• YAKHAK HOEJI
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• v.51 no.4
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• pp.239-245
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• 2007

In order to evaluate the genotoxicity of airborne particulate matter extracted with dichloromethane (APE), the rat microsome mediated (S-9) or DNA repair enzyme treated Comet assays were performed using the single cell gel electrophoresis in A549 human lung carcinoma cells. It was found that the cells interacting with APE showed more DNA single-strand breaks relative to untreated cells. The genotoxicity of APE was increased with the treatment of S-9 mixture. Microsome mediated DNA damage was inhibited by CYP1Al inhibitor, quercetin. The APE also showed oxidative DNA damage evaluated by endonuclease III treatment. Oxidative DNA damage of APE was inhibited by antioxidants such as vita- min C and Trolox. We also found that the vegetables or fruits extract may reduce APE-induced genotoxicity by their anti- oxidant activity and CYP1A1 inhibition.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.265-265
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• 1994

본 연구는 간염 바이러스의 X 및 elongated X 유전자를 클로닝하여 E. coli에서 대량 발현시진 후, 그 기능을 여러 측면에서 연구하교 지금까지 알려진 oncogene products, tumor suppressor, 그리고 그 밖의 다른 암 유발인자와의 interaction에 대해 분석함으로써 간암 생성의 분자적 기작을 이해하고 더 나아가 간암의 예방 및 치료제의 개발을 목표로 하였다. 그 일차적 연구로서 이전에 플로닝된 mutant hepatitis Bvirus genome으로부터 X 및 elongated X 유전자를 클로닝하였으며, E. coli에서 대량 발현시키기 위하여 T7 bacteriophage promoter아래에 재 클로닝하였다. 이러한 X 및 ebngated X 유전자를 E. coli에서 대량 발현시킨 후, rabbit anti-X antibody를 이용하여 western blotting을 수행함으로서 이를 확인하였으며 DEAE-cellulose와 heparin-agarose chromategraphy를 이용하여 순수분리하였다. 순수분리된 X 및 etongated X 단백질을 highly differentiated hepatoma cell인 HepG$_2$ cell에 처리하여 transactivation activity를 측정하였다. 그 결과 순수분리된 단백질들이 SV4O promoter를 transactivation 함을 할 수 있었으며, 이로부터 클로닝된 유전자들이 모두 정상적인 기능을 가짐을 확인하였다. 그러고 X 유전자의 작용기작을 규명하기위하여 restriction endonuclease를 이용하여 5 개의 mutant X 유전자를 구성하였으며 현재 이를 HepG2 cell에 transfection 하여 그 기능을 연구하고 있다.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.599-606
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• 1994

Bacillus stearothermomophilus, a strong xylan degrader, was confirmed to express multiple esterase activities in addition to the major xylanolytic enzymes. One of the genes encoding the esterases was isolated from the genomic library of B. stearothermophilus constructed with EcoRl restriction endonuclease and pBR322 plasmid. Three recombinant plasmids showing the tributyrin degrading activity were selected from approximately 7, 000 E. coli HB101 transformants, and were found to have the same insert of a 3.2 kb DNA fragment. Restriction mapping and hybridization studies revealed that the gene(estII) on the hybrid plasmid (pKMG7) had originated from the B. stearothermophilus chromosome, and was distinct from the estl, another esterase gene of B. stearothermophilus isolated in the previous work. The E. coli cells harboring pKMG7 produced an acetylxylan esterase that exibited similar substrate specificity to the esterase encoded by the estI gene.

• Molecules and Cells
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• v.19 no.1
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• pp.54-59
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• 2005

Deoxyribonuclease I (DNase I) is a divalent cation dependent endonuclease and thought to be a significant barrier to effective gene delivery. The only known DNase I-specific inhibitor is monomeric actin which acts by forming a 1:1 complex with DNase I. Its use, however, is restricted because of tendency to polymerize under certain conditions. We screened two random phage peptide libraries of complexity $10^8$ and $10^9$ for DNase I binders as candidates for DNase I inhibitors. A number of DNase I-binding peptide sequences were identified. When these peptides were expressed as fusion proteins with Escherichia coli maltose binding protein, they inhibited the actin-DNase I interaction ($IC_{50}=0.1-0.7{\mu}M$) and DNA degradation by DNase I ($IC_{50}=0.8-8{\mu}M$). Plasmid protection activity in the presence of DNase I was also observed with the fusion proteins. These peptides have the potential to be a useful adjuvant for gene therapy using naked DNA.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1183-1189
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• 2017

