• Animal cells and systems
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• v.5 no.3
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• pp.195-198
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• 2001

Hepatitis B virus (HBV) polymerase, which possesses the activities of terminal binding, DNA polymerase, reverse transcriptase and RNaseH, has been shown to accomplish viral DNA replication through a pregenomic intermediate. Because the HBV polymerase has not been purified, the expression of HBV polymerase was examined in an E. coli expression system that is under the regulation of arabinose operon. The expressed individual domain containing terminal binding protein, polymerase, or RNaseH turned out to be insoluble. The activities of those domains were not able to be recovered by denaturation and renaturation using urea or guanidine-HCI. The expressed reverse transcriptase containing the polymerase and RNaseH domains became extensively degraded, whereas the proteolysis was reduced in a Ion- mutant. These results indicate that Lon protease proteolyzes the HBV reverse transcriptase expressed in E. coli.

• Environmental Mutagens and Carcinogens
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• v.15 no.2
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• pp.100-105
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• 1995

The effects of DNA polymerase $\beta$ on the somatic chromosome mutations and mitotic recombinations were investigated using the transgenic Drosophila beating chimetic gene consisting of a promoter region of Drosophila actin 5C gene and rat DNA polymerase $\beta$. For detecting the somatic chromosome mutations and mitotic recombinations, the heterozygous (mwh/+) strains possessing or lacking transgene poi 13 were used. The spontaneous frequency of small mwh spots, due to deletion or nondisjunction etc., in the non-transgenic w strain and the transgenic p[pol $\beta$]-130 strain was 0.351 and 0.606, respectively. The spontaneous frequency (0.063) of large mwh spots, arises mostly from somatic recombination between the centromere and the locus mwh, in the transgenic p[pol $\beta$]-130 strain was about three times higher than that (0.021) of the non-transgenic w strain. The mutant clone frequencies of small and large mwh spots induced by N-methyl-N'-nitro-N-nitrosoguanidine and ethyl methanesulfonate in the transformant p[pol $\beta$]-130 were higher than those in the host strain w. The present results suggest that rat DNA polymerase $\beta$ participate at least in the somatic chromosome mutations and mitotic recombination processes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.991-993
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• 2012

We analyzed RNA polymerase beta subunit gene (rpoB) mutation of rifampin-resistant Mycobacteria through analysis of nucleotide sequence of rpoB DNA (351 bp) containing rifampin resistant region, $rif^r$. For this study, we collected rifampin-resistant Mycobacteria that were identified by conventional culture methods from Masan National Hospital and The Korean Institute of Tuberculosis. We performed sequencing of DNA nucleotides and analyzed rpoB gene of those rifampin-resistant Mycobacteria. From this analysis, we invcestigated diverse mutations of rpoB gene included rifampin-resistant gene, which were not reported, from those rifampin-resistant Mycobacteria.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.264-269
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• 1994

To determine the nucleotide sequence of the ds RNA segment B containing the RNA dependent RNA polymerase (RdRp) gene of the DRT strain of infectious pancreatic necrosis virus (lPNV), the cDNA of the ds RNA segment B of the DRT strain of IPNV was synthesized using the reverse transcriptase (RT)-polymerase chain reaction (PCR) and its cDNA nucleotide sequence was determined. The DRT segment B was 2, 783 bp long and contained only a single long open reading frame (ORF) of 2, 535 bp in length. This ORF nucleotides encoded the VPl protein, the putative RdRp of IPNV. The VPl protein comsisted of 845 amino acids. The molecular weight of the RdRp, as deduced from the nucleotide sequence, is 94, 426. The nucleotide sequence of the ORF of the DRT showed 89.7% homology to the Jasper strain, but 80.8% to the Sp strain. The amino acid sequence of the ORF of the DRT sho.wed 97.6% homology to the Jasper strain, but 88.7% to the Sp strain. The conserved GTP-binding motif was detected in VPl protein.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.1005-1009
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• 2013

Using DNA sequencing method, we analyzed mutations of rpoB (RNA polymerase beta subunit) rifampin-resistant Mycobaterium tuberculosis strains which were identified by conventional test at Masan National Hospital and The Korean Institute of Tuberculosis. Though it has been reported different mutations of rpoB region of rifampin-resistant M. tuberculosis strains in the south of Korea, it is not confirmed whether these mutations of rpoB region actually express rifampin resistance through experiment. We confirmed experimentally these mutations of rpoB region of M. tuberculosis strains induced rifampin-resistance through ampified rpoB by polymerase chain reaction (PCR) and cloning of mutant rpoB into rifampin sensitive-M. tuberculosis strain.

