• Reproductive and Developmental Biology
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• v.30 no.4
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• pp.229-234
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• 2006

We have generated transgenic mice that expressed mouse extracellular superoxide dismutase (EC-SOD) in their skin. In particular, the expression plasmid DNA containing human keratin K14 promoter was used to direct the keratinocyte-specific transcription of the transgene. To compare intron-dependent and intron-independent gene expression, we constructed two vectors. The vector B, which contains the rabbit -globin intron 2, was not effective for mouse EC-SOD overexpression. The EC-SOD transcript was detected in the skin, as determined by Northern blot analysis. Furthermore, EC-SOD protein was detected in the skin tissue, as demonstrated by Western blot analysis. To evaluate the expression levels of EC-SOD in various tissues, we purified EC-SOD from the skin, lungs, brain, kidneys, livers, and spleen of transgenic mice and measured its activities. EC-SOD activities in the transgenic mice skin were approximately 7 fold higher than in wild-type mice. These results suggest that the mouse overexpressing vector not only induces keratinocyte-specific expression of EC-SOD, but also expresses successfully functional EC-SOD. Thus, these transgenic mice appeared to be useful for the expression of the EC-SOD gene and subsequent analysis of various skin changes, such as erythema, inflamation, photoaging, and skin tumors.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.46-51
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• 1995

In order to develope baculovirus expression vector system, we constructed new transfer vector of nuclear polyhedrosis virus of the silkworm, Bombyx mori. The promoter region containing only adenine of translation start codon of polyhedrin gene was cloned by polymerase chain reaction technique. And the 5' and 3' leader regions of polyhedrin gene was sequentially cloned. The polyhedrin coding gene was deleted from the ＋2 to the ＋597 position. As the result, we constructed new transfer vector which has EcoRI, SacI and KpnI sites for the cloning sites of foreign gene. New transfer vector was named as pBmKSKl. Escherichia coli $\beta$-galactosidase gene as foreign gene was inserted into pBmKSKl, under the control of the polyhedrin promoter and expressed in B. mori cells. The result showed that the new transfer vector pBmKSK1 is functional.

• Reproductive and Developmental Biology
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• v.31 no.3
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• pp.161-167
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• 2007

In this study, we constructed and tested retrovirus vectors designed to express the human thrombopoietin gene under the control of the tetracycline-inducible promoters. To increase the hTPO gene expression at him-on state, WPRE sequence was also introduced into retrovirus vector at downstream region of either the hTPO gene or the sequence encoding reverse tetracycline-controlled transactivator (rtTA). Primary culture cells (PFF, porcine fetal fibroblast; CEF, chicken embryonic fibroblast) infected with the recombinant retrovirus were cultured in the medium supplemented with or without doxycycline for 48hr, and induction efficiency was measured by comparing the hTPO gene expression level using RT-PCR, western blot and ELISA. Higher hPTO expression and tighter expression control were observed from the vector in which the WPRE sequence was placed at downstream of the hTPO (in CEF) or rtTA(in PFF) gene. This resulting tetracycline inducible vector system may be helpful in solving serious physiological disturbance problems which have been a major obstacle in successful production of transgenic animals.

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.69-73
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• 2002

For the practical use of nuecin protein, we tried to overexpress nuecin using Bm5 insect cell and Bombyx mori. We inserted nuecin cDNA into pBm10po1-Xa vector derived from B. mori nuclear polyhedrosis virus (BmNPV), and expressed in Bm5 cells and B. mori respectively. SDS-PAGE and Northern blot analysis showed an expressed of the protein when baculovirus expression vector system (BEVS) was used. The amount of intracellular protein is abundant, but the amount of extracellular protein is poor. The results suggest that the biologically active nuecin protein produced by using BEVS is poor because incresed level of misfolded nuecin by the strong promoter, polyhedrin and p 10 of BEVS, decrease the level of free chaperons and foldases by binding with them.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.192-192
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• 1998

The blood - brain barrier (BBB) expresses high concentrations of transferrin receptor, and it was revealed that anti-transferrin receptor mouse monoclonal antibody (OX26) undergoes transcytosis through the BBB. This property allows the OX26 to serve as a brain drug delivery vector. In an attempt to produce broadly useful targeting agents, genetic engineering and expression techniques have been used to produce antibody-avidin (AV) fusion protein (OX26 IgG3C$\_$H/3-AV). In the present study we estimated the BBB permeability and stability of genetically engineered vector.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.509-516
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• 1998