Objective: Owing to the public availability of complete genome sequences, including avian species, massive bioinformatics analyses may be conducted for computational gene prediction and the identification of gene regulatory networks through various informatics tools. However, to evaluate the biofunctional activity of a predicted target gene, in vivo and in vitro functional genomic analyses should be a prerequisite. Methods: Due to a lack of quail genomic sequence information, we first identified the partial genomic structure and sequences of the quail SH3 domain containing ring finger 2 (SH3RF2) gene. Subsequently, SH3RF2 was knocked out using clustered regularly interspaced short palindromic repeat/Cas9 technology and single cell-derived SH3RF2 mutant sublines were established to study the biofunctional activity of SH3RF2 in quail myoblast (QM7) cells during muscle differentiation. Results: Through a T7 endonuclease I assay and genotyping analysis, we established an SH3RF2 knockout (KO) QM7#4 subline with 61 and 155 nucleotide deletion mutations in SH3RF2. After the induction of myotube differentiation, the expression profiles were analyzed and compared between regular QM7 and SH3RF2 KO QM7#4 cells by global RNA sequencing and bioinformatics analysis. Conclusion: We did not detect any statistically significant role of SH3RF2 during myotube differentiation in QM7 myoblast cells. However, additional experiments are necessary to examine the biofunctional activity of SH3RF2 in cell proliferation and muscle growth.

• Genomics & Informatics
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• v.13 no.2
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• pp.53-59
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• 2015

In developing countries threat of cholera is a significant health concern whenever water purification and sewage disposal systems are inadequate. Vibrio cholerae is one of the responsible bacteria involved in cholera disease. The complete genome sequence of V. cholerae deciphers the presence of various genes and hypothetical proteins whose function are not yet understood. Hence analyzing and annotating the structure and function of hypothetical proteins is important for understanding the V. cholerae. V. cholerae O139 is the most common and pathogenic bacterial strain among various V. cholerae strains. In this study sequence of six hypothetical proteins of V. cholerae O139 has been annotated from NCBI. Various computational tools and databases have been used to determine domain family, protein-protein interaction, solubility of protein, ligand binding sites etc. The three dimensional structure of two proteins were modeled and their ligand binding sites were identified. We have found domains and families of only one protein. The analysis revealed that these proteins might have antibiotic resistance activity, DNA breaking-rejoining activity, integrase enzyme activity, restriction endonuclease, etc. Structural prediction of these proteins and detection of binding sites from this study would indicate a potential target aiding docking studies for therapeutic designing against cholera.

• Animal cells and systems
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• v.1 no.2
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• pp.363-370
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• 1997

RNase MRP is a ribonucleoprotein complex with a site-specific endonuclease activity. Its original substrate for cleavage is the small mitochondrial RNA near the mitochondrial DNA replication origin, thus it was proposed to generate the primer for mtDNA replication. Recently, it has been shown to have another substrate in the nucleus, such as pre-S.8S ribosomal RNA in nucleolus. The gene for the RNA component of RNase MRP (MRP RNA) was found to be encoded by the nucleus genome, suggesting an interesting intracellular trafficking of MRP RNA to both mitochondria and nucleolus after transcription in nucleus. In this study, genomic DNA encoding MRP RNA was microinjected into the nucleus of Xenopus oocytes, to analyze promoter regions involved in the transcription. It showed that the proximal sequence element and TATA box are important for basal level transcription; octamer motif and Sp1 binding sites are for elevated level transcription. Most of Xenopus MRP RNA was exported out to the cytoplasm following transcription in the nucleus. Utilizing various hybrid constructs, export of MRP RNA was found to be regulated by the promoter and the 5' half of the coding region of the gene. Interestingly, the transcription in nucleus seems to be coupled to the export of MRP RNA to cytoplasm. Intracellular transport of injected MRP RNA can be easily visualized by whole-mount in situ hybridization following microinjection; it also shows possible intra-nuclear sites for transcription and export of MRP RNA.