• BMB Reports
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• v.37 no.2
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• pp.167-176
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• 2004

Although efficient antiviral lamivudine is used for HBV-infected patients, a prolonged treatment with nucleoside analogs often results in lamivudine-resistant variants. In this study, we evaluated the fidelity of the lamivudine-resistant variants. The FLAG-tagged wild-type (FPolE) and Met550 variants (FPolE/M550A, M550V, and M550I) of HBV DNA polymerases were expressed in insect cells then purified. Like many other reverse transcriptases, no $3'{\rightarrow}5'$ exonuclease activity was detected in the HBV DNA polymerase. Since there is no proofreading activity, then the use of the site-specific nucleotide misincorporation method is beneficial. From the $f_{ins}$ value analysis, it is evident that M550I and M550V exhibit higher fidelity values than the wild-type HBV DNA polymerase, while M550A exhibits similar fidelity values. It is therefore suggested that lamivudine resistance comes from the stringency to dNTP binding and the discrimination of dCTP and lamivudine in M550V and M550I.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.469-474
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• 1996

A rapid and sensitive method has been developed to detect hepatitis B virus DNA (HBV) by nested polymerase chain reaction (PCR) technique with primers specific for the surface and core regions in capillary thermal cycler within 80 min. The lower limit for detection by present PCR method is $10^{-5}$ pg of recombinant HBV DNA which is equivalent to that determined by one round of PCR amplification and Southern blot hybridization analysis. When boiled HBV positive serum was serially diluted 10-fold, HBV DNA was successfully determined in $1{\mu}l-10^{-3}$ of serum. HBV DNA was detected by present method in 69 clinical samples including HBsAg positives and negatives by enzyme-linked immunosorbent assay (ELISA). When serum samples were amplified by nested PCR using surface and core region primers, HBV DNAs were detected in 37 of 69 samples (53.6%) and 18 of 69 samples (26.1%), respectively. These results can inform the infectious state of HBsAg positive pateints. A simple and rapid nested PCR protocol by using boiled serum as DNA template has been described for the clinical utility to determine HBV DNA in human serum.

• Biomedical Science Letters
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• v.2 no.2
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• pp.223-229
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• 1996

HLA-B27 gene, one of the HLA-class I molecule, is strongly associated with ankylosing spondylitis. It has been most frequently used as a disease-correlated HLA gene by clinicians. In most laboratories, conventional HLA-B27 typing is still performed by cell cytotoxicity tests or fluorescence serology with specific antibodies. In this study, DNA typing method for HLA-B27 was developed by using group specific Polymerase Chain Reaction (PCR). Four HLA-B27 cell lines (HOM-2, JESTHOM, WT24 and BTB) and fifty six B27 Korean individuals defined by serology were used. The results of control cell and B-27 positive individual samples were correlated well with the data which was performed by serological method. All of B27 positive PCR products gave positive signals on Southern blot hybridization with B27 specific probe. This study shows that the HLA-B27 DNA typing is a relatively simple, fast and practical tool for the determination of the HLA-B27 gene in routine clinical laboratory work.

• Journal of Plant Biology
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• v.37 no.1
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• pp.77-83
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• 1994

DNA uptake in dry embryos of rice by DNA imbibition was detected by monitoring the expression of chimeric vectors. The selective markers of expression vectors used were ${\beta}-glucuronidase$ ronidase (GUS) and hygromycin phosphotransferase (HPT) genes under the control of CaMV35 S promoter. Frequency of transient expression of the foreign gene was generally 30-50% varying according to the types of vectors and rice cultivars. Dot blot analysis and DNA sequence analysis of inverse polymerase chain reaction products showed that selected rice in hygromycin B (HmB) medium had HPT gene and CaMV35S promoter DNA sequence in genomic DNA of rice. To investigate what ratio of rice having two marker genes simultaneously as rice embryos imbibed the vector DNA having two HPT and GUS gene, transform ants selected in lImB medium were subjected to PCR for GUS gene. It was shown that about 90 percentage of surviving ones in HmB medium had GUS gene.S gene.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1090-1097
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• 2007

Genomic analysis of Thermococcus sp. NA1 revealed the presence of a 3,927-base-pair (bp) family B-type DNA polymerase gene, TNA1_pol. TNA1_pol, without its intein, was overexpressed in Escherichia coli, purified using metal affinity chromatography, and characterized. TNA1_pol activity was optimal at pH 7.5 and $75^{\circ}C$. TNA1_pol was highly thermostable, with a half-life of 3.5h at $100^{\circ}C$ and 12.5h at $95^{\circ}C$. Polymerase chain reaction parameters of TNA1_pol such as error-rate, processivity, and extension rate were measured in comparison with rTaq, Pfu, and KOD DNA polymerases. TNA1_pol averaged one incorrect bp every 4.45 kilobases (kb), and had a processivity of 150 nucleotides (nt) and an extension rate of 60 bases/s. Thus, TNA1_pol has a much faster elongation rate than Pfu DNA polymerase with 7-fold higher fidelity than that of rTaq.