overexpress T4 endo V protein. The level of rT4 endo V protein expressed in Sf21 cells was optimized by varying the virus titers and time course of infection. The optimal expression condition was set as follows; infection of the cells at a MOI of 10 and harvest at 96 h post-infection. Under these conditions, we estimated the amount of rT4 endo V produced in the baculovirus expression vector system to be 125 mg/l. The rT4 endo V was purified to homogeneity by a rapid procedure, consisting of ion-exchange, affinity, and reversed phase chromatographies, based on FPLC. The rT4 endo V positively reacted to an antiserum made against rHis-Tag/T4 endo V and showed a residual nicking activity against CPD-containing DNA caused by UV. This is the first report to have T4 endo V expressed in an insect system to exclude the toxic effect of a bacterial expression system, retaining enzymatic activity.

• Molecules and Cells
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• v.44 no.3
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• pp.146-159
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• 2021

DNA methylation, and consequent down-regulation, of tumour suppressor genes occurs in response to epigenetic stimuli during cancer development. Similarly, human oncoviruses, including human papillomavirus (HPV), up-regulate and augment DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities, thereby decreasing tumour suppressor genes (TSGs) expression. Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), an epigenetic regulator of DNA methylation, is overexpressed in HPV-induced cervical cancers. Here, we investigated the role of UHRF1 in cervical cancer by knocking down its expression in HeLa cells using lentiviral-encoded short hairpin (sh)RNA and performing cDNA microarrays. We detected significantly elevated expression of thioredoxin-interacting protein (TXNIP), a known TSG, in UHRF1-knockdown cells, and this gene is hypermethylated in cervical cancer tissue and cell lines, as indicated by whole-genome methylation analysis. Up-regulation of UHRF1 and decreased TXNIP were further detected in cervical cancer by western blot and immunohistochemistry and confirmed by Oncomine database analysis. Using chromatin immunoprecipitation, we identified the inverted CCAAT domain-containing UHRF1-binding site in the TXNIP promoter and demonstrated UHRF1 knockdown decreases UHRF1 promoter binding and enhances TXNIP expression through demethylation of this region. TXNIP promoter CpG methylation was further confirmed in cervical cancer tissue by pyrosequencing and methylation-specific polymerase chain reaction. Critically, down-regulation of UHRF1 by siRNA or UHRF1 antagonist (thymoquinone) induces cell cycle arrest and apoptosis, and ubiquitin-specific protease 7 (USP7), which stabilises and promotes UHRF1 function, is increased by HPV viral protein E6/E7 overexpression. These results indicate HPV might induce carcinogenesis through UHRF1-mediated TXNIP promoter methylation, thus suggesting a possible link between CpG methylation and cervical cancer.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.199-208
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• 2015

Biologics and medical devices manufactured with bovine-derived raw materials have the risk of viral contamination. Therefore, viral validation study is essential to ensure the safety of the products. Bovine adenovirus type-1 (BAdV-1) is one of the common bovine viral pathogens. For quantitative detection of BAdV-1 during the manufacture of biologics and medical devices, a TaqMan probe real-time PCR method was developed. Specific primers and TaqMan probe for amplifying and detecting BAdV-1 DNA were designed. Specificity, limit of detection (LOD), and robustness of the method was validated according to international guideline on the validation of nucleic acid amplification tests for the pathogen detection. The sensitivity of the assay was found to be $7.44{\times}10^1\;TCID_{50}/ml$. The real-time PCR method was reproducible, very specific to BAdV-1, and robust. Moreover, the method was successfully applied to the validation of Chinese Hamster Ovary (CHO)-K1 cells artificially infected with BAdV-1, a commercial CHO master bank, and bovine type 1 collagen. The overall results indicate that this rapid, specific, sensitive, and robust assay can be reliably used for quantitative detection of BAdV-1 contamination during the manufacture of biologics and medical devices using bovine-derived raw materials.

• The Journal of Korean Society of Virology
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• v.29 no.1
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• pp.45-53
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• 1999

We examined the hepatitis G virus infections among 227 Koreans who were healthy or were suspected of hepatitis and determined the phylogenetic relationship based on a part of the NS-5 region of 5 positive samples. Viral RNA was extracted from sera and cDNA was synthesized and subsequently amplified by RT-PCR (reverse transcription-polymerase chain reaction) or RT-nested PCR using random hexamer and NS-5 specific primers (470-20-1-77F, 470-20-1-211R, HGVNESTFO, HGVNESTRE). Five positives were found to belong to samples of patients showing symptoms of viral hepatitis. Primers used for PCR or nested PCR were derived from the NS-5 region. On the other hand, no amplification was detected using primers derived from the 5'-NCR (G-146F, G-401R). We performed TA cloning and sequencing of 5 amplified fragments, and their sequences were compared with those of foreign isolates of HGV. The phylogenetic analysis using MegAlign programme of DNAstar has shown that the Korean isolates are clustered on the phylogenetic tree. In summary, we confirmed the hepatitis G virus infection in 5 cases out of 12 patients showing the symptoms of viral hepatitis. The phylogenetic analysis of sequences of 5 amplified fragments showed that their relations to each other were closer than those to the foreign HGV isolates reported.