• Korean Journal of Microbiology
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• v.26 no.2
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• pp.73-81
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• 1988

$\alpha$-Amylase (EC.3.2.1.1) of Neurospora crassa (ATCC9279) was cloned in E. coli HB101 using shotgun method, and the enzymes isolated from both N. crassa and E. coli were compared. Chromosomal DNA isolated from the spores of N. crassa was partially digested with PstI restriction endonuclease and rejoined to pBR322 which had been digested with the same enzyme. The resulting recombinant DNA were introduced into E. coli HB101 which had competancy by treating with $CaCl_{2}$. As the result, about 8000 colonies which showed tetracycline resistance were selected and two of the colonies which had 13.5Kb recombinant plasmid exhibit starch degrading activity on starch-containing plate when treated with D-cycloserine. $\alpha$-Amylases from both N.crassa and E. coli were isolated by using ammonium sulfate precipitation, DEAE-cellulose ion exchange column chromatography and Bio-Gel P150 gel foltration column. As the result, about 81.3 fold and 5.6 fold purifications in specific activities were obtained respectively, and specific activities of the gel filtrates were 6.1u/mg and 85u/mg respectively. The properties of both enzymes were compared and they showed quite the similar patterns in optimal temperature, optimal pH and had same molecular weight about 100,000 daltons on gel filtration method. Optimal temperatures for both enzymes were $70^{\circ}C$ and optimal pH were about 6 and 10.

• BMB Reports
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• v.33 no.2
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• pp.155-161
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• 2000

The saccharomyces cerevisiae Rad27, a structure-specific endonuclease for the okazaski fragment maturation has been known to interact genetically and biochemically with Dna2, an essential enzyme for DNA replication. In an attempt to define the significance of the interaction between the two enzymes, we expressed and purified both Dna2 and Rad27 proteins. In this report, Rad27 could not form a complex with Dna2 in the three different analyses. The analyses included glycerol gradient sedimentation, protein-column chromatography, and coinfection of baculoviruses followed by affinity purification. This is in striking contrast to the previous results that used crude extracts. These results suggest that the interaction between the two proteins is not sufficiently stable or indirect, and thus requires an additional protein(s) in order for Rad27 and Dna2 to form a stable physical complex. This result is consistent with our genetic findings that Schizosaccharomyces pombe Dna2 is capable of interacting with several proteins that include two subunits of polymerase $\delta$, DNA ligase I, as well as Fen-1. In addition, we found that the N-terminal modification of Rad27 abolished its enzymatic activity. Thus, as suspected, we found that on the basis of the structure determination, N-terminal methionine indeed plays an important role in the nucleolytic cleavage reaction.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.663-669
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• 2000

The fur (ferric uptake regulation) expression vector pMON2064 was modified to produce a Fur-fusion expression vector. A kinker site, factor Xa cleavage site, and several restriction endonuclease sites were introduced to facilitate easy cloning and isolating of the fusion protein. The resulting fusion expression vector, pMONSTER, was then used to make fusion expression vector, pMONSTER, was then used to make fusion proteins with $\beta$-galactosidase and the protease of the human immunodeficiency virus type 1 (HIV-1 PR). Strain SW4020 harboring the Fur $\beta$-galactosidase fusion vector produced blue colonies on a 5-bromo-4-chloro-3-indolyl-$\beta$-D-galactoside plate and the resulting 133 kDa fusion protein reacted with an anti-Fur antibody. The strain harboring the Fur-HIV-1 PR fusion vector produced a 29 kDa fusion protein, which also reacted with an anti-Fur antibody. The Fur-HIV-1 PR fusion protein was purified by a single column application that was designed to isolate the Fur protein. The purified Fur-HIV-1 PR fusion protein digested with factor Xa cleaved a recombinant Gag protein to release smaller fragments, including a p24 capsid protein. The Fur-HIV-1 PR fusion protein itself did not exhibit any proteolytic activity.