A plasmid vector, pXGPRMATG-lac-Tgx, was developed for overproduction of $\beta$-galactosidase in Escherichia coli using the genetic components of groEx, a heat-shock gene cloned from symbiotic X-bacteria in Amoeba proteus. The vector is composed of intragenic promoters P3 and P4 of groEx, the structural gene of lac operon, transcription tenninator signals of lac and groEx, and ColEl and amp'of pBluescript SKII. The optimized host, E. coli DH5$\alpha$, transfonned with the vector constitutively produced 117,310-171,961 Miller units of $\beta$-galactosidase per mg protein in crude extract. The amount of enzyme in crude extract was 53% of total water-soluble proteins. About 43% of the enzyme could be purified to a specific activity of 322,249 Miller units/mg protein after two-fold purification, using two cycles of precipitation with ammonium sulfate and one step of gel filtration. Thus, the expression system developed in this study presents a low-cost and simple method for purifying overproduced $\beta$-galactosidase in E. coli.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.143-149
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• 2005

We have demonstrated previously on a replication incompetent recombinant adenoviral vector, AdLPCD, in which the expression of cytosine deaminase (CD) gene is driven by the tumor-specific L-plastin promoter. The object of this study was to evaluate the efficacy of AdLPCD together with 5-fluorocytosine (5-FC) in suppression of the growth of established human tumor cells of ovary, Consistent with the knowledge that infection of OVCAR-3 cells with AdLPCD resulted in expression of a functional intracellular CD enzyme capable of converting 5-FC to 5-fluorouracil (5-FU) (Chung and Deisseroth, 2004), statistically significant differences in cytotoxicity were observed when AdLPCD infected cells were also exposed to 5-FC for 6 days (p=0.05), 9 days (p<0.0005) and 12 days (p<0.005), compared to 5-FC exposure alone, These results indicate that the CD gene delivered by adenoviral vector could efficiently sensitize OVCAR-3, otherwise non-toxic 5-FC. On the other hand, SKOV-3 cells, an ovarian carcinoma cell line, were more resistant to the CD/5-FC strategy compared with OVCAR-3 cells under the same condition. The results of present study suggest that the replacement of 5-FU with CD/5-FC in combination chemotherapy would be less toxic and much greater cytotoxicity than the conventional combination chemotherapy in some patients.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.240-245
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• 1991

We have constructed a promoter-probe vector pKU20 using pKT230, a derivative of broad-host-range plsmid RSF1010, as a base. The pKU20 contains structural gene for aminoglycoside phos-photransferase (aph), without promoter, and a multiple cloning site upstream the aph. Using this vector, a 412base pairs (bp) PstI fragment showing strong promoter activity both in Escherichia coli LE392 and Pseudomonas putida KCTC1644 has been cloned from Pseudomonas fluorescens chromosomal DNA on the basis of streptomycin resistance. The nucleotide sequence of the 412 bp fragment has been determined and the putative - 35 and -10 region was observed. Insecticidal protein gene of Bacillus thuringiensis subsp. kurstaki HD-73 inserted on downstream of the promoterlike DNA fragment was efficiently expressed in E. coli and P. putida. The toxin protein was efficiently synthesized in an insoluble form in both strains.

• KSBB Journal
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• v.5 no.1
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• pp.49-58
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• 1990

We constructed hybrid plasmids to allow controlled and extracellular production of human alpha-interferon in Escherichia coli. The hybrid plassmids were constructed by transferring alpha-lFN gene from plasmid Hif-2h which has the alpha-lFN gene at PstI restriction site of pBR322, to plasmids pIN -IIIB3 and pIN-IIIC3 at restriction sites between HindIII and BamHI. Plasmids pIN-IIIB3 and pIN-IIIC3 carry E. coli lipoprotein promoter, lac promoter and operator in tandem. The plasmids also have lacl genes which encode for lac repressors, which allows controlled expression of genes cloned to the plasmids by using of inducer IPTG. Lipoprotein signal sequence is located just ahead of cloning sites of the plasmids, which helps cells to excrete or secrete cloned gene products. Plasmid pUC9 was used as a intermediate vector for transferring of alpha-lFN gene from Hif-2h to pIN vectors in order to solve the problem of different restriction sites between Hif-2h and pIN vectors.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.259-268
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• 2003

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinoma cells and is known to prevent symptomatic rotavirus infections. In this study, we tried to transfer the human lactadherin gene to the Chinese Hamster Ovary (CHO) cells using retrovirus vector system and tested inducible expression of the gene under the tetracycline-controllable promoter. At first, tetracycline-mediated inducibility was tested using E.coli LacZ marker gene. NIH3T3 cells co-infected with RevTet-On and RevTRE-LacZ retrovirus vectors showed that the cells responded to doxycycline (a derivative of tetracycline) in a dose-dependent manner, and prominent induction of the lacZ gene expression was observed from 1 $\mu\textrm{g}$/ml of doxycycline concentration. Based on the results of the pilot experiment, inductional expression of the human lactadherin gene was conducted using RevTet-On and RevTRE-Ltd retrovirus vectors. Analysis with the RT-PCR demonstrated successful inductional expression of the lactadherin gene in the Chinese Hamster Ovary (CHO) cells. Considering that constitutive overexpression of the exogenous genes in the target cells causes serious physiological imbalance, the results obtained in this study will be very useful especially in the studies of gene therapy and transgenic animal